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Yangzhou University (2007)

Screening and identification of rice drought indicators

Qiu Jian Liang

Titre : Screening and identification of rice drought indicators

Auteur : Qiu Jian Liang

Grade : Master’s Theses 2007

Université : Yangzhou University

Résumé
Drought is one of the most important environmental factors restricting the crop growth and its yield. Breeding for drought-tolerant variety is the most important way to alleviate yield reduction caused by drought stress. Both conventional and molecular breeding depend largely on the drought-tolerant index, including morphological, physiological and biochemical indexes). Thereby, it is very urgent to screen and identify simple and reliable drought-tolerant indexesIn present study, we tried to find out some useful parameters related to drought tolerance by screening rice plants with different sensitivities to soil drying or osmotic stress (PEG treatment) from theγ-ray (60Co) treated rice populations and by measuring related physiological and biochemical parameters. The main results showed that1. The relative growth rate of new-appeared leaves and root to shoot ratio at the seedling stage were the most direct and simple morphological indexes in screening drought tolerance plants. The more rapid the leaf grows and the higher the root to shoot ratio under osmotic stress, the more tolerant the rice plants. Physiological analysis showed that leaf water potential, SOD activity and leaf proline content were closely related to drought tolerance and considered as the most reliable physiological indexes of drought tolerance. Under drought or osmotic stress conditions, tolerant rice plants usually had a higher leaf water potential, higher SOD activity and higher praline content than drought-sensitive plants.2. To some extent, net photosynthetic rate and CAT activity can also be used as drought resistant indexes. As compared with drought-tolerant plants, drought resistant rice plants usually haa higher net photosynthetic rate and CAT activity under drought stressed condition.3. Our results also indicated that stomatal conductance, Fv/Fm, qP, NPQ, POD activity and ABA content were not the better indexes for screening drought tolerant rice plants, as suggested by many other laboratory.

Mots clés : rice drought resistance growth rate leaf water potential SOD proline

Présentation (Dissertationtopic)

Page publiée le 13 septembre 2014, mise à jour le 8 novembre 2017