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Accueil du site → Doctorat → Chine → 2020 → Effects of Drought Stress on Germination and Growth of Rapeseed and Mechanism of Seed Priming to Improve Drought Resistance

Huazhong Agricultural University (2020)

Effects of Drought Stress on Germination and Growth of Rapeseed and Mechanism of Seed Priming to Improve Drought Resistance

Mohammad Nauman Khan;

Titre : Effects of Drought Stress on Germination and Growth of Rapeseed and Mechanism of Seed Priming to Improve Drought Resistance

Auteur : Mohammad Nauman Khan;

Grade : Doctoral Dissertation 2020

Université : Huazhong Agricultural University

Résumé partiel
The edible oil production in China is highly dependent on the successful production of rapeseed.However,the excessive occurrence of autumn drought caused obstacles to the germination and normal growth of rapeseed.Drought stress is the main reason for crop failure.Water stress encumbers the rapeseed growth and development primarily by oxidative alteration to biological membranes and interrupted tissue water status.Seedling tolerance to water stress is vital for better crop development through the entire period under drought stress condition.Priming seed is an approach through which seeds are exposed to numerous unfavorable situations to confer stress variation in seedlings germinating and growing under stressful conditions.However,its physiological mechanism research is not systematic.The present study aimed to elucidate how seed priming affected rapeseed germination,early seedling growth,seed yield and quality by conducting a series of incubator,pot and field experiments.The main findings are summarized below.(1)Drought stress inhibited germination and early seedling growthTo better predict about the adaption of rapeseed to drought stress,the current study explored the presumed roles of enzymatic,non-enzymatic antioxidants and osmolytes in improving rapeseed drought-tolerance.The comparative analysis in terms of germination and early seedling growth of six rapeseed cultivars was assessed under normal(0.00 MPa)and osmotic stresses(-0.1,-0.2,-0.3,-0.4,and-0.5 MPa simulated by polyethylene glycol 6000).Subsequently,based on the process of germination and early seedling growth,Shenguang 127(SG 127)and Zhongyou 36(ZY 36)were chosen as drought-tolerant and-sensitive rapeseed varieties.The results indicated that drought stress rigorously hindered germination and early seedling growth of rapeseed cultivars.On the other hand,SG 127 exhibited less reduction in seedling growth paralleled with ZY 36.SG 127 revealed lower levels of hydrogen peroxide(H2O2),lipids peroxidation(MDA),electrolyte leakage(EL %)and less reduction in chlorophyll(Chl)content than ZY 36.The drought-tolerance of SG 127 may be correlated with enhanced activities of enzymatic(superoxide peroxidase,catalase,and dismutase),non-enzymatic antioxidants(ascorbic acid,glutathione),more accumulation of proline ;total soluble sugar and total soluble protein.

Mots clés : Rapeseed(Brassica napus L.); drought stress; seed priming; seed yield; seed quality;

Présentation (CNKI)

Page publiée le 5 juin 2021