THE EFFECT OF LIGHT AND DARK PERIODS ON THE PRODUCTION OF ETHYLENE FROM WATER-STRESSED WHEAT LEAVES
THE EFFECT OF LIGHT AND DARK PERIODS ON THE PRODUCTION OF ETHYLENE FROM WATER-STRESSED WHEAT LEAVES
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DOI：
10.1007/bf00384099
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发表时间：
1981-01-01
期刊：
影响因子：
4.3
通讯作者：
WRIGHT, STC
中科院分区：
文献类型：
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作者：
WRIGHT, STC
光抑制大幅度（高达88%）的生产乙烯诱导的水分胁迫在离体小麦叶片和芽的完整植株。相对少量的乙烯从非胁迫叶片发出的光也被抑制，但在较小的程度上（高达61%）。在水分胁迫的叶片中，乙烯产生的光抑制程度被证明是与叶龄有关的;从嫩叶（6天）的乙烯扩散量被光抑制52%，而在老叶（9天），它被抑制85%。以前的研究表明，6-苄基腺嘌呤（BA）的应用程序的叶子萎蔫前一天大大增加了乙烯扩散的量从叶子萎蔫后（例如8倍），并在较小程度上做IAA和GA 3的应用程序。脱落酸（阿坝）处理减少乙烯的产生量。在这些早期的实验中，乙烯收集在黑暗或近黑暗的条件下举行的叶片，所以在本研究中，这些生长调节剂（10-4摩尔L-1的解决方案）在黑暗和光照条件下的活动进行了比较。它们对乙烯散发保持相同的相对活性（即，BA > IAA > GA 3>水分对照>阿坝）。然而，由于光的抑制作用，从所有处理产生的乙烯的绝对量总是在黑暗中比在光下高得多（通常约6倍的差异）。当水分胁迫的叶片在暗室中保持4 1/2小时，然后转移到光下时，光处理对乙烯生物合成的一个有趣的影响发生。非常出乎意料的是，乙烯生产速率没有立即下降，而是继续以暗速率生产（即，无光抑制）持续2小时以上，然后速率开始下降，如果用BA喷洒叶片，则持续更长的时间，超过4 1/2小时。可以预见的是，将叶子置于光照下，然后转移到黑暗中，立即或很快以黑暗的速度产生乙烯。乙烯前体的生物合成可能需要一个专性黑暗阶段。这些研究的可能影响乙烯在植物中的生存作用在水分胁迫期间进行了讨论。
Light inhibited substantially (up to 88%) the production of ethylene induced by water stress in excised wheat leaves and from the shoots of intact plants. The relatively small amounts of ethylene emanating from non-stressed leaves were also inhibited by light but to a smaller degree (up to 61%). In water-stressed leaves the degree of light inhibition of ethylene production was shown to be related to the age of the leaves; the amounts of ethylene diffusing from young leaves (6 days old) was inhibited 52% by light whereas in older leaves (9 days old) it was inhibited by 85%. Previous studies showed that application of 6-benzyladenine (BA) to leaves a day before wilting greatly increases the amount of ethylene diffusing from the leaves following wilting (e.g. 8-fold), and to smaller degrees do applications of IAA and GA3. Abscisic acid (ABA) treatment reduces the amount of ethylene produced. In these earlier experiments the ethylene was collected from leaves held under dark or near-dark conditions, so in the present study the activities of these growth regulators (10-4 mol l-1 solutions) under dark and light conditions were compared. They maintained the same relative activities on ethylene emanation (i.e., BA > IAA > GA3 > water controls > ABA) under both light and dark conditions. However, because of the inhibitory effect of light, the absolute amounts of ethylene produced from all treatments were always much higher in the dark than in the light (usually about a 6-fold difference). An interesting effect of light treatment on ethylene biosynthesis occurred when water-stressed leaves were kept in dark chambers for 4 1/2 h and then transferred to light. Quite unexpectedly, instead of the rate of ethylene producton falling immediately, it continued to be produced at the dark rate (i.e., no light inhibition) for over 2 h before the rate began to decline, and for a much longer period in excess of 4 1/2 h) if the leaves were sprayed with BA. Predictably, leaves placed in the light and then transferred to darkness, immediately or very soon produced ethylene at the dark rate. The biosynthesis of an ethylene precursor may require an obligatory dark stage. The possible implications of these studies to a survival role of ethylene in plants during periods of water stress is discussed.