| Effects of soil water availability on leaf photosynthetic and drought-tolerant parameters of pear-jujube tree |
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| DOI：10.16302/j.cnki.1000-7601.2015.01.001 |
| Key Words: pear-jujube soil water photosynthesis drought-tolerance |
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| Abstract: |
| Using automatic weighing and irrigation system, three-years-old pear-jujube tree were exposed to suitable soil water condition, medium drought and severe drought, corresponding to 75%±5%, 60%±5%, 45%±5% of field water capacity, respectively, to examine effects of soil water availability on leaf photosynthetic and drought-resistant parameters. Results showed that: (1) Medium drought did not have significant effect on leaf photosynthetic parameters, while severe drought significantly reduced leaf net photosynthetic rate(Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and light use efficiency (LUE), but increased the water use efficiency (WUE) and the stomatal limitation value (Ls). (2) Medium drought did not influence leaf malonaldehyde (MDA) content, but significantly increased catalase (CAT) activity, whereas severe drought significantly increased MDA content, the activity of superoxide dismutase (SOD) and peroxidase (POD), and increased the contents of ascorbic acid (ASA) and glutathione (GSH). However, the increases in activities of SOD and POD and contents of ASA and GSH could not repair the damage of membrane system by severe drought. Hence, medium drought did not cause an abiotic stress for pear-jujube leaves, but severe drought had significant impacts on leaf photosynthetic parameters and membrane system, indicating the necessity of irrigation when severe drought occurs. |
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