Wang Tian, Wang Suping, Guo Shirong, Sun Yanjun
College of Horticulture, Nanjing Agricultural University, China.
Ying Yong Sheng Tai Xue Bao. 2006 Sep;17(9):1609-12.
With water culture, this paper studied the effects of exogenous spermidine (Spd) on the net photosynthetic rate (Pn), intercellular CO2 concentrations (Ci), stomatal conductance (Gs), transpiration rate (Tr), apparent quantum yield (phi c), and carboxylation efficiency (CE) of cucumber seedlings tinder hypoxia stress. The results showed that the Pn decreased gradually under hypoxia stress, and reached the minimum 10 days after by 63. 33% of the control. Compared with that of hypoxia-stressed plants, the Pn after 10 days application of exogenous Spd increased 1.25 times. A negative correlation (R2 = 0.4730 - 0.7118) was found between Pn and Ci. Gs and Tr changed in wider ranges, which decreased under hypoxia-stress, but increased under hypoxia-stress plus exogenous Spd application. There was a significant positive correlation between Gs and Tr (R2 = 0.7821 - 0.9458), but these two parameters had no significant correlation with Pn; Hypoxia stress induced a decrease of phi c and CE by 63.01% and 72.33%, respectively, while hypoxia stress plus exogenous Spd application made phi c and CE increase by 23% and 14%, respectively. The photo-inhibition of cucumber seedlings under hypoxia stress was mainly caused by non-stomatal limitation, while exogenous Spd alleviated the hypoxia stress by repairing photosynthesis system.
采用水培法，研究了外源亚精胺（Spd）对黄瓜幼苗在低氧胁迫下净光合速率（Pn）、胞间CO₂浓度（Ci）、气孔导度（Gs）、蒸腾速率（Tr）、表观量子产量（φc）和羧化效率（CE）的影响。结果表明，低氧胁迫下Pn逐渐降低，处理10 d时降至最低，仅为对照的63.33%。与低氧胁迫植株相比，外源Spd处理10 d后Pn提高了1.25倍。Pn与Ci呈负相关（R² = 0.4730 - 0.7118）。Gs和Tr变化幅度较大，低氧胁迫下降低，低氧胁迫加外源Spd处理后升高。Gs与Tr呈显著正相关（R² = 0.7821 - 0.9458），但这两个参数与Pn无显著相关性；低氧胁迫使φc和CE分别降低63.01%和72.33%，低氧胁迫加外源Spd处理使φc和CE分别提高23%和14%。低氧胁迫下黄瓜幼苗的光抑制主要由非气孔限制引起，外源Spd通过修复光合系统缓解了低氧胁迫。
