Frontiers of Agriculture in China

Published by Springer Verlag
Online ISSN: 1673-744X
Print ISSN: 1673-7334
Publications
The efficient acceptors for maize transgenic engineering are currently insufficient in China. Seed production by male sterility is the best method for advancing the authenticity of maize hybrid. Maize inbred line 18–599 (white) is an antivirus high-quality maize inbred line in China, which has been used for lots of maize hybrid cultivars. The establishment of high efficiency transgenic acceptors is necessary for advancing the transgenic efficiency in maize transformation work. In this study, the efficient transgenic acceptors were optimized and established. 18–599 (white) was studied in state, types of culture mediums, times of callus regeneration and concentration of the screening reagent, Basta. The results showed that N6-4 medium was the best in 8 types of mediums for the immature embryo of 18–599 (white), 1.6 mm length was the feasible length of immature embryos for tissue culture in establishing the transgenic acceptor system, and it was within 5 times for suitable callus subculture. With the optimized transgenic acceptors, barnase gene was translated successfully into 18–599 (white) by a particle gun using bar as a marker gene. Basta was used as the screening reagent, its lethal concentration was 8 mg·L−1 and its working concentration for screening was 6, 8 and 6 mg·L−1 in 3 turns for callus regeneration, respectively. In this work, a transgenic plant with male sterility was obtained through molecule detection and observation in the field. The result has an important significance for the creation of new male sterility inbred lines in maize in the future.
 
In order to investigate its distribution in different goat populations, one SNP (184C→T, corresponding to AY850925) of goat callipyge (CLPG) gene recognized by Fork I was identified after sequencing 23 individuals from 10 breeds. PCR-RFLP was carried out according to the variation site in 584 goats of 14 populations from 11 provinces and autonomous regions in China. An interesting result was found that the Boer goat having the characteristics of double muscle had significantly higher T allele (0.2465) frequency and lower C allele (0.7535) frequency compared to other breeds. It could be inferred that the 184C→T mutation might be related to the double muscle characteristics of the Boer goat. The general linear model analysis showed that parental genotype had significant effect on the body weight of their offspring at different ages. It could be inferred that transition of 184C→T might be a paternal imprinting form, a polar over-dominance, in which only individuals that received the allele from their mother expressed the callipyge phenotype. The double muscle characteristics of the Boer goat might be related to its maternal genotype. More data with detailed information need to be investigated in order to confirm this assumption.
 
Improved soybean cultivars are cultivars released from a scientific breeding program in China in contrast to the historical landraces kept by farmers from their own seed lots. The pedigree data of 1300 soybean cultivars [Glycine max (L.) Merr.] released in China from 1923 to 2005 were collected, checked, and corrected. These cultivars traced back to 670 nuclear and 344 cytoplasmic ancestors; 45% (50%) of the nuclear (cytoplasmic) germplasms were from Eco-region I, 23% (26%) from II, 7% (10%) from III, 4% (5%) from IV, 1% (1%) from V, 1% (1%) from VI, 18% (7%) from foreign countries, and 0% (1%) from geographically unknown sources. Both nuclear and cytoplasmic germplasm from Eco-regions I, II, and III, and foreign countries accounted for most of the ancestry of the released cultivars. In each of the eco-regions, with the exception of region VI, but especially in region I, the local nuclear and cytoplasmic germplasm was dominant in the released cultivars. Exotic germplasm accounted for an increasing portion of the nuclear and cytoplasmic germplasm, especially in Ecoregions I and II. The genetic base of the released cultivars is relatively narrow but has been gradually broadened, especially in Eco-regions I and II; and the average number of ancestors per cultivar released between 1996 and 2005 in various eco-regions was approximately double the period between 1986 and 1995. Seventy-eight ancestors accounted for 12% of the total ancestors but explained that 64% of the nuclear contribution and 70% of the cytoplasmic contribution to the 1300 released cultivars. For broadening the genetic base of future cultivars, the utilization of germplasm from outside regions is emphasized. Keywordssoybean [Glycine max (L.) Merr.]-ancestor-nuclear contribution-cytoplasmic contribution-genetic base broadening
 
Identification of genes related to flowering-time in Arabidopsis is very important and meaningful contribution to the flowering process control. One late flowering mutant plant, which exhibits 60-day delay in flowering, was screened from Arabidopsis library of T-DNA insertion. Southern blotting was used to confirm the single copy of exogenetic T-DNA in the genome of the mutant. The flanking sequence of T-DNA insert was obtained by TAIL-PCR and then analyzed by BLAST to confirm that the insertion site locates at the sixth exon of AT2G19520.1 (FVE gene). FVE is considered as a classical flowering time gene in Arabidopsis. It is a component of the autonomous pathway that encodes AtMSI4, which is a putative retinoblastoma-associated protein. The late-flowering mutant is named as fve-4, which is similar to fve-3 of Columbia and allelic with fve-1 and fve-2 of Landsberg erecta. The fve-4 mutant’s delay of flowering was longer than that of fve-3 mutant, whose T-DNA insertion is located at the first exon of FVE gene, suggesting that the sixth exon of FVE gene may play a more important role in the control of floral transition. Keywordsdelay of flowering– FVE gene– Arabidopsis –gene identification
 
Yali is one of the best pear cultivars cultivated extensively in China and other countries. However, mortality rates of explants during the initial phase of tissue culture were found to be very high during the summer particularly from the shoot tip explants. A thorough investigation on the browning problem of Yali Aikansui and Abbe Fetel pears was done and their control measures are suggested in this paper. Emphasis has been given to the Yali pear. Shoot explants were collected from the field as well as from the plantlets grown in vitro during different months and observed for browning. The explants were excised and cultured in Murashige and Skoog (MS) solid and liquid medium as needed. The cultures were maintained in the dark as well as in a 16/8 hours light/dark photoperiod regime as needed and were kept in a growth room at (25±2)°C temperature. According to the experimental results, Yali was found more severely infected by browning than the other two cultivars. Similarly, it was also found that, the intensity of browning was less during spring and increased with time and reached the maximum during summer. Shoot tips of Yali were found more severely infected by browning than the second node and other nodes. This accelerated the mortality rate up to 81% of shoot explants during the summer months of July and August. Browning was greatly influenced by water-soluble polyphenols, more of which were found in the shoot tip of explants collected from the field (significantly higher at P ⩽ 0.05 and P ⩽ 0.01). Total polyphenol contents were found less in the explants from plantlets grown in vitro, and less browning of medium appeared resulting in a lower mortality rate of explants. Collections of explants during early spring (P ⩽ 0.05 and P ⩽ 0.01) and use of other nodes rather shoot tip because explants (P ⩽ 0.05 and P ⩽ 0.01) were found to be better in preventing the browning problem. Finally, for curative measures to control browning, use of ascorbic acid at the rate of 100 mg·L−1 (P ⩽ 0.05 and P ⩽ 0.01), 0.02%polyvinyl pyrrolidone (PVP) in the culture medium (P ⩽ 0.05), 96 hours dark treatment of other nodes (P ⩽ 0.05), and 12 hours cold treatments of explants at 4°C (P ⩽ 0.05 and P ⩽ 0.01) prior to sterilization of explants, were found to be the best methods to control browning and therefore to increase the survival rate of cultured explants of the Yali pear.
 
Shoot height (SH), root length (RL), number of leaves (NL), leaf area (LA), fresh weight (FW) and dry weight (DW) of rice and sorghum seedlings exposed to mannitol induced osmotic stress for 14 days
Osmotic stress is one of the most important abiotic factors which inhibit growth and development in both the vegetative and reproductive stages of many plant species. The aim of this investigation was to compare the biochemical and physiological responses in C3 rice and C4 sorghum to water deficit. Chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (TC) and total carotenoid (Cx+c) contents in both rice and sorghum seedlings under osmotic stress were adversely affected, related to increasing osmotic pressure in the culture media. In addition, the chlorophyll’s fluorescence parameters and net photosynthetic rate (P n ) decreased, leading to growth reduction. Also, a positive correlation was found between physiological and biochemical data, while proline accumulation showed a negative relationship. The Chlb, P n and fresh weight were maintained better in osmotic-stressed (− 1.205 MPa) C4 sorghum seedlings than those in C3 rice seedlings. The growth and physiological responses of C3 rice and C4 sorghum decreased depending on the plant species, the osmotic pressure in the media and their interactions. Pigment content and P n ability in C4 sorghum grown under mannitol-induced osmotic stress increased to a greater degree than in C3 rice, resulting in maintenance of growth.
 
Mitogen-activated protein kinase (MAPK) cascade plays a central role in transfer information from diverse receptors/sensors to a wide range of cellular responses in plants. MAP kinases are organized into a complex network for efficient transmission of specific stimuli, including the abiotic stress signaling. In recent years, the mutants of loss-offunction and gain-of-function, and other additional tools are used to investigate the plant MAPK cascades. This review has summarized the recent progress on the MAPK cascade involved in mediation of the transduction of several pronounced abiotic stress signalings, such as salt, drought, low and high temperature, wound, hormone, and deficient nutrients. Currently, although part of the components of the MAPK cascade responding to the abiotic stresses have been identified, the integral molecular mechanisms of the abiotic stresses signaling transduction mediated viaMAPK cascade are largely unknown and need to be elucidated further in the future. KeywordsMAP kinase–abiotic stress–signaling–signal transduction–molecular mechanism
 
Mean population of thrips, mites per leaf, and field cricket per plant recorded on mung bean crop affected by date of observation, varieties, and their interactions
Effect of temperature and relative humidity on population of Thrips tabaci on mung bean.
Relationship between population of insect pests and temperature and relative humidity in mung bean crop
Effects of temperature and relative humidity on the population of Tetranychus urticae on mung bean.
Effect of temperature and relative humidity on population dynamics of insect pests of mung bean was studied during mung bean growing season of 2005. Insect pests included thrips (Thrips tabaci Lind.) and field cricket (Gryllus assimilis) and one arachnid pest mite (Tetranychus urticae Koch). Results revealed that the maximum population of thrips and mites was observed on August 23, 2005 with 1.537±0.031 per leaf and July 6, 2005 with 3.271±0.09 per leaf, respectively. The population of field cricket differed significantly during crop season and reached its peak during the initial stage of crop growth on June 14, 2005, i.e., 0.873±0.014 per plant at the temperature and relative humidity of 32°C and 54%, respectively, while the minimum population was noted on August, i.e., 0.710±0.010 per plant. Present studies conclusively document the correlation of weather factors and insect pest population. Temperature had a negative and significant correlation with thrips (r = −0.860) and a positive and significant correlation with mites (r = 0.606) and field cricket (r = 0.439). However, the relative humidity displayed a positive and significant correlation with thrips (r = 0.569), a negative non-significant correlation with mites (r = −0.313), and a significant negative correlation with field cricket (r = −0.770). Keywordsabiotic factor–insect fauna– Thrips tabaci Lind– Gryllus assimilis – Tetranychus urticae Koch
 
The aim of this study is to investigate the significance of Th1/Th2 cytokine balance in the uterus in the early embryo loss (or resorption), and to elucidate immunological modulation at the maternal-fetal interface with Chinese herbal medicine Radix scutellariae (Huang Qin) and its constituents (Baicalin and Baicalein). Mifepristone (RU486) was given via subcutaneous injection in the scapular area to induce abortion in mice at day 7 of gestation. The levels of uterine Th1 cytokines (IFN-γ, IL-2) and Th2 cytokines (IL-4, IL-10) were analyzed by enzyme-linked immunosorbent assay (ELISA), respectively. The mean values of Th1 cytokines in the uterus of RU486-treated abortion mice were significantly higher (P < 0.05) than that of the control mice, but no significant difference was observed regarding to the contents of Th2 cytokines of different groups (P > 0.05). However, when the Radix scutellariae and its constituents were used to prevent RU486-induced abortion, the levels of IFN-γ and IL-2 decreased while that of IL-4 and IL-10 increased. The embryo loss induced by RU486 was closely related to the Th1/Th2 immune balance at the maternal-fetal interface. Radix scutellariae and its constituents have an anti-abortive effect through restoring the Th1/Th2 balance at the maternal-fetal interface.
 
The objectives of this study were to investigate ethylene and 1-aminocylopropane-1-carboxylic acid (ACC) in rice grains and root bleeding sap during the grain filling period and their relationship to the grain filling rate. Two high lodging-resistant rice (Oryza sativa L.) cultivars were grown in pots or tanks. Three treatments, including well watered (WW), moderate soil-drying (MD) and severe soil-drying (SD), were conducted from 9 days of post-anthesis until maturity. The effects of chemical regulators on the concentrations of ethylene and ACC in the grains were also studied. The results show that MD significantly increased the grainfilling rate and grain weight, whereas SD significantly reduced the grain-filling rate and grain weight. Concentrations of ethylene and ACC in the grains were very high at the early grain filling stage and then sharply decreased during the linear period of grain growth. MD reduced the ACC concentrations and ethylene evolution rate, whereas SD remarkably increased the ACC concentrations and ethylene evolution rate. Both the ethylene evolution rate in rice grains and the ACC concentrations in the root-bleeding sap were significantly and positively correlated with the ACC concentrations in rice grains. The ethylene evolution rate was significantly and negatively correlated with the grain-filling rate. The application of amino-ethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis, at 9–13 days of postanthesis significantly reduced the ACC concentrations and ethylene evolution rate of grains, but significantly enhanced the activities of sucrose synthase, ADP glucose pyrophosphorylase and soluble starch synthase. The results were reversed when ethephon, an ethylenereleasing agent, was applied. The results suggest that moderate soil drying during the grain-filling period in rice could inhibit the production of ethylene and ACC and therefore accelerate grain filling and increase grain weight.
 
Cadmium (Cd) is a toxic environmental pollutant with a long biological half-life and can produce both hepatic and renal injuries in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on the growth and Cd deposition in the tissues of large yellow croaker, Pseudosciaena crocea R. Three practical diets were formulated to contain a 0, 50 and 100 g · kg−1 SVM diet, correspondingly containing a 0.21, 7.26 and 12.08 mg Cd · kg−1 diet. Each diet was randomly assigned to triplicate groups of 100 juveniles of large yellow croaker (mean initial weight, 9.75 ± 0.35 g) in floating sea cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (05:00 and 17:00) to satiation for 8 weeks. The results showed that there were no significant differences in fish survival among the three dietary treatments, but significant higher specific growth rates (SGR) were observed in the fish fed diets with 50 or 100 g · kg−1 SVM diet compared to the control group (P P −1 SVM had significantly higher Cd accumulations in the kidney (2.65, 4.44 mg · kg−1), liver (0.58, 0.93 mg · kg−1) and gill (0.35, 0.53 mg · kg−1) compared with the control group (0.42, 0.26 and 0.12 mg · kg−1, respectively). The Cd level in fish muscle, however, was undetectable in all treatments. Therefore, based on these results, accumulation of Cd in edible tissue (muscle) of farmed large yellow croaker is not a food safety issue. However, long-term feeding of diets with SVM may result in accumulation of Cd in the kidney, liver and gills of fish.
 
A greenhouse experiment was conducted to study the accumulation of selenium by some vegetable crops commonly grown in the Indian Punjab. Eleven vegetable crops were raised in an alkaline clay loam soil treated with different levels of selenate-Se, i.e., 0, 1.25, 2.5 and 5.0 mg·kg−1 soil. Dry matter yield of both edible and inedible portions of different vegetable crops decreased with increasing Se level in soil except potato (Solanum tuberosum), radish (Raphanus sativus) and cauliflower (Brassica oleracea var. botrytis) which recorded 10%–21% increase in inedible dry matter at 1.25 mg·kg−1 Se soil. Application of 5 mg·kg−1 selenate-Se soil resulted in complete mortality in the case of radish, turnip (Brassica rapa) and brinjal (Solanum melongena). Some vegetable crops including tomato (Lycopersicum esculentum), cauliflower and pea (Pisum sativum), though, survived the toxic effect at the highest concentration of Se yet did not bear any fruit. Potato and spinach (Spinacea oleracea) proved to be highly tolerant crops. Selenium concentration in the edible as well as inedible portions of all the vegetables increased with an increase in the level of applied Se. Selenium accumulation in the edible portion of vegetable crops in the no-Se control ranged from 2.2 to 4.9 mg·kg−1 Se dry weight. At 1.25 mg·kg−1 Se soil, the edible portion of radish accumulated the greatest concentration of Se (38 mg·kg−1 Se dry weight) with that of onion (Allium cepa) bulb the lowest (9 mg·kg−1 Se dry weight). Inedible portions of vegetables accumulated Se 2–5 times more than that absorbed by edible portions. Total Se uptake by edible portions of different vegetables was the greatest at 1.25 mg·kg−1 Se soil, ranging from 7 to 485 μg·pot−1. The results suggest that vegetable crops vary in their sensitivity to the presence of selenate-Se in soil. Vegetative portions were several times richer in Se than other parts of vegetable crops.
 
The yield response of Chinese cabbage to phosphate fertilizer and manure was studied. The effect of over-application of phosphate fertilizer and manure on plant total phosphorus content and phosphorus accumulation in soil was also investigated. The experiment was arranged in a plastic barrel in the field for two years. Application of phosphate fertilizer at the rates of 150–600 mg·kg−1 gave a yield increase of 14.9%–21.5% of Chinese cabbage. Application of manure at the rates of 33.3–-133.2 g·kg−1 gave a yield increase of 18.2%–25.9%of the crop. There was no significant difference of yield response at the rates of 150, 300 and 600 mg·kg−1 phosphate fertilizer, and no significant yield response to the application of phosphate fertilizer after applying manure. The total P content in Chinese cabbage was increased gradually with the rate increase of phosphate fertilizer and manure. Phosphorus was absorbed luxuriously by the plant with over-application phosphate fertilizer and manure. The content of total-P, Olsen-P, water-soluble P, biological available P in the soil was increased with the rate of phosphate fertilizer and manure. Organic phosphorus in the soil was increased by the application of manure. Olsen-P had high correlations with water-soluble-P and biological available-P, but there was a poor relationship between Olsen-P and organic-P.
 
The changes in the accumulation of lipoproteins, the relationship between lipoproteins and the dough mixing characteristics of Chinese winter wheat (Triticum aestivum L.) were investigated for six cultivars that differ in quality characteristics and was classified into three groups according to their gluten index. All cultivars were grown under the same experimental field conditions, with three replicates. The lipoproteins were found to accumulate during the early stages of grain development. The rate of lipoproteins’ accumulation appeared to follow a similar pattern of marked increase during the time from 5 DAA (days after anthesis) to 15 DAA, with a peak at 15 DAA, then quickly decreased for the same group of cultivars. Different patterns appeared from 20 DAA until maturity, but those cultivars with medium quality gluten showed a significant decrease during this period. Significant differences were found in lipoproteins for the six cultivars during grain development on the same days after anthesis. Correlation analysis indicated that lipoproteins from 25 DAA to 30 DAA were positively correlated with dough mixing parameters. However, the correlation coefficients were not statistically significant.
 
To reduce nitrate leaching, the effects of three N-catch crops of sweet corn (Zea mays L.), amaranth (Amaranthus spp.), and sweet sorghum (Sorghum Linn.) on nitrate-N accumulation in the soil profile were examined using an incubation experiment. Results showed that the biomass and N absorbed by sweet corn were the largest compared with the other two N-catch crop treatments. Root length density for sweet corn, amaranth, and sweet sorghum in the 0–150 cm soil layer was 0.66, 0.34 and 0.46 cm/cm3, respectively, and root dry weight was 0.065, 0.021 and 0.038 mg/cm3, respectively. In the 0–200 cm soil layer, nitrate-N accumulation for fallow, mature sweet sorghum, amaranth, and sweet corn was 1124.7, 899.4, 867.4 and 794.2 kg/hm2, respectively, where the treatment of sweet corn had the smallest N-accumulation. The nitrate-N leachability of fallow, sweet corn, amaranth, and sweet sorghum treatment was 3.6, 1.9, 2.4 and 2.6 kg/hm2, respectively, indicating that cropping of sweet corn, amaranth, and sweet sorghum could reduce the leachability by 47%, 35% and 28% in comparison with fallow treatment. Therefore, the cultivation of N-catch crops can reduce nitrate leaching in seasonal soil, and the sweet corn might be the most suitable catch crop. KeywordsN-catch crops–soil NO3-N–leaching
 
The ability of salicylic acid (SA) to induce disease resistance was studied with Whangkeumbae pears affected by Alternaria kikuchiana Tanaka. SA (0.02, 0.2 and 2 mmol·L−1 active ingredient) protected Whangkeumbae pear leaves from artificial infection when applied before inoculation. When the concentration of SA reached 0.2 mmol·L−1, the disease-infected index was the lowest, and the rate of induced resistance reached 59.0%. The protection of Whangkeumbae pear leaves was associated with the activation of three defense-related enzymes, SOD, POD and PAL. Accumulation of three enzymes was induced locally in treated leaves and systemically. These results suggested that SA could induce systemic resistance in Whangkeumbae pear leaves by increasing defense-related compounds. KeywordsWhangkeumbae pear- Alternaria kikuchiana Tanaka-salicylic acid-induced resistance
 
A 2431-bp full-length cinnamate 4-hydroxylase gene, BoC4H, was cloned from Brassica oleracea L. var. acephala DC.. It contains 2 introns. Its mRNA is 1715 bp, encoding a deduced 481-amino-acid polypeptide with wide homologies to C4Hs from other plants. It possesses cytochrome P450 conserved domains and motifs such as the haem-iron binding motif, the E-R-R triad, the T-containing binding pocket motif and the hinge motif necessary for optimal orientation of the enzyme. It also has most of the canonical C4H/CYP73A5-featured substrate-recognition sites (SRSs) and active site residues. However, owing to a single-base deletion at C2242 and subsequent frame shift within the 3′ coding region as compared with C4H genes from Arabidopsis thaliana and other plants, BoC4H shows a 36-aa deletion/variation at its C-terminus and the SRS6 motif together with active site residues therein are absent. Thus BoC4H may be of no function or low activity. BoC4H is a membrane protein and is probably associated with the endoplasmic reticulum. Its secondary structure is dominated by alpha helices and random coils. The Swiss-Model could not predict its tertiary structure. B. oleracea contains a C4H gene family with at least 5 members.
 
Antigens of Eimeria acervulina merozoites were prepared and purified. BALB/C mice were inoculated with the merozoite soluble antigens of E. acervulina. The total RNA was extracted from the spleen cells of the immunized BALB/C mice. The first chains of cDNA were synthesized by reverse transcription with Oligo (dT)15 Primer, using extracted RNA as a template. The variable regions of heavy chain (VH) and light chain (VL) genes were amplified by PCR with gene-specific primers. The results showed that the genes of amplified VH and VL were about 420 bp and 390 bp, respectively. PCR products were purified by agarose gel DNA purification kit, and then the VH and VL gene libraries were constructed, respectively. The purified products were cloned into PGM-T vectors. The cloned plasmids were transformed into Escherichia coli TOP10. The colonies were selected on ampicillin-containing agar plates and the plasmids were isolated from several independent clones. The selected colonies were sequenced using Sanger’s dideoxy sequencing method. Nucleotide sequences of the VH and VL genes were compared with the published VH and VL sequences from the BALB/C mice. The sequences were confirmed with mouse antibodies. As expected, the sequence differences between VH/VL and the corresponding germline genes were identified and predominantly localized in complementary determining regions. The sequence analysis results of partial clones indicated that the constructed gene libraries of VL/VH had a good diversity.
 
Concentration of 2-acetyl-1-pyrroline (2-AP) in (a) Guixiangzhan and (b) Peizaruanxiang fragrant rice cultivars as affected by planting density after a storage period of 6 months at –4 and 30°C during the early season of 2008 Note: All samples were stored in paddy form. Data points charted are the mean values of three replicate experiments with the corresponding standard deviations as error bars. Bars sharing a common lower case letter above are different at the P < 0.05 level of significance by Duncan's multiple range test. Table 2 Main effects of planting density on Guixiangzhan and Peizaruanxiang fragrant rice yield, 1000-grain weight, head rice rate, grain vitreosity, amylose content, and protein content during the early season of 2008 rice density /(hill$m –2 )  
Volatile components identified in the headspace of Guixiangzhan and Peizaruanxiang rice and their relative concentrations
Change in 2-acetyl-1-pyrroline (2-AP) concentration in (a) Guixiangzhan and (b) Peizaruanxiang fragrant rice cultivars harvested at different dates after heading (DAH) during the late season of 2008 and subjected for 3 months to different storage temperatures (8 and 20°C) Note: All samples were stored in paddy form. Each vertical bar is the mean of triplicate data with bars representing the standard deviation. Vertical bars with different letters are significantly different (P < 0.05) according to Duncan's multiple range test.  
Main effects of planting density on Guixiangzhan and Peizaruanxiang fragrant rice yield, 1000-grain weight, head rice rate, grain vitreosity, amylose content, and protein content during the early season of 2008
The fragrance potential of two fragrant rice (Oryza sativa L.) cultivars grown in South China was investigated in this study using headspace SPME and static headspace in conjunction with GC-MS. About a five-fold difference of 2-acetyl-1-pyrroline (2-AP) levels were observed among the two fragrant rice cultivars, with Guixiangzhan having the highest content (3.86 μg·g−1) comparable to that obtained with Thai KDML 105 rice. Other compounds instead of 2-AP were assumed to contribute to the characteristic aroma of Peizaruanxiang. The two cultivars were subjected to two preharvest treatments (planting density and harvest date) and different storage conditions (3 to 6 months at −4, 8, 20, and 30°C). Results were discussed in terms of grain yield, milling quality, grain appearance, and amylose and protein contents of rice samples associated with differing treatments. Highest 2-AP concentrations were obtained for Guixiangzhan and Peizaruanxiang with lower planting densities, the earliest harvesting time of 10 days after heading, the shortest storage time of 3 months, and the lowest storage temperature of −4°C. These findings indicate that manipulating pre- and postharvest treatments can greatly improve the specific attributes of the domestically produced cultivars. With that in mind, China could effectively increase its share of the domestic market of fragrant rice and even tap into the international market.
 
Nine multiparous cows averaging 93±13 days in milk production (DIM) were used in a triple 3×3 Latin square design to determine the effects of feeding them whole roasted flaxseed, cracked roasted soybean and fresh alfalfa in the diet on milk production, milk fatty acid profiles and the digestibility of nutrients. Each experimental period lasted 30 d and a sample collection was performed during the last 7 d. The cows were fed on the control basal diet (CON) or diets containing whole roasted flaxseed (FLA) or cracked roasted soybean (SOY). All diets were fed as a total mixed ration (TMR) and had similar concentrations of crude protein (CP), Net Energy Lactation (NEL), acid detergent fibre (ADF) and neutral detergent fibre (NDF). The dry matter intake (DMI) was not significantly different (P>0.05), but tended to increase in FLA and SOY diets compared with the control (P>0.05). Cows in all treatments had a similar milk yield, although 4% fat corrected milk (FCM) yield was higher on the FLA and SOY diets than on the CON diet. Milk fat percentage (3.45%) increased in the FLA diet compared with the control (3.31%) and SOY diets (3.39%). Milk protein percentages were similar among the diets (P>0.05). There were similar digestibilities of DM, CP and ADF among the treatments and lower digestibilities of NDF and ether extract in the SOY diet compared with the CON diet. Feeding various oilseeds significantly increased the concentrations of C18:1, C18:3 and conjugated linoleic acid (CLA). The FLA diet decreased the ratio of omega-6 to omega-3 fatty-acids in the milk, which would improve the nutritive value of the milk.
 
A male sterile germplasm of Chinese jujube (Ziziphus jujuba Mill.), named ‘male sterile No.1’ (JMS1), was firstly identified from a natural population through studies of pollen amount and vitality and its anatomy. Its microspores got massed and then disaggregated after the tetrad stage during pollen development. Then its anthers became empty, or only pollen vestiges remained in the yellow buds. The pollen became abortive after the tetrad stage. Hypertrophy and hyperplasia of tapetum at the tetrad stage were related to pollen abortion. In view of its moderate embryo fertility, big fruit-size and early maturing, ‘JMS1’ could be used as a worthwhile female parent in the cross breeding of Chinese jujube.
 
Due to the huge amount in the soil, phytate is an important potential source for providing the plants with available phosphorus (Pi) by the involved catalytic reaction of phytase. In this study, a construct fusing the open reading frame (ORF) of Sphy1 into corresponding positions in the fragment of binary expression vector pBI121 was created and used to transform tobacco. Molecular identification by PCR and RT-PCR indicated the target gene Sphy1 in the transgenic tobacco plants was transcribed under the regulation of an upstream promoter. Compared with the control plants, the phytase activities in all the transgenic plants were increased, with the increased range consistent with the expression levels in the transgenic plants. Under the growth conditions with phytate as the sole phosphorus source, the transgenic line 1 plants displayed a high expression level of Sphy1 and shows notable improved growth performance, such as higher fresh weight and dry weight, as well as higher total P content and more accumulative P amount per plant than CK. This clearly indicated that overexpression of Sphy1 could improve the phosphorus acquisition by the extruded Sphy1 phytase in the rhizosphere, where this enzyme could catalyze the degradation of the phytate and release the available Pi for plants. The Sphy1 gene seemed to have a potential value in the creation of new crop cultivars with high phosphorus use efficiency.
 
Based on the DNA sequence of ACS9, two produced fragments were subcloned into binary vector pCAMBIA1300 in antisense and sense orientations, and the generated RNA interference (RNAi) vector was then transformed into Arabidopsis thaliana. The stress resistance function of ACS9 gene in Arabidopsis thaliana was researched by determination of stress resistance physiologic indexes, NaCl and PEG6000 resistance. The results showed that the inhibition of ACS9 expression enhanced the sensitivity to high concentration NaCl (150 mmol/L) and PEG6000 (7%) in Arabidopsis thaliana seeding stage. The proline contents and water loss rates in transgenic plants were 0.68 and 1.4 times higher than those in the wild-type leaves, respectively, indicating that the inhibition of ACS9 expression due to salt and drought resistant was reduced and suggested that ACS9 gene played important roles in plant salt and drought tolerance. Keywords ACS9 gene–RNAi vector–functional analysis–stress resistance
 
The cis-acting elements of JCesAP, YCesAP, and MDCesAP were analyzed by the PLACE database, the results showed that three sequences all had a core element and upstream promoter element containing TATA-box and CAAT-box. The sequences related xylem-specific and wound-defense functions were found in YCesAP and MDCesAP; and the “core xylem gene set” in JCesAP, indicating that three sequences were xylem-specific and provided with wound-defense functions. Meanwhile, some other elements were also detected, including some tissue-specific elements and some regulative ones that were induced by light, temperature, and water. For investigating their functions, three sequences of JCesAP, YCesAP, and MDCesAP were respectively combined with the report gene GFP, and those reconstructed GFP genes were respectively transferred into the genome of Populus tomentose by Agrobacterium-mediated transformation method. The detected results of GFP expressions in hygromycin B resistant calli of P. tomentosa showed that three sequences all possessed the promoter functions with tissue-specific characteristics. Keywords Populus -promoter-cis-elements analysis-function detection
 
The herbicidal mechanism of the components extracted from Pythium aphanidermatum was examined in this study. Component I was isolated using the HPD500 macroporous adsorption resin and HPLC. Its impact on seed germination and plant growth of weeds was determined and the contents of MDA, superoxide anion radical, and the activities of hills and roots were examined. The root length of weed plants was inhibited under illumination while the stem height was inhibited evidently under darkness. The relative electric conductivity of Digitaria sanguinalis and Amaranthus retroflexus under illumination was 94.55 μS·cm−1 and 58.75 μS·cm−1, respectively, whereas that under darkness was 85.25 μS·cm−1 and 36.25 μS·cm−1, respectively. The MDA contents of Digitaria sanguinalis and Chlorella pyrenoidosa were 0.08385 μmol·L−1 and 0.1742 μmol·L−1 under illumination, respectively, while those were 0.0129 μmol·L−1 and 0.01935 μmol·L−1 under darkness, respectively. Simultaneously, superoxide anion radical content was higher under illumination than under darkness. These results showed the photosynthesis was affected by component I extracted from Pythium aphanidermatum.
 
Is it possible that Giant Panda (Ailuropoda melanoleuca) post-thawed sperm fertilization is improved with pentoxifylline (PF), platelet activated factor (PAF) and prostaglandin F 2-alpha (PGF2α)? In our study Giant Panda post-thawed sperm was incubated in Ham’s F-10 medium with different concentration of PF, PAF and PGF2α under 37°C. The effects of PF, PAF and PGF2α on Giant Panda post-thawed sperm fertility were evaluated through sperm motility, survival time, sperm membrane integrity, acrosome state and heterospecific egg penetration. The results were that PF, PAF and PGF2α all can affect Giant Panda post-thawed sperm in vitro fertilizing capability. In the experiment: 1 mg·mL−1 PF was most suitable for improving Giant Panda post-thawed sperm in vitro fertilizing capability. In the 1 mg·mL−1 PF group, sperm survival time was (15.33±4.73) h, the heterospecific egg penetration was 51.44% after incubating for 4 hours, the heterospecific egg penetration was 7.49% after incubating for 6 hours. The results of the 1 mg·mL−1 PF group were significantly higher than those of the control group (P<0.01). The results were also higher than those of the other treatment groups; Treated Giant Panda post-thawed sperm with 50 ng·mL−1 PAF had a better effect than 100 ng·mL−1 PAF, but the sperm fertilizing capability was damaged when incubation time exceeded 2 hours; 50 ng·mL−1 PGF2α had no significant effect on Giant Panda postthawed sperm, but when the PGF2α treated concentration was increased, sperm in vitro fertilizing capability decreased because of the damaged motility and declined acrosomal reaction rate. The conclusions suggest that it is possible to improve post-thawed Giant Panda sperm fertility with 1 mg·mL−1 PF.
 
The present experiment was conducted to examine the effect of microenvironments and exogenous substance application on 5′-nucleotidase activity in apple peel tissue. By enclosing apple fruits in bags, treating them with exogenous active oxygen species and regulative agents or placing them under controlled conditions at different fruit temperatures or relative humidity, the 5′-nucleotidase activities were compared with the corresponding controls. The results indicated that, a considerable effect of the microenvironments was found on 5′-nucleotidase activities in fruit peel tissue. The highest enzymatic activity appeared in fruits on the southwest exposure of canopy, regardless of bagged or non-bagged fruits, significantly higher than those from any other exposures. Fruits with bags had a significantly higher 5′-nucleotidase activity than the exposed ones. A variation in enzymatic activities was observed in fruits enclosed with different types of bags, which were supposed to alter the microenvironments around them. Within a certain range, gradual or fluctuating rise of fruit temperatures could favor the increase of 5′-nucleotidase activities as a result of heat adaptation, whereas the activity would be inhibited if the temperature-rising period was too short or temperature differential was too large. No matter what temperatures fruits were subjected to, high relative humidity was favorable for stimulating the 5′-nucleotidase activities, which might partly explain why fruit sunburn would not happen in humid climates. Treatments with four kinds of exogenous active oxygen species could reduce the 5′-nucleotidase activities significantly but spraying with CaCl2 was able to enhance 5′-nucleotidase activities by 55.39%, reaching a 5% significant level.
 
This research was to investigate physiological activities and the expression of insecticidal protein in cotton leaves of Kemian 1, a widely grown cotton cultivar in the lower reaches of the Yangtze River, treated under high (40°C and 35°C) and low (25°C and 20°C) temperatures for 48 h. The main results indicated that the contents of free amino acid and malondialdehyde (MDA) increased during the heat and cold stress with the biggest increments in the first 12 h; and the content of soluble protein, activities of superoxide dismutase (SOD), and glutamic-pyruvic transaminase (GPT) decreased during the stress with the biggest decrements also in the first 12 h; the activity of nitrate reductase (NR) decreased in the first 24 h, and during the remaining 24 h its activity followed a gradual uptrend. The content of insecticidal protein in cotton leaves followed a downtrend during the stress, and the biggest decrements occurred in the first 12 h, suggesting that the expression of insecticidal protein was immediately inhibited during the process of stress. The results also indicated that physiological activities and the expression of insecticidal protein in cotton leaves were closely related. Compared with other stress temperatures, 40°C produced more immediate effects on the physiological activities and insecticidal protein content. In contrast to the peak flowering period, the physiological activities and insecticidal protein expression at the peak boll-setting period were more susceptible to heat and cold stress.
 
To investigate the effects of Shenpang acupoint-stimulation in reproductive endocrinology, the changes in estrogen receptor immunoreactive (ER-IR) neurons after Shenpang acupoint-stimulation were studied by using immunohistochemistry. ER-IR positive reactions were detected in most nuclei of the thalamus. In the acupuncture-treated group, a great number of ER-IR positive neurons with clear dendrites existed in the nucleus, paraventricular nucleus, ventrolateral nucleus, ventromedial nucleus, ventroprincipal nucleus, centromedian nucleus, reticular nucleus, and periventricular nucleus of thalamus, and they were mainly located in the cytoplasm, nucleus and neutrite, and some also existed in the cytoplasmic membrane. In contrast, a few neurons existed in the above-mentioned nuclei in the control group, but they were slightly stained. It is concluded that Shenpang acupoint-stimulation can promote the expression of estrogen receptors in the above nuclei.
 
It has previously been shown that Human Chorionic Gonadotropin (hCG) can stimulate steroidogenesis in Leydig cells. In the present study, the mechanisms of hCG-stimulated steroidogenesis in Leydig cells of immaturated pigs were investigated. It was found that both hCG and 8-Br-cAMP could enhance the expression level of both the Steroidogenic acute regulatory protein (StAR) and mRNA, and increase the activity of extracellular signal-regulated kinase1/2 (ERK1/2) significantly depending on stimulating time. However, the effect of 8-Br-cAMP was more significant than that of hCG. While appending the inhibitor of Protein Kinase A (PKA) to Leydig cells in culture, the expression level of StAR protein, mRNA and the activity of ERK1/2 began to drop significantly, but the level of StAR mRNA could still be detectable. While appending the inhibitor of MAPK (PD98059), the expression level of StAR protein and mRNA declined significantly. These results infer that at the beginning of hCG stimulation, hCG increases the level of StAR protein by cAMP-PKA. With prolonged stimulating time, hCG increases the level of StAR protein through cAMP-PKA-ERK1/2.
 
To identify the effect of leptin on adipocyte, preadipocyte was isolated from male dairy calves and cultured in a monolayer; 5 μg·L−1 bovine leptin were added in culture liquid when the cell differentiated into adipocytes. The result showed that leptin decreased the deposition of triglyceride (TG) and increased the levels of hormone sensitive lipase (HSL) mRNA in cells. At the same time, leptin suppressed the levels of endogenous leptin mRNA, and the levels of leptin receptor (Ob-R) mRNA were raised significantly. It indicated that leptin may induce more fat metabolism directly. Keywordsleptin-fat metabolism-adipocyte
 
PCR-SSCP analysis was used to detect polymorphic sites in chicken adipocyte fatty acid binding protein (A-FABP) gene. Six Chinese local breeds, Beijing-You chicken, Dwarf chicken, Taihe silky chicken, Chongrenma chicken, Xiayan chicken, Luyuan chicken and an introduced foreign breed, Arbor Acre broiler, were used as test populations. Three PCR-SSCP loci were detected. Statistical results showed that frequencies of genotypes and alleles were significantly different in the test populations. Sequence analysis revealed that C → T, G → A, and C → T transitions were responsible for the polymorphisms. Some fat-related traits such as body weight, content of intramuscular fat (IMF) and percentage of abdominal fat (AFP) were measured in Dwarf chickens and male Beijing-You chickens. We found out that chicken quality was significantly related to different genotypes in these two populations.
 
The effects of additional leptin on the long type receptor (Ob-Rb mRNA) for adipocytes of new born calf were tested by means of competitive reverse transcription polymerase chain reaction (RT-PCR). A sample of fine monolayer adipose cells were first obtained and recombination leptins of calf (5 ng/mL · 12 h) were added. No additive was adopted as tester in the adipose cell. Total RNA was determined at 4, 12, 24, 36, 48 and 72 h, and duplicated three times in every treatment in the single factor duplicating test. The result, compared with the group of testers, was that the quantity of Ob-Rb mRNA in adipose cell cultures was also significantly higher (P<0.01) at the beginning stage. Following this tendency, the quantity was gradually lower with cultured time going on in 12–24 h, and the quantity was in stable level (P > 0.05) from 48 to 72 h. It was shown that leptin could improve the level of expression of Ob-Rb in cultured adipose cells of new born calf within a definite time.
 
Immunization protocol of mice with various OVA-ECMS formulations 
The seed of the Momordica cochinchinensis (Lour.) Spreng as a traditional Chinese medicine has been utilized in China for more than 1 200 years. It is traditionally used for the treatment of inflammatory swelling, scrofula, tinea, diarrhea as well as suppurative skin infections such as sore, carbuncles, furuncles and boils in both humans and animals. In this study, an extract from Cochinchina momordica seeds (ECMS) is evaluated for its adjuvant effect and safety. The results suggest that when co-administered with ECMS in Balb/c mice, ovalbumin (OVA, 10 µg) may induce significantly higher specific antibody production than OVA used alone (P < 0.05). Analysis of antibody isotypes indicates that the ECMS can promote the production of both IgG1 and IgG2a, but favor the IgG2a. Splenocyte proliferative responses to concanavalin A, lipopolysaccharides or OVA are significantly higher in mice immunized with OVA mixed with ECMS than immunized with OVA alone or mixed with aluminum hydroxide (P < 0.05). No local reactions and negative effects on the body weight gain occurred after the injection of OVA mixed with various amounts of ECMS in mice. Therefore, the ECMS is safe for injection and can be used as a potential vaccine adjuvant biasing the production of IgG2a in mice.
 
The adaptation of plants to stressed environments depends greatly upon the metabolic level of antioxidant systems within their bodies. Among the enzymatic antioxidant systems, the AsA-GSH cycle occupies a vital place and has become a hot research field in recent years. The AsA-GSH cycle can directly scavenge H2O2 produced in plants on one hand, and the antioxidants AsA and GSH produced in the cycle can also scavenge other species of active oxygen by means of additional pathways on the other hand. Environmental conditions and exogenous formulations can alter the oxidative and reductive status in plants and mediate the metabolic level of the AsA-GSH cycle within a certain range, thus regulating the resistance of plants to stresses. The present paper reviews the advances in research on the AsA-GSH cycle with respect to horticultural crops, so as to provide some beneficial reference for further studies.
 
Rice stripe virus (RSV), the type member of the genus Tenuivirus, is one of the most economically important pathogens of rice and is repeatedly epidemic in China, Japan and Korea. The latest achievements of the studies on the biological functions of virus-encoded proteins, pathogenicity differentiation and genetic diversity of virus, virus-plant host interactions and management of virus were reviewed. The current problems encountered during studies and some approaches for further research were discussed. KeywordsRice stripe virus-achievements-biological functions of virus-encoded proteins
 
The pear (Pyrus spp.) is one of the most important temperate fruit crops. The technique of adventitious shoot regeneration from leaves is considered to be one of the shortcuts in the research on pear genetic modification and cellular engineering, which, however, has not been widely used. As the regeneration frequency of pear leaves is usually very low, the research on adventitious shoot regeneration from pear leaves is eagerly needed. In this experiment, the factors affecting shoot and bud regeneration from the leaves of ‘Zhongli 1’ pear were studied, and an efficient protocol for shoot regeneration was established. The results showed that different types of basic media, different combinations of plant growth regulators, leaf placement on medium, periods of dark culture and the use of silver nitrate (AgNO3) on culture media all significantly affected the adventitious shoot regeneration frequency of ‘Zhongli 1’ pear. The details are as follows: (1) Among three kinds of basic media, NN69 was better for ‘Zhongli 1’ shoot regeneration, followed by half (½) MS, while full MS had no effect on shoot regeneration; (2) Thidiazuron (TDZ) was better than 6-benzylaminopurine (6-BA) for ‘Zhongli 1’ regeneration, with an optimal concentration of 1.5 mg · L−1, and the regeneration rate under this concentration could reach 85%, with 2.72 buds per leaf. 0.5 mg · L−1 indole-3-butyric acid (IBA), which induced a higher regeneration frequency, was a better choice for pear regeneration compared with 0.3 mg · L−1 naphthaleneacetic acid (NAA). Among the different combinations of plant growth regulators, TDZ + IBA was better for inducing high regeneration frequency; (3) The abaxial surface of leaves touching the medium was beneficial for leaves to uptake nutrients from the medium, and because of that, the regeneration frequency of leaves was significantly higher than that of leaves touching the medium with their adaxial surfaces (obverse side of leaf); (4) Dark culture was necessary for bud regeneration, and the best duration for dark culture of ‘Zhongli 1’ pear was 21 days; (5) The addition of 1.0 mg · L−1 AgNO3 into the culture medium could promote adventitious shoot regeneration significantly. A high adventitious shoot regeneration frequency was obtained in this research, which will be beneficial for further research on efficient and stable in vitro plant regeneration systems and genetic modification of pear.
 
The pear (Pyrus spp.) is one of the most important temperate fruit crops. A complete protocol for adventitious shoot regeneration was developed from the leaves of four pear varieties grown in vitro: Abbe Fetel, Yali, Packham’s Triumph and Aikansui, and the Chinese rootstock variety Duli. Shoot explants were collected from the field and cultured in vitro in Murashige and Skoog (MS) media supplemented with 1.0 mg·L−1 6-benzylaminopurine (BA) and 0.1 mg·L−1 indole-3-butyric acid (IBA). After four weeks, leaf explants of all 5 varieties grown in vitro were excised and cultured in MS media supplemented with 0.0 mg·L−1, 0.2mg·L−1, 0.5 mg·L−1, 1.0 mg·L−1 and 2.0 mg·L−1 naphthaleneacetic acid (NAA) and 5.0 mg·L−1 BA or with 1.0 mg·L−1, 2.0 mg·L−1 and 4.0 mg·L−1 thidiazuron (TDZ). The cultures were maintained in darkness for 21 days for shoot induction in the shoot induction medium (IM), then transferred to the shoot expression medium (EM) in 1.0 mg·L−1 TDZ without any auxins and kept in a growth room at (25±2)°C under a 16/8 h light/dark photoperiod regime for 8 weeks. Finally, the shoots were transferred to the MS shoot elongation medium (SEM) supplemented with 0.2 mg·L−1 BA, 0.1 mg·L−1 IBA and 0.2 mg·L−1 gibberellic acid (GA3). A combination of TDZ and NAA had a significant effect on the number of shoot regenerations in all 5 tested varieties. The maximum mean number of shoots and maximum number of shoots per leaf obtained from Yali variety were 11.8 (P⩽0.001) and 22, followed by Aikansui with 6.6 (P⩽0.001) and 4.6, and Duli with 8 (P⩽0.001) and 12, all arising from the combination of 0.2 mg·L−1 NAA with 1.0 mg·L−1 TDZ. For Packham’s Triumph and Abbe Fetel, the maximum mean number of shoots and maximum number of shoots per leaf were 5.6 (P⩽0.001), 4.8 and 8 (P⩽0.001), and 11, respectively, from the combination of NAA (1.0 mg·L−1) and TDZ (2.0 mg·L−1). Abbe Fetel was the only variety which produced significantly higher adventitious shoots from the two different combinations of 1.0 mg·L−1 NAA and 5.0 mg·L−1 BA (P⩽0.05), and 2.0 mg·L−1 NAA and 5.0 mg·L−1 BA (P⩽0.01). Some of the most prominent problems associated with shoot proliferation and regeneration were also observed and discussed in this paper.
 
This review article is based on different aspects of wheat breeding for drought tolerance. Drought is regarded as one of the most serious threats to agriculture in Pakistan. Therefore, breeding for drought tolerance must be given top priority. Here, we try to study various options available to wheat breeders exploring the underlying mechanisms of drought tolerance. The progress made in conventional and non-conventional (molecular) based approaches with potential findings and constraints are reviewed in this article. Equipped with such information, it will be possible for breeders to further explore the mysteries of drought tolerance and to select genotypes with an improved yield under water-deficit conditions. Keywordsbreeding–drought–tolerance–wheat
 
Superoxide dismutases (SODs) play an important role in catalyzing the conversion of O2 − to H2O2, which can reduce the amount of harmful reactive oxygen specie (ROS) generated by the adverse environments, and alleviate the damage to plants. As one class of SODs, CuZnSODs have vital functions in preventing the ROS-generated cell damage and the death in aerobically growing organisms. In this study, two novel CuZnSOD genes in wheat, referred to TaSOD1.1 and TaSOD1.2 were identified, cloned and characterized. TaSOD1.1 and TaSOD1.2 were 780 bp and 1121 bp, respectively, predicting all to encode 201 amino acids. A 45-aa length of transit peptide at the N-terminal and a 79-aa conserved CuZn-SOD domain were respectively located in TaSOD1.1 and TaSOD1.2. Phylogenetic analysis indicated that the query SODs, most of CuZnSODs, could be classified into four subgroups. Compared with the control (CK), the abundance of TaSOD1.1 transcripts did not change under drought, salt, low and high temperature conditions, but the TaSOD1.2 transcripts were strongly induced by the above abiotic stresses, which was in accordance with the elevated SOD activities in leaves in the above stress treatments to some extent, suggesting its involvement in the plant’s acclimation and tolerance to the above abiotic stresses by possibly reducing the amount of the harmful ROS from enhancement of the SOD activity.
 
In this paper, seed morphology and effects of pre-sowing treatments were studied. Matured seeds of the species were collected from healthy trees in the National Botanical Garden, Bangladesh, and treated with five pre-sowing treatments. The average length, breadth and thickness were found to be 0.56±0.03 cm, 0.44±0.009 cm and 0.26±0.008 cm in Albizia richardiana King and Prain, and 1.32±0.02 cm, 0.55±0.04 cm and 0.11±0.002 cm in Lagerstroemia speciosa L., respectively. Germination was carried out in polybags with a mixture of topsoil, coconut husk compost, coarse sand and fine sand in a ratio of 3:4:1:1. Results revealed that the germination rates of seeds in different pre-sowing treatments were significantly increased compared to those in cold-water treatment in both species. The highest germination rate was found to be 96% in hot-water treatment followed by 87%, 83% and 49% in treatments with scarification, H2SO4 and control in A. richardiana, respectively. However, the highest germination rate (79%) was found in H2SO4 treatment followed by 64%, 62% and 25% in treatments with hot water, scarification and control in L. speciosa, respectively. The lowest germination (35% in A. richardiana and 20% in L. speciosa) was found in cold-water treatment in both cases. Analysis of variance (ANOVA) showed the significant difference among the treatments for both species. It is concluded that hot-water treatment is recommended for seed germination of both species in rural Bangladesh. Keywordsseed dormancy-seed-coat-pericarp- Albizia richardiana - Lagerstroemia speciosa
 
Field determination of nitrous oxide emission amount in freeze-thaw stressed soils 
Freeze-thaw event often occurs in regions at mid-high latitude and high altitude. This event can affect soil physical and biological properties, such as soil water status, aggregate stability, and microbial biomass and community structure. Under its effects, the bio-indicators of soil microbes including the kinds and quantities of some specific amino sugars may vary, and the process and intensity of soil nitrogen transformation may change, which can result in an increase in nitrous oxide (N2O) production and emission, making the soil as the major source of N2O emission. This paper summarizes the research progress on the aspects mentioned above, and suggests further research directions on the theoretical problems of soil N2O production and emission under the effects of freeze-thaw event.
 
Premature senescence at the late developmental stage occurs frequently in cotton (Gossypium hirsutum L.) production in North China. It is desirable to develop elite cotton cultivars with non-premature senescence and high photosynthetic capacity. In this study, cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis was employed to identify the genes that are related to senescence in cotton. Using 64 primer combinations, about 3000 cDNA fragments were generated, and among them 42 had a markedly up-regulated expression pattern with the leaf growth progression. Based on cloning, sequencing, and Blast search analysis, it was determined that 24 TDFs with putative known biologic functions could be classified into several major categories, such as signal transduction, transcription regulation, stress-responsive, primary and secondary metabolism, nutrients recycling, photosynthesis, cell wall biosynthesis, and senescence-related. TDF31, TDF32 and TDF33, with high similarity to the senescent-regulating genes MAP kinase 9 (MKK9) and non-yellowing protein 1(NYE1) from Arabidopsis and bean senescence-associated receptor-like kinase (SARK) could play possible roles in responding or modulating the leaf senescence in cotton. Therefore, leaf senescence in cotton is a complicated network involving many biological processes. Some putative genes with important modulation functions in regulating or responding to the senescence need to be further analyzed. Keywordscotton (Gossypium hirsutum L.)-senescence-cDNA-AFLP-gene expression-senescence-related transcript-derived fragments (TDFs)
 
Genetic diversity among 95 Chinese upland cottons with Fusarium and/or Verticillium wilts resistance was estimated using Amplified Fragment Length Polymorphism (AFLP) and Simple Sequence Repeat (SSR) markers. Twenty EcoRI-MseI AFLP and 19 SSR primers with polymorphism were selected to perform the fingerprinting. The results showed that 20 AFLP primer pairs produced a total of 1 480 major bands among 95 genotypes, and 214 were polymorphic bands. The number of total bands per primer pair ranged from 47 to 109, with an average of 74.0. The polymorphism information content (PIC) values for the 20 primer pairs varied from 0.01 (E-ACT/M-CAT) to 0.24 (E-ACA/M-CTA), and the average value was 0.09. Nineteen SSR primers generated 89 DNA bands, of which 61 were polymorphic. The total number of alleles per locus varied from 3 to 8, with an average of 4.7. The average PIC value for the SSR amplification products was 0.69. Genetic similarity estimates for the entire data set ranged from 0.978 to 0.998 based on AFLP and SSR bands. It was proved that the close genetic relationship and narrow genetic diversity existed in the tested cultivars. The clustering patterns could not be correlated to the geographic origin, the pedigree and common parentage of the cultivars.
 
An efficient and stable cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis system for Chinese jujube was established and successfully used for the studies of related stoneless gene difference expression in Ziziphus jujuba Mill. ‘Wuhejinsixiaozao’ fruit. Several main factors influencing cDNA-AFLP analysis were studied, including the preparation and purification of cDNA, restriction and ligation of cDNA, the preamplification reaction, selective amplification reaction, electrophoresis on denaturing polyacrylamide gels, and sliver staining. The results indicated that the total RNA extracted by modified SDS method was pure, complete, and suitable for reverse transcription to cDNA. Restriction digestion of cDNAwas performed by using two restriction enzymes, around 150 ng DNA digested with three units of EcoRI and MseI enzymes, respectively, and incubated at 37°C for 5 h. The digested cDNA fragment was diluted 5 times and used as templates for preamplification, and the preamplification products were diluted 10 times and used as templates for selective amplification. The selective amplification fragments were subjected to PAGE electrophoresis and silver staining. By cDNA-AFLP analysis, it acquired three transcript-derived fragments (TDFs), DC1, DC5, and DC9, related with stoneless gene of Z. jujuba Mill. ‘Wuhejinsixiaozao’ fruit. KeywordsChinese jujube-cDNA-AFLP-stoneless gene-difference expression
 
The genetic diversity of ten Robinia pseudoacacia L. populations collected from China was analyzed by amplified fragment length polymorphism (AFLP) technique using ten primer combinations. A total of 752 amplified bands were obtained, among which 352 (46.8%) were polymorphic. At species level, the percentage of polymorphic loci (P) was 49.87%, the Shannon’s information index (I) was 0.2160, and the mean Nei’s gene diversity index (H) was 0.1403. At population level, P = 25.47%, I = 0.1381, and H = 0.0927. The genetic diversity within populations was higher than that among populations. The coefficient of gene differentiation among populations within species (Gst) was 0.390, which indicated that gene differentiation was mainly within the population, and between populations, it accounted for 33.90% of the total variation. Gene flow (Nm) between the populations was 0.975, suggesting that the gene exchange between populations was small. The UPGMA cluster analysis showed that the ten populations were divided into three major groups, and most individuals from the same population were clustered together. There was no significant correlation between the genetic diversity parameters (D, I N , P, Ne, H, and I) and geographic and climatic factors (longitude, latitude, annual mean temperature, and annual mean precipitation). The results provide useful information about the level of genetic diversity, and it has a wide application prospect in Robinia pseudoacacia L. utilization and breeding in China.
 
Soil-borne diseases of wheat are getting more and more serious in the wheat/maize rotation growing system in northern China. A multifunctional microorganic strain called B1514 was found to have an inhibitory effect against major pathogens of winter wheat soil-borne diseases, have the ability to decompose maize straw, and have the ability to utilize the straw for multiplication. The strain was processed into bacterial agent HAD-1. Field experiments were conducted from 2008 to 2010 to test the control effect of HAD-1 on the major wheat soil-borne diseases, on decomposing ability to maize straw, and on reproductive capacity. Results showed that HAD-1 had significant control effects on sharp eyespot, take-all, and root rot on wheat. The control efficacy at wheat jointing stage was 59.63% to 72.59%, 57.64% to 59.29%, and 54.48% to 63.25%, respectively. The yield loss decreased by 8.67% to 11.70%. The population numbers of the strain B1514 increased 2.68×107−4.83×107 times during the wheat growing season. HAD-1 significantly accelerated the decomposition rate of maize straw in the soil. The decomposition rate increased by 18.7% to 24.3% during wheat growing season. KeywordsStraw amendment–bacterial agent–winter wheat–soil-borne disease–bio-control
 
In order to elucidate the significance and related mechanisms of microbial agents in modulating the growth of broilers, one-day-old Avian broilers were employed to investigate the effect of microbial agents on body weight, daily gain and feed efficiency at various stages. The birds in the experimental groups were given salmonella pullorum then fed with antibiotics to counteract it. The results showed that the average broiler weight of the oral microbial agent group at the age of 40 days was significantly increased by 16.58% from 1520 g to 1772 g (P < 0.05). The feed conversion efficiency was decreased from 2.21 to 1.82 (P < 0.01). In the experimental group fed with microbial agents, microscopic observation revealed that the intestinal villi increased in number, length and orderliness. The intestinal wall became thickened. The glands in the intestine were developed, which would be beneficial to nutrient absorption. The effect of oral microbial agents was identical to that due to antibiotics. It was also observed that Lactobacillus dominated the cecal microorganisms in broilers.
 
Through the outdoor potted plant trials, the allelopathic potential of Populus tomentosa was tested against its species in the growth, chlorophyll content, and photosynthetic and chlorophyll fluorescence characteristics with aqueous extracts (0.01, 0.02, 0.05, and 0.1 g·mL−1) obtained from leaves at different individual ages (1, 20, and 45 years old). The results showed that seedling height, basal diameter, fresh and dry weights, quantity of chlorophyll, the ratio of chlorophyll a/b, net photosynthetic rate (P n ), stomatal conductance (G s ), transpiration rate (T r ), efficiency of primary conversion of light energy of PSII (F v /F m ), potential activity of PSII (F v /F 0), and photochemical quenching (q P ) of the seedlings gradually decreased with the increase of extract concentration of all three ages when compared with the controls. The older the P. tomentosa used for extract preparation, the greater the percentage declined in the aforementioned parameters. Moreover, at the four concentrations used, there was a significant difference between treatments with the extracts from 1- and 45-year-old plants (except for q P ), but occasionally, the effects were not obvious between the 1- and the 20-year-old plants, or the 20- and 45-year-old plants. The intercellular CO2 concentration (C i ) treated with the extracts from the 1-year-old decreased at the lowest concentration, whereas it increased at higher concentrations. The C i treated with aqueous leaf extracts from the 20-year-old decreased at the lower concentrations and increased to similar levels to that of the control at the higher concentrations. C i was always close to control levels in 45-year-old extract treatments. All the aqueous leaf extracts of P. tomentosa at all ages caused an increase of the initial fluorescence (F 0 ). The older P. tomentosa used for the preparation of aqueous leaf extracts caused a greater percentage decline in F 0 . The nonphotochemical quenching (q N ) increased significantly at lower concentrations of all P. tomentosa extracts, whereas it decreased significantly at higher concentrations. It seemed that aqueous leaf extracts from P. tomentosa were harmful to the photosynthetic structure of its own seedlings, inhibited seedling growth, and led to an eventual decrease of biomass. Extracts from older P. tomentosa leaves had more negative effects on the seedling growth of poplar. The effects on photosynthesis are the more important mechanism of the allelopathy of poplar.
 
A total of 436 goat samples from twenty-six populations were scanned for single nucleotide polymorphisms (SNPs) in 5′UTR of goat MSTN gene using sequencing and the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP). The deletion of TTTTA found in 5′UTR of goat MSTN gene was conserved in different species and might be a unique mutation in goats. The Foreign Group and the Boer Goat backcrossed offspring had the highest and smallest genetic diversity of this mutation respectively, and also with the smallest and highest heterozygosity deficiency respectively. The genetic diversity of this mutation for the South Group of Chinese indigenous goat breeds was higher than that of the North Group, and the South Group had the smaller heterozygosity deficiency than the North Group. The estimated marginal means based on the modified population marginal mean and pairwise comparison between significant pairs showed that there was a trend that genotype AA had a significant effect on body weight and size from birth to four-month old (P<0.05 or P<0.01). It could be inferred that the deletion of TTTTA in 5′UTR of goat MSTN gene had a significant effect on body weight and size.
 
Top-cited authors
ALI BAGHERZADEH
  • Islamic Azad University Mashhad Branch
Mohammad Reza Mansouri Daneshvar
  • Shakhes Pajouh Research Institute
Fa-Bo Chen
  • Yangtze Normal University
Dongsheng Yu
  • Chinese Academy of Sciences
Xuezheng Shi
  • Chinese Academy of Sciences