土壤紧实胁迫对黄瓜叶片光合作用及叶绿素荧光参数的影响

紧实是温室土壤的疲劳症状之一,它对作物的生长、产量及养分吸收均有影响。本试验以容重为指标,用盆栽试验模拟温室土壤的物理疲劳症,研究了土壤紧实胁迫对黄瓜叶片光合作用及叶绿素荧光参数的影响,探讨温室土壤物理疲劳对黄瓜叶片光合作用产生影响的机理。结果表明,土壤紧实胁迫条件下黄瓜叶片的净光合速率（Pn）、气孔导度(Gs)及蒸腾速率(Tr)下降,而胞间CO2浓度（Ci）却增大,最终导致叶片干物质的累积量减少,第一雌花节位降低,果实发育提早。叶片的叶绿素含量减少,光合活性（Fv）、光系统Ⅱ（PSⅡ）反应中心的电子传递活性（Fm/Fo）、光能的最大转化效率（Fv/Fm）及PSⅡ的潜在活性（Fv/Fo）降低以及PSⅡ的光能利用率下降是紧实胁迫条件下黄瓜叶片光合作用减弱的原因。

Effects of soil compaction stress on photosynthesis, chlorophyll fluorescence parameters of cucumber(Cucumis sativus L.)leaves

Soil compaction, one of the fatigue signals of greenhouse soil, affects growth, yield and nutrition absorption of crops grown in greenhouse conditions. In the present study, effects of soil compaction stress were investigated on photosynthesis,chlorophyll fluorescence parameters of cucumber(Cucumis sativus L.) leaves. Results showed that net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) decreased, while intercellular CO₂ concentration (C_i) increased in cucumber plants grown under soil compaction stress. These changes further resulted in reduction of specific leaf weight (SLW), lowering of node position for the first female flower bud initiation and thus early development of fruits. Decreased photosynthesis of leaves was associated with chlorophyll content, electron transport activity (Fm/Fo), maximal photochemical transformation efficiency (Fv/Fm) and potential activity (Fv/Fo) of photosystem Ⅱ reaction center（PSⅡ）in cucumber plants grown under soil compaction stress.