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Physiological response of soybean methyl jasmonate protective effect of drought adaptation

Author: WangHui
Tutor: BiYuRong
School: Central University for Nationalities
Course: Botany
Keywords: drought stress glutathione methyl jasmonate soybean
CLC: S565.1
Type: Master's thesis
Year: 2011
Downloads: 73
Quote: 3
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Abstract

In the present study, the soybean (Glycine max) seedlings (’Jindou 21’) were subjected to PEG-6000 for drought stress to observe the physiological responses to drought stress. Also, the protective roles of methyl jasmonate (JA-Me) were investigated under drought stress. These studies can provide theoretical and experimental evidences for improving soybean tolerance to drought stress. The main results are as follows:1. The relative ion leakage markedly increased and the relative water content significantly decreased in the soybean seedlings under 10%, 15%, and 20% PEG treatments for 24 h, respectively. The recovery experiment showed that the soybean seedlings could resist 15% PEG stress for 24h treatment. The further results demonstrated that the contents of proline and soluble sugar increased with the increasing time under 15% PEG treatment. The antioxidant enzyme (SOD, APX, CAT, POD) activities also increased markedly, and reached their maximum at 24 h. The similar profile was observed in both the total and the cytosol G6PDH activity, and the cytosol G6PDH activity increased to 230% of the control under 15% PEG treatment for 24 h.2. The exogenous application of JA-Me could effectively relieve the effects of PEG on the relative ion leakage and relative water content in the soybean seedlings, and 0.25μM JA-Me is the optimal concentration. The APX activity increased significantly under JA-Me+PEG treatment in comparison with the PEG treatment alone, however, SOD, CAT and POD activities had almost no marked changes. Under JA-Me+PEG treatment for 48-72 h, JA-Me could inhibit the decrease of GSH content induced by PEG; and the activities of GR and GPX showed the similar changes. The exogenous JA-Me also reduced the reactive oxygen species (ROS) content in soybean seedlings under drought stress. To further confirm the roles of JA-Me under drought stress, salicylhydroxamic acid (SHAM, an inhibitor of JA metabolic process) was used. The results showed that SHAM could effectively abolish the effect of JA-Me under drought stress.3. The chlorophyll content, maximum photochemical efficiency of PSII (Fv/Fm), efficiency of excitation capture of PSII (Fv’/Fm’), photochemical fluorescence quenching efficiency (qP), apparent photosynthetic rate (Photo.), stomatal conductance (Gs) and transpiration rate (Tr) in the soybean seedlings decreased markedly under 15% PEG treatment for 24 h. The Non-photochemical quenching (NPQ) increased under 15% PEG treatment for 0-24 h, however, it decreased for 48-72 h. The exogenous JA-Me application could inhibit the decrease of the above parameters in soybean seedlings under drought stress. SHAM could effectively abolish the effect of JA-Me.In conclusion, the exogenous JA-Me application can relieve the harm to soybean seedlings under drought stress. It might play an important role in improving soybean tolerance to drought mainly by regulating the antioxidant system related to glutathione recycle under drought stress.

Physiological response of soybean methyl jasmonate protective effect of drought adaptation

Abstract

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