Comparison of thermostability of PSII between the chromatic and green leaf cultivars of Amaranthus tricolor L.
Comparison of thermostability of PSII between the chromatic and green leaf cultivars of Amaranthus tricolor L.
复制标题
三色苋彩色叶品种和绿叶品种PSII的热稳定性比较。
DOI：
10.1007/s11099-009-0080-x
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发表时间：
2009-12-01
期刊：
影响因子：
2.7
通讯作者：
Peng, C. -L.
中科院分区：
文献类型：
--
作者：
Shu, Z.;Shao, L.;Peng, C. -L.
In the present study, we investigated the antioxidative potential in leaves of the chromatic (CC) versus green (GC) Amaranthus tricolor L. under moderate high-temperature stress at 45A degrees C. Before heat stress, CC had significantly higher levels of betacyanins [about 3.2 mg g(-1)(FM)] than the green [1.8 mg g(-1)(FM) (p < 0.01), while similar chlorophyll (Chl) content [about 2 mg g(-1)(FM)] was observed between both cultivars. After exposure to high temperature (45A degrees C) for 6 days, betacyanins in leaves of CC were remarkably increased (about 2 times of that in control samples grown at 30A degrees C). In contrast, betacyanins in GC significantly decreased by 56% in comparison with that of the control. Chl level in CC was higher than that in GC after heat stress for 6 days. Flavonoids and total phenolics in both cultivars were increased, but much more in CC. Significantly less H2O2 accumulation was observed in the leaves and stems of CC than in those of GC under heat stress. Interestingly, much stronger circadian oscillation in fluorescence was observed in both cultivars after treatment at 45A degrees C, which suggested that heat stress stimulates endogenous rhythms of photosystem II (PSII). Under moderate high-temperature stress, Chl fluorescence parameters F-v/F-m (maximum quantum yield of PSII), q(P) (coefficient of photochemical quenching), I broken vertical bar(PSII) (effective PSII quantum yield), and ETR (electron transport rate) exhibited a gradual decrease, NPQ (nonphotochemical quenching) showed a slight increase followed by a gradual decline, whereas F-o (minimum fluorescence of a dark-adapted leaf) increased continuously. In contrast to GC, after 120 h of high-temperature treatment, CC exhibited significantly lower Fo level, and higher levels of F-v/F-m and NPQ. It is clear that PSII in CC was more stable than that in GC. The results indicate that betacyanins are an effective antioxidant, and probably contribute greatly to the higher thermal stability of PSII and higher tolerance to heat stress.
