ECOPHYSIOLOGICAL SIGNIFICANCE OF CO2-RECYCLING VIA CRASSULACEAN ACID METABOLISM IN TALINUM-CALYCINUM ENGELM (PORTULACACEAE)
ECOPHYSIOLOGICAL SIGNIFICANCE OF CO2-RECYCLING VIA CRASSULACEAN ACID METABOLISM IN TALINUM-CALYCINUM ENGELM (PORTULACACEAE)
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DOI：
10.1104/pp.86.2.562
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发表时间：
1988-02-01
期刊：
影响因子：
7.4
通讯作者：
WANG, WZ
中科院分区：
文献类型：
--
作者：
MARTIN, CE;HIGLEY, M;WANG, WZ
高水平的变化，在气体交换特性和CAM循环的程度被发现在相同和不同的个人的Talinum calycinum Engelm。采集自密苏里州[美国]的岩石露头。CO2同化的差异主要与地上部CO2电导率的差异相关，而不是地上部CO2浓度。如前所述，CAM酸波动是明显的，在浇水良好的植物表现出C3气体交换模式（CAM循环），也在干旱胁迫的植物气孔关闭，或几乎如此，白天和黑夜（CAM空转）。干旱胁迫还导致气孔迅速关闭，在干旱期间保持水分。最大CO2吸收速率发生在低于35 ℃。较高的温度引起的CO2同化和电导下降，而拍摄内部CO2浓度保持不变。在30 ℃以上的温度下，植物水分利用效率严重降低。C.组织酸波动的苹果酸浓度的变化的结果。CAM循环可能保存的水量计算值约为白天水分损失的5%至44%。因此，CAM循环可能是一个重要的适应减少水分流失的多年生肉质植物生长在浅土壤上的岩石露头。
High levels of variability in gas exchange characteristics and degree of CAM-cycling were found in the same and different individuals of Talinum calycinum Engelm. collected from rock outcrops in Missouri [USA]. Differences in CO2 assimilation were mostly correlated with differences in shoot conductance to CO2 not shoot internal CO2 concentration. As found previously, CAM acid fluctuations were evident in well-watered plants exhibiting C3 gas exchange patterns (CAM-cycling) and also in drought-stressed plants with stomata closed, or nearly so, day and night (CAM-idling). Drought stress also resulted in rapid stomatal closure, conserving water during droughts. Maximal CO2 uptake rates occurred below 35.degree. C; higher temperatures induced decreases in CO2 assimilation and conductance while shoot internal CO2 concentrations remained similar. Plant water-use-efficiency was severely curtailed at temperatures above 30.degree. C. Tissue acid fluctuations were the result of changes in malic acid concentrations. Calculations of the amount of water potentially conserved by CAM-cycling yielded values of approximately 5 to 44% of daytime water loss. Thus, CAM-cycling may be an important adaptation minimizing water loss by perennial succulents growing in shallow soil on rock outcrops.