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采用1/2Hoagland营养液培养,研究了低氧胁迫下24-表油菜素内酯(EBR)对黄瓜幼苗叶片光合特性及多胺含量的影响.结果表明:低氧胁迫下黄瓜幼苗的净光合速率(Pn)、气孔导度(gs)、蒸腾速率(Tr)、胞间CO2浓度(Ci)显著下降,而叶绿素含量显著提高,幼苗生长受抑;低氧胁迫显著提高了黄瓜幼苗叶片的腐胺(Put)、亚精胺(Spd)、精胺(Spm)、多胺(PAs)含量和Put/PAs,但降低了(Spd+Spm)/Put.低氧胁迫下,外源EBR不仅显著提高了黄瓜幼苗的Pn、gs、Tr及叶绿素含量,也显著提高了黄瓜幼苗叶片的游离态Spm、结合态Spd、Spm及束缚态Put、Spd、Spm含量,促进了PAs的进一步积累,且降低了Put/PAs,提高了(Spd+Spm)/Put.可见,外源EBR调节了黄瓜幼苗内源多胺含量及形态的变化,维持了较高的光合性能,促进了叶面积和干物质量的显著增加,缓解了低氧胁迫对黄瓜幼苗的伤害.
The effects of 24-epibrassinolide (EBR) on the photosynthetic characteristics and polyamine content of cucumber seedling leaves under hypoxia stress were studied using 1 / 2Hoagland nutrient solution culture.The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO2 concentration (Ci) decreased significantly while chlorophyll content increased significantly and seedling growth was inhibited. Hypoxia stress significantly increased putrescine in cucumber seedling leaves Spd, Spm, PAs and Put / PAs, but decreased (Spd + Spm) / Put. Exogenous EBR was not only significantly increased under hypoxia stress The contents of Pn, gs, Tr and chlorophyll of cucumber seedling also significantly increased the contents of free Spm, bound Spd, Spm and bound Put, Spd and Spm in cucumber seedling leaves, promoted the accumulation of PAs and decreased the contents of Put / PAs increased (Spd + Spm) / Put. It can be seen that exogenous EBR regulates endogenous polyamine content and morphological changes in cucumber seedlings, maintaining high photosynthetic performance and promoting a significant increase of leaf area and dry matter , Alleviate the damage of cucumber seedlings under hypoxia stress.