Zhang Run Hua, Li Jun, Guo Shi Rong, Tezuka Takafumi
College of Horticulture Science, Nanjing Agricultural University, Nanjing 210095, China.
Photosynth Res. 2009 Jun;100(3):155-62. doi: 10.1007/s11120-009-9441-3. Epub 2009 Jun 9.
The effects of 10 mM putrescine (Put) treated by spraying on leaves on growth, chlorophyll content, photosynthetic gas-exchange characteristics, and chlorophyll fluorescence were investigated by growing cucumber plants (Cucumis sativus L. cv. ChangChun mici) using hydroponics with or without 65 mM NaCl as a salt stress. Salt stress caused the reduction of growth such as leaf area, root volume, plant height, and fresh and dry weights. Furthermore, net photosynthesis rate (P(n)), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)), and transpiration rate (T(r)) were also reduced by NaCl, but water use efficiency (WUE; P(n)/T(r)) showed a tendency to be enhanced rather than reduced by NaCl. However, Put alleviated the reduction of P (n) by NaCl, and showed a further reduction of C (i) by NaCl. The reduction of g(s) and T(r) by NaCl was not alleviated at all. The enhancement of WUE by NaCl was shown to have no alleviation at day 1 after starting the treatment, but after that, the enhancement was gradually reduced till the control level. Maximum quantum efficiency of PSII (F(v)/F(m)) showed no effects by any conditions based on the combination of NaCl and Put, and in addition, kept constant values in plants grown in each nutrient solution during this experimental period. The efficiency of excitation energy capture by open photosystem II (PSII) (F(v)'/F(m)'), actual efficiency of PSII (Phi(PSII)), and the coefficient on photochemical quenching (qP) of plants with NaCl were reduced with time, and the reduction was alleviated till the control level by treatment with Put. The F(v)'/F(m)', Phi(PSII), and qP of plants without NaCl and/or with Put showed no variation during the experiment. Non-photochemical quenching of the singlet excited state of chlorophyll a (NPQ) showed quite different manner from the others as mentioned above, namely, continued to enhance during the experiment.
通过水培黄瓜植株（黄瓜品种长春密刺），研究了叶面喷施10 mM腐胺（Put）对其生长、叶绿素含量、光合气体交换特性及叶绿素荧光的影响，水培分为添加或不添加65 mM NaCl作为盐胁迫两种情况。盐胁迫导致黄瓜植株生长减缓，如叶面积、根体积、株高以及鲜重和干重降低。此外，NaCl还降低了净光合速率（P(n)）、气孔导度（g(s)）、胞间CO₂浓度（C(i)）和蒸腾速率（T(r)），但水分利用效率（WUE；P(n)/T(r)）却呈现出升高而非降低的趋势。然而，Put缓解了NaCl对P(n)的降低作用，并使NaCl导致的C(i)进一步降低。NaCl对g(s)和T(r)的降低作用完全未得到缓解。处理开始后第1天，NaCl对WUE的升高作用未得到缓解，但此后这种升高作用逐渐降低至对照水平。基于NaCl和Put的组合条件，PSII的最大量子效率（F(v)/F(m)）未受任何影响，此外，在此实验期间，生长于每种营养液中的植株该值均保持恒定。NaCl处理植株的开放光系统II（PSII）捕获激发能的效率（F(v)'/F(m)'）、PSII的实际效率（Phi(PSII)）以及光化学猝灭系数（qP）随时间降低，而Put处理使这种降低缓解至对照水平。未添加NaCl和/或添加Put的植株的F(v)'/F(m)'、Phi(PSII)和qP在实验期间未发生变化。叶绿素a单重激发态的非光化学猝灭（NPQ）表现出与上述其他指标截然不同的变化方式，即在实验期间持续升高。
