Ascertain the Effect of PEG and Exogenous ABA on Rice Growth at Germination Stage and Their Contribution to Selecting Drought Tolerant Genotypes
In this study, the effect of exogenous ABA on radicle and plumule growth at germination stage was investigated, compared with PEG osmotic stress culture condition and the consistency between genotypic variation in exogenous ABA and PEG sensitivity at germination stage and in water deficit treatment at reproductive stage in the field was evaluated. Fifteen rice ( Oryza sativa L.) cultivars with different drought resistant ability were studied, 7.8x10-6 mol L-1 ABA and 30% PEG1500 (-1.1 MPa) were used to culture the germinated seeds for 5 days and the length, fresh and dry weight of radicle and plumule were measured and compared with normal condition (distilled water). In the field water stress experiment, drip irrigation was served for all plots every other day and water was discontinued for 14 days when the flag leaf reached stage 0 for the main stems in the plot. In this study, both PEG and ABA applied could inhibit the growth of plumule and radicle and significant difference existed among genotypes in the reduction rate of plumule and radicle. While for most of the tested genotypes, the response to ABA was similar to PEG and water stress in the field as well, which indicated the genotypes variation and ranking for the treatment with ABA based on the reduction rate of radicle and plumule growth parameters and with PEG based on reduction rate of plumule growth were rather similar to the same genotypes in field water deficit experiment based on the yield reduction rate. So exogenous ABA at germination stage could be and even more effective compared with PEG to quantify the drought resistance among genotypes in rice.
Available from: Veena Pandey
- "division (Jaleel et al, 2009). It impairs the germination of rice seedlings (Jiang and Lafitte, 2007; Swain et al, 2014) and reduces number of tillers (Mostajeran and Rahimi-Eichi, 2009; Ashfaq et al, 2012; Bunnag and Pongthai, 2013) and plant height (Sarvestani et al, 2008; Ashfaq et al, 2012; Bunnag and Pongthai, 2013; Sokoto and Muhammad, 2014). A common adverse effect is the reduction in biomass production (Farooq et al, 2009a, 2010). "
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ABSTRACT: Rice (Oryza sativa L.) is an important food crop and requires the largest amount of water as
compared to any other crop throughout its life cycle. Hence, water related stresses cause severe threat
to rice production. Drought is a major challenge limiting rice production. It affects rice at morphological
(reduced germination, plant height, plant biomass, number of tillers, various root and leaf traits),
physiological (reduced photosynthesis, transpiration, stomatal conductance, water use efficiency,
relative water content, chlorophyll content, PSII activity, membrane stability, carbon isotope
discrimination and abscisic acid content), biochemical (accumulation of osmoprotectant like proline,
polyamines, antioxidants) and molecular (altered expression of genes which encode transcription
factors and defence related proteins) levels and thereby affecting its yield potential. To facilitate the
selection or development of drought tolerant rice cultivars, a thorough understanding of the various
mechanisms that govern the yield of rice under water stress condition is a prerequisite. Thus, this review
is focused mainly on recent information about the effects of drought on rice crop, its responses as well
as adaptation mechanisms to drought stress.
Rice Science 04/2015; 22(3). DOI:10.1016/S1672-6308(14)60289-4
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ABSTRACT: We studied the physiological responses to abscisic acid (ABA) when 2-year-old potted plants of kiwifruit (Actinidia deliciosa) were grown under moisture stress. Leaves treated with 60μM exogenous ABA through various means had less severe damage when
water was limiting, and sprayed plants showed relatively greater drought resistance. This indicates that ABA improves tolerance
in kiwifruit, reducing membrane permeability and enhancing the activities of antioxidant enzymes, e.g., peroxidase (POD),
catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR). Exposure to ABA led
to higher levels of antioxidants, such as ABA and glutathione (GSH), while altering the amounts of endogenous hormones—ABA,
indole-3-acetic acid (IAA), and Gibberellin (GA)—and organic oxalate, malate, and citrate in the leaves. Although daily applications
of ABA were more effective than a single spray event, the effect of treatment, i.e., avoiding tissue damage and increasing
plant resistance, was more apparent on Day 4 than on Day 6. No difference in response was apparent between control plants
(regular irrigation) and those sprayed with ABA on Day 4 of the drought period.
Plant Growth Regulation 05/2010; 64(1):63-74. DOI:10.1007/s10725-010-9537-y · 1.67 Impact Factor
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ABSTRACT: Due to key role of ABA in drought tolerance, it was envisaged to develop a method for extraction and quantification of Abscisic Acid (ABA) and to isolate a ABA responsive and water deficit stress inducible gene from rice. A new analytical method which ensures the integrity of ABA during extraction, clean-up and estimation, was developed. ABA was quantified at different developmental stages of immature seeds and leaves. ABA content in leaves increases when a plant is exposed to water deficit stress but it decreases as the leaves approach maturity. ABA concentration also increases as developing seeds attain maturity. An ABA responsive gene of 264 bp was isolated which shows induced expression under water deficit stress. The gene has two domains, one belonging to aspartate aminotransferase super family of pyridoxal phosphate dependent enzymes and the other showing similarity with Major Facilitator Super family (MFS) of secondary transporters that include uniporters, symporters and antiporters. ABA content, extracted by a simplified methodology and estimation by HFLC, is found to be correlated with the degree to which the stress alters plant water status which results in the expression of the identified gene.
American Journal of Plant Physiology 03/2011; 6(3):144-156. DOI:10.3923/ajpp.2011.144.156
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