Interaction between photon flux density and elevated temperatures on photoinhibition in Alocasia macrorrhiza
Interaction between photon flux density and elevated temperatures on photoinhibition in Alocasia macrorrhiza
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DOI：
10.1007/s004250050314
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发表时间：
1998-06-01
期刊：
影响因子：
4.3
通讯作者：
Pearcy, RW
中科院分区：
文献类型：
--
作者：
Königer, M;Harris, GC;Pearcy, RW
研究了光照和温度对光系统II能量转换效率[O-PSII=(Fm‘-Fs)/Fm’]、遮荫驯化海芋色素组成和耐热性的影响。叶盘暴露于强光(HL；1600 mU·m(-2)·s(-1))或弱光(L1；20 mU·m(-2)·s(-1))和30~49℃的恒温下3h，所有HL处理都导致O-PSII迅速而严重的下降。在HL治疗后的2小时恢复期(LL，25摄氏度)。可以区分快速恢复阶段和缓慢恢复阶段。经过HL和30℃处理的叶片在HL和45℃下暴露3小时后，O-PSII完全恢复，而O-PSII在45℃下暴露3小时后，O-PSII的下降不那么严重，不到1小时就完全恢复。在LL条件下，49℃的温度需要引起O-PSII的不可逆下降，然后第二天就会坏死。链霉素对暴露于HL和35-45℃的O-PSII椎间盘的还原和恢复程度没有影响，但部分抑制了暴露于HL和30℃的O-PSII的恢复。链霉素导致在LL和49℃时O-PSII的下降更严重，完全抑制了恢复。在治疗或恢复期间，链霉素对叶黄素循环色素的转化没有影响。在3-h HL处理(0.270-0.346)后，无论暴露温度如何，所有叶盘中的环氧化状态都大致相同。玉米黄质在2小时恢复期后被反向转化为紫黄质，只有在HL和30℃下暴露的叶盘中才能观察到玉米黄质的反向转化。遮荫下大根海参叶片的耐热性为49.0+/-0.7℃(用荧光法测定)，这与暴露在LL下的叶盘发生损伤的温度一致。然而，在HL下，发生坏死的临界温度低得多(42摄氏度)。短时间(<；20min)微温处理可提高大根草遮荫叶片的耐热性。
The effects of light and elevated temperatures on the efficiency of energy conversion in PSII [O-PSII = (Fm'-Fs)/Fm'], pigment composition and heat tolerance of shade-acclimated Alocasia macrorrhiza were investigated. Leaf discs were exposed for 3 h to high light (HL; 1600 mu mol photons.m(-2).s(-1)) or low light (LL; 20 mu mol photons.m(-2).s(-1)) and a series of constant temperatures ranging from 30 to 49 degrees C. All HL treatments led to rapid and severs decreases in O-PSII. During the 2-h recovery period (LL, 25 degrees C) following the HL treatments. fast and slow recovery phases could be distinguished. Leaf discs that had experienced HL and 30 degrees C recovered completely while no recovery of O-PSII was seen after a 3-h exposure to HL and 45 degrees C. A 3-h exposure to 45 degrees C at LL led to a less severe decrease in O-PSII and complete recovery was accomplished after less than 1 h. Under LL conditions a temperature of 49 degrees C was necessary to cause an irreversible decrease in O-PSII, followed by necrosis the next day. Streptomycin had no effect on the degree of reduction and recovery in O-PSII discs exposed to HL and 35-45 degrees C, but partially inhibited recovery in discs exposed to HL and 30 degrees C. Streptomycin led to a more severe decrease in O-PSII at LL and 49 degrees C and completely inhibited recovery. Streptomycin had no effect on the conversion of the xanthophyll-cycle pigments during the treatment or the recovery. The epoxidation state was roughly the same in all leaf discs after a 3-h HL treatment (0.270-0.346) irrespective of the exposure temperature. The back-conversion of zeaxanthin into violaxanthin after a 2-h recovery period was only seen in leaf discs that had been exposed to HL and 30 degrees C. The thermotolerance of shade A. macrorrhiza leaves of 49.0 +/- 0.7 degrees C (determined by fluorescence) coincided with the temperature at which damage occurred in leaf discs exposed to LL. However, under HL the critical temperature under which necrosis occurred was much lower (42 degrees C). The thermotolerance of A. macrorrhiza shade leaves could be increased by a short exposure (< 20 min) to slightly elevated temperatures.