Evidence that the induction of crassulacean acid metabolism by water stress in Mesembryanthemum crystallinum (L.) involves root signalling
Evidence that the induction of crassulacean acid metabolism by water stress in Mesembryanthemum crystallinum (L.) involves root signalling
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DOI：
10.1046/j.1365-3040.1997.d01-50.x
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发表时间：
1997-12
影响因子：
7.3
通讯作者：
P. Eastmond;J. D. Ross
中科院分区：
文献类型：
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作者：
P. Eastmond;J. D. Ross
本研究旨在探讨结晶型中胚轴的根系是否具有较强的抗逆性。在水分胁迫期间触发景天酸代谢(CAM)的诱导。通过让根部周围的土壤干燥来剥夺灌溉良好的植物的水分，会导致叶片相对含水量(RWC)和叶肉细胞膨胀压力的每日损失增加。根的相对含水率也有所下降。随后，植物表现出CAM光合作用的生理特征(即叶片可滴定酸度的昼夜波动和夜间净CO2固定)。当植物的根系平均分配到两个土室和一半缺水时，植物表现出CAM的生理特性，而叶片RWC含量和叶肉细胞膨压没有预先变化。只有根部水分胁迫部分的相对含水量有所降低。这些数据表明，在水分胁迫植物中，叶片水分关系的每日变化比充分灌溉植物中观察到的更大，对于触发CAM表达并不是必不可少的。结晶草的根部很可能感受到土壤水分有效性的降低，并将这一信息传递到叶片，从而触发从C3到CAM光合作用的转变。
The aim of this study was to investigate whether the root system of Mesembryanthemum crystallinum (L.) plays a role in triggering the induction of crassulacean acid metabolism (CAM) during water stress. Depriving well-irrigated plants of water, by allowing the soil surrounding the roots to dry, caused increased daily losses in leaf relative water content (RWC) and mesophyll cell turgor pressure. The RWC of the roots also declined. Subsequently plants exhibited physiological characteristics of CAM photosynthesis (i.e. diurnal fluctuations in leaf titratable acidity and nocturnal net CO 2 fixation). When the root system of plants was divided equally between two soil compartments and one half deprived of water, plants exhibited physiological characteristics of CAM without prior changes in leaf RWC content or mesophyll cell turgor pressure. Only the RWC of the water-stressed portion of the roots was reduced. These data suggest that in water-stressed plants daily changes in leaf water relations greater than those observed in well-irrigated plants, are not essential to trigger CAM expression. It is probable that a reduction in soil water availability can be perceived by the roots of M. crystallinum and that this information is conveyed to the leaves triggering the transition from C 3 to CAM photosynthesis.