高温环境下枣光合特性及相关生理指标日变化

【目的】研究两个枣品种在高温环境下光合特性及相关生理指标的差异。【方法】以10 a生骏枣和伏脆蜜为对象,在吐鲁番田间自然高温条件下,测定光合日变化参数,采集相同部位叶片,测定丙二醛(MDA)、渗透调节物质。【结果】伏脆蜜的净光合速率(P_n)为单峰型;骏枣则呈双峰型,且在12:00有明显的光合午休现象。两品种蒸腾速率(T_r)均呈双峰型,但伏脆蜜的蒸腾速率(T_r)变化更剧烈,在14:00有明显的谷值。两品种的丙二醛(MDA)、脯氨酸(Pro)和可溶性蛋白(SP)含量变化趋势基本一致,其中骏枣的MDA和Pro明显高于伏脆蜜,且MDA含量骏枣较伏脆蜜提前4 h达到最大值。【结论】高温环境下,伏脆蜜无光合午休现象,叶片的净光合速率(P_n)和蒸腾速率(T_r)较骏枣高;骏枣叶片MDA和Pro含量明显高于伏脆蜜,其叶片细胞膜受损比伏脆蜜重。光合特性和生理指标两方面均证明伏脆蜜细胞膜稳定性较强,耐高温能力优于骏枣。

Study on Diurnal Variation of Photosynthetic Characteristics and Related Physiological Indexes of Jujube under High Temperature Environment

【Objective】 To study the differences of photosynthesis and physiological responses to heat stress between two jujube cultivars in the areas of atypical warmth.【Method】The photosynthetic diurnal changes of 10-year-old Fucuimi and Junzao were determined under natural high-temperature conditions in the field of Turpan. Meanwhile, the leaves at the corresponding time were collected to determine the contents of malondialdehyde (MDA), osmoregulation substances in the laboratory. 【Result】The results showed that diurnal variation of net photosynthetic rate(P_n) of Fucuimi was single-peak curve, while that of Junzao was a typical bimodal curve with noon break at 12 o'clock. The Transpiration rate (T_r) of the two cultivars showed a bimodal curve, but Fucuimi changed more drastically, with obvious troughs at 14 o'clock. The trends of MDA, proline (Pro), and soluble protein (SP) content in the two varieties were the same. The MDA and Pro of Junzao were significantly higher than that of Fucuimi. The content of MDA in Junzao reached the maximum value 4 hours earlier than Fucuimi.【Conclusion】In the high temperature areas, Fucuimi didn't have a noon break in photosynthetic, and it's P_n and T_r of the leaves were higher than those of Junzao. The contents of MDA and Pro in the leaves of Junzao were significantly higher than those of Fucuimi. Both photosynthetic characteristics and physiological indexes proved that the cell membrane stability of Fucuimi was stronger than that of Junzao. Fucuimi was more resistant to high temperatures than Junzao.