Ordentlich A, Linzer R A, Raskin I
AgBiotech Center, Cook College, Rutgers University, P.O. Box 231, New Brunswick, New Jersey 08903-0231.
Plant Physiol. 1991 Dec;97(4):1545-50. doi: 10.1104/pp.97.4.1545.
The alternative respiratory pathway dissipates most of the chemical energy of respiratory substrates as heat. We have shown that this heat can be quantified by microcalorimetry and is a measure of alternative pathway activity in vivo. The alternative pathway is known to increase in aged potato (Solanum tuberosum) slices and in chill-stressed leaves. Aging of potato slices for 24 hours was accompanied by an almost fourfold increase in the rate of heat evolution. This heat increase was resistant to KCN but could be blocked by an alternative pathway inhibitor, salicylhydroxamic acid (SHAM). In cucumber (Cucumis sativus) leaves subjected to chilling stress (between 4 and 16 degrees C), the rate of heat evolution was inversely related to temperature. As in aged potato slices, the increased rate of heat evolution in cucumber leaves was blocked by SHAM, but not by KCN. Nitrogen or the combination of SHAM and KCN blocked most of the heat evolution in both aged potato slices and chill-stressed cucumber leaves. Calorimetric measurements of the alternative pathway corresponded to respiration measurements performed using an oxygen electrode.
交替呼吸途径将呼吸底物的大部分化学能以热量的形式耗散。我们已经表明，这种热量可以通过微量量热法进行量化，并且是体内交替途径活性的一种度量。已知交替途径在老化的马铃薯（Solanum tuberosum）切片和冷胁迫的叶片中会增加。将马铃薯切片老化24小时后，热释放速率几乎增加了四倍。这种热量增加对氰化钾有抗性，但可被交替途径抑制剂水杨羟肟酸（SHAM）阻断。在遭受冷胁迫（4至16摄氏度）的黄瓜（Cucumis sativus）叶片中，热释放速率与温度呈负相关。与老化的马铃薯切片一样，黄瓜叶片中增加的热释放速率被SHAM阻断，但未被氰化钾阻断。氮气或SHAM与氰化钾的组合阻断了老化马铃薯切片和冷胁迫黄瓜叶片中的大部分热释放。交替途径的量热测量结果与使用氧电极进行的呼吸测量结果一致。
