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Scanning Electron Microscopy Investigation of Cytoplasmic Male Sterile Line Rice : Exploring Treatment Effects on Plant Components and their Impact on Hybrid Rice Seed Production
Abstract
In addressing the challenge of inflorescence emergence in cytoplasmic male sterile line (CMS) rice, specifically the CMS A-line, GA3 has conventionally been utilized. However, the high cost of GA3 poses financial constraints for middle-class and marginal farmers. This study aims to identify cost-effective alternatives to GA3 for CMS breeding. Utilizing IR58025A as the A-line and KMR3 as the R-line, obtained from Rice Research Station, Chinsurah, Hooghly, the experiment was conducted following CMS breeding layout design at the Crop Research Farm under the Department of Botany, the University of Burdwan. Various chemicals, including GA3 , penicillin, sulfonamide, and gentamicin, were applied as foliar spray treatments, alongside a control group, during flowering to produce F1 seeds from the A-line in the boro season. The primary objectives include exploring microfeatures of different plant organs such as leaves, stems, androecium, and gynoecium through SEM analysis to evaluate the effectiveness of the diverse treatments. This research contributes valuable insights for rice breeders and the scientific community, offering potential alternatives to GA3 in CMS breeding technology.
... Micro-histological analysis of CMS line rice (IR58025A) using SEM provided further insights into treatment impacts on plant structures. 30 Notably, penicillin treatment induced a marked loosening of the endothecium layer in the androecium and strengthened the gynoecium, promoting a more fibrous and gametophytic structure. These microstructural modifications indicate an enhanced seed set potential, underscoring penicillin's viability in improving F 1 hybrid rice production. ...
Imperfect panicle emergence in Cytoplasmic Male Sterile (CMS) lines is a hindrance for hybrid rice seed (F1) production. In CMS lines 10-15% of spikelets remaining enclosed within the flag leaf. This limits their availability for outcrossing, thereby reducing the efficiency of hybrid rice seed production. To mitigate this issue, the application of gibberellic acid (GA3) is a common practice. However, the high cost of GA3 poses a significant barrier for middle-class farmers involved in hybrid rice seed production. This study aims to identify low-cost chemical alternatives to GA3. We evaluated ten different treatments, including a control, on CMS (A) line rice plants. Our findings indicate that penicillin is the most effective treatment, offering high yield at a reduced cost. According to the yield component, treatment-2 (penicillin) reflected grain yield 71.26 g plant -1 which is highest among all the treatments. Potassium dichromate also performed well in promoting panicle emergence. Characters showing positive and significant correlations among different traits are expected to improve yield and can be selected for further advancement in hybrid rice seed production.
Gibberellic acid (GA3) application after anthesis is an important practice in hybrid rice seed production, and it plays diverse roles in seed quality and seed yield. The main objective of this study was to determine (1) the effects of GA3 application after anthesis on seed vigor and (2) the optimal GA3 dosage applied to Indica hybrid rice seed production. Field experiments of different GA3 dosages (15 g hm−2 and 30 g hm−2, respectively) after anthesis were conducted in 2016 and 2017, and seed vigor parameters, stigma vigor index, and seed yield were determined. We found that significant differences in seed vigor parameters by a standard germination test and a cool germination test were observed among different GA3 dosages after anthesis. Compared with the water spraying treatment, the germination percentage (GP) increased by 2.5–6.3%, and the vigor index (VI) increased by 8.9–19.8% from GA3 application after anthesis, respectively. Moreover, the stigma vigor index of the female parent was enhanced with an increasing GA3 dosage, and there were significant increases (7.5–16.0%) between the water spraying treatment and GA3 spraying treatments. There were positive significant relationships between the VI and stigma vigor index. Additionally, the seed yield of the GA3 application with 30 g hm−2 was 3.9% higher on average than that of the water spraying treatment. Therefore, our study suggests that seed vigor can be increased by GA3 application after anthesis, and GA3 application should be applied at a rate of 30 g hm−2 to improve seed vigor and maintain seed yield in Indica hybrid rice seed production.
We characterized silica structures in the epidermis of rice plant leaves and investigated their physiological functions from optical and mechanical viewpoints. By treating the distribution of silica bodies as a triangular lattice in the xy plane, and performing a theoretical optical analysis on this lattice, we discovered that a reduction in the photonic density of states may inhibit leaves of rice plant from being heated markedly higher than 20 °C. Ladderlike structures in the epidermis were mechanically investigated. These structures are conjectured to inhibit flat leaves from undergoing twisting torsions, which may assist the leaf to absorb sunlight more effectively for photosynthesis.
Many plants take up soluble monosilicic acid from the soil. Some of these plants subsequently deposit it as cell inclusions
of characteristic structure. This article describes the distribution and diversity of opaline silica bodies in monocotyledons
in a phylogenetic framework, together with a review of techniques used for their examination, and the ecology, function and
economic applications of these cell inclusions. There are several different morphological forms of silica in monocot tissues,
and the number of silica bodies per cell may also vary. The most common type is the “druse-like” spherical body, of which
there is normally a single body per cell, more in some cases. Other forms include the conical type and an amorphous, fragmentary
type (silica sand). Silica bodies are most commonly found either in the epidermis (e.g., in grasses, commelinas and sedges)
or in the sheath cells of vascular bundles (e.g., in palms, bananas and orchids). Silica-bearing cells are most commonly associated
either with subepidermal sclerenchyma or bundle-sheath sclerenchyma. Silica bodies are found only in orchids and commelinids,
not in other lilioid or basal monocots. In orchids, silica bodies are entirely absent from subfamilies Vanilloideae and Orchidoideae
and most Epidendroideae but present in some Cypripedioideae and in the putatively basal orchid subfamily Apostasioideae. Among
commelinid monocots, silica bodies are present in all palms, Dasypogonaceae and Zingiberales but present or absent in different
taxa of Poales and Commelinales, with at least four separate losses of silica bodies in Poales.
Conflict/reconciliation between mitochondria and nuclei in plants is manifested by the fate of pollen (viable or nonviable) in the cytoplasmic male sterility (CMS)/fertility restoration (Rf) system. Through positional cloning, we identified a nuclear candidate gene, RETROGRADE-REGULATED MALE STERILITY (RMS) for Rf17, a fertility restorer gene for Chinese wild rice (CW)-type CMS in rice (Oryza sativa L.). RNA interference-mediated gene silencing of RMS restored fertility to a CMS plant, whereas its overexpression in the fertility restorer line induced pollen abortion. The mRNA expression level of RMS in mature anthers depended on cytoplasmic genotype, suggesting that RMS is a candidate gene to be regulated via retrograde signaling. We found that a reduced-expression allele of the RMS gene restored fertility in haploid pollen, whereas a normal-expression allele caused pollen to die in the CW-type CMS. RMS encodes a mitochondrial protein, 178 aa in length, of unknown function, unlike the majority of other Rf genes cloned thus far, which encode pentatricopeptide repeat proteins. The unique features of RMS provide novel insights into retrograde signaling and CMS.
ABSTRACT Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by electron microscopy and X-ray microanalysis. A blast-susceptible cultivar, Jinmi, and a partially resistant cultivar, Hwaseong, were grown under a hydroponic culture system with modified Yoshida's nutrient solution containing 0, 50, 100, and 200 ppm of silicon. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamellae, and intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface, with relatively small deposition on stomatal guard cells in silicon-treated plants. Silicon accumulation and epidermal cell wall thickness in leaves were greater in cv. Jinmi than in cv. Hwaseong. However, the thickness ratios of the silicon layers to epidermal cell walls were greater in cv. Hwaseong (53.25 to 93.28%) than in cv. Jinmi (36.58 to 66.54%). Leaf blast severity was lower in cv. Hwaseong than in cv. Jinmi and was significantly reduced in silicon-treated plants of both cultivars. These results suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.
Several distinctive histological features of the stamen, especially of the filament, are described, some of these for the first time: for example, commonness of (a) mesarch xylem maturation, amphicribral bundles or else collateral strands with phloem considerably enveloping the xylem, and clustering of sieve elements of a bundle and their spatial separation from tracheary elements, (b) exclusively helical wall thickenings of tracheary elements and absence of sclerenchyma, (c) open stomata, a weakly developed cuticle, a prominent intercellular-space system, xylem lacunae, and (d) tannins and crystals. Some of the features in category (a) seem related to the nutritional needs of developing pollen grains in the anther. Features in category (b) are directly related to the usual expansion of the stamen, in particular the filament, before and at anthesis. Features in category (c) (and possibly (d)) probably promote a rapid loss of water or a disruption of the water supply to the anther, and therefore might facilitate anther dehiscence (these features could operate either in isolation or in unison). Tannins, crystals, and secretory structures have been implicated in the protection of pollen against predators.
The levels of gibberellin and cytokinin like substances are increased in mungbean (Vigna radiata L. Wilczek) seedlings by penicillin treatment. The possible role of penicillin in regulating the hormone levels in plant
tissues is suggested.
Bamboo is a silicon accumulating plant. In leaves, the major place of silicon (Si) deposition is the epidermis, with the highest concentration of Si in silica cells. In bamboo roots, the deposition of Si is found only in endodermal cell walls. The silicification of leaves and roots was examined in the economically important bamboo plant Phyllostachys heterocycla, using an environmental scanning electron microscope coupled with X-ray microanalysis, as well as gravimetric quantification. The content of Si on a dry weight basis measured by gravimetric quantification was 7.6% in leaves and 2.4% in roots, respectively. Moreover, quantification of EDX data showed high Si impregnation of the inner tangential endodermal walls. Si content in this part of the root endodermal cell walls was even higher than that in the outer leaf epidermal walls, where conspicuous deposition of Si often occurs in grass plants.
Behiry Said, I., Boudiar Ridha, Mansour Elsayed, 2022. Growth regulators improve outcrossing rate of diverse rice cytoplasmic male sterile lines through affecting floral traits
- A Z El Shamey Essam
- Hamad Hassan
- Sh
- S Alshallash Khalid
- A Alghuthaymi Mousa
- Mohamed Ghazy
- M Sakran Raghda
- E Selim Mahmoud
- A A El Sayed Mahmoud
- M Taher
- A Okasha Salah
El Shamey Essam, A.Z., Hamad Hassan, Sh., Alshallash
Khalid, S., Alghuthaymi Mousa, A., Ghazy
Mohamed., Sakran Raghda, M., Selim Mahmoud,
E., El Sayed Mahmoud, A. A, Abdelmegeed Taher,
M., Okasha Salah, A., Behiry Said, I., Boudiar Ridha,
Mansour Elsayed, 2022. Growth regulators improve
outcrossing rate of diverse rice cytoplasmic male
sterile lines through affecting floral traits. Plants. 11:
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Study the Effect of Different Treatments on Hybrid Rice Seed (F 1 ) Production and Assessment of Heavy Metals by Using Atomic Absorption Spectrophotometry. Research
- R Pal
- S Bhattacharyya
- C K Santra
Pal, R., Bhattacharyya, S.S and Santra, C.K. 2023. Study the
Effect of Different Treatments on Hybrid Rice Seed
(F 1 ) Production and Assessment of Heavy Metals by
Using Atomic Absorption Spectrophotometry. Research Journal of Agricultural Sciences. 14 (5):1476-1479.
Breeding behaviour and histological structure of a nondehiscent anther character in Sorghum vulgare
- O J Werbster
- S P Singh
Werbster, O.J. and Singh, S.P. 1964. Breeding behaviour
and histological structure of a nondehiscent anther
character in Sorghum vulgare. Pers. Crop Sci. 4: 656-658.