Ecophysiological differences between three mangrove seedlings (Kandelia obovata, Aegiceras corniculatum, and Avicennia marina) exposed to chilling stress
Ecophysiological differences between three mangrove seedlings (Kandelia obovata, Aegiceras corniculatum, and Avicennia marina) exposed to chilling stress
复制标题
低温胁迫下三种红树幼苗（秋茄、桐花树和白骨壤）的生态生理差异
DOI：
10.1007/s10646-015-1488-7
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发表时间：
2015-10-01
期刊：
影响因子：
2.7
通讯作者：
Cheng, Hao
中科院分区：
文献类型：
--
作者：
Peng, Ya-Lan;Wang, You-Shao;Cheng, Hao
虽然不同物种红树林的抗寒能力差异很大，但其生理机制尚不清楚。研究了低温胁迫对3种红树幼苗(秋茄、桐花树和白骨壤)叶片形态、光合色素、活性氧(ROS)、丙二醛(MDA)和几种抗氧化剂的影响。结果表明，与滨海相思相比，倒卵相思和相思具有较轻的冷害、较低的冷害发生率和较高的存活率。三种红树植物的叶绿素(Chls)含量均有下降，其中以滨海海棠的下降幅度最大。ROS含量显著增加(过氧化氢，H202；羟基自由基，OH.)在冷害下，倒卵木耳的H_2O_2含量降低，恒定的OH中心点水平降低，丙二醛的瞬时含量增加。随着胁迫时间的延长，各红树植物体内的脯氨酸和水溶性蛋白质含量均呈现出相似的上升趋势，其中角果海棠的上升幅度最大，而可溶性蛋白质的上升幅度相对较大。随着胁迫时间的延长，所有红树林的过氧化氢酶活性均显著下降，倒卵叶红树的下降幅度最小。3种红树植物的抗坏血酸(ASA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性均有不同程度的提高，其中倒卵果红树的增加幅度最大。这些结果表明，主成分分析证实，红树林的耐冷性与抗氧化剂的效率有关。在氧化胁迫过程中，倒卵圆藻中的AsA、APX和POD可能比其他两个物种在控制氧化胁迫中起着重要作用。此外，角果沙打旺的抗寒性比海滨沙打旺更强，这可能与其较高的脯氨酸积累量有关。结果表明，酶和非酶类抗氧化剂(POD、APX、ASA、Pro和CAR)在清除红树林中过量的ROS中起着关键作用。对这些逆境反应基因的深入研究将有助于从分子水平上更好地理解植物的抗寒机制。
Although the cold-resistant ability of mangroves varies greatly with species, the physiological mechanism remains unclear. The chilling stress effects on morphological changes, photosynthetic pigments, reactive oxygen species (ROS), malondialdehyde (MDA) and several antioxidants, were studied in leaves of three mangrove seedlings (Kandelia obovata, Aegiceras comiculatum and Avicennia marina). Results showed that both K. obovata and A. corniculatum exhibited lighter chilling damage, lower chilling injury rates and higher survival rates compared to A. marina. Reductions of chlorophylls (Chls) were observed in all the three mangroves, and the highest was detected in A. marina. Significant increases in content of ROS (hydrogen peroxide, H202; hydroxyl radicals, OH.) and MDA were observed in both A. marina and A. corniculatum, whereas chilling stressed K. obovata showed a decrease in H2O2 content, constant OH center dot level and instantaneous increase of MDA. The contents of proline and water-soluble protein exhibited similar stress-time dependent increases in all mangroves, while A. corniculatum showed the highest increase of proline and relatively higher increase of water-soluble protein. The catalase activities significantly decreased with stress time in all mangroves, while K obovata showed the least reduction. An increase in ascorbic acid (AsA) content and activities of superoxide dismutase, peroxidase (POD), and ascorbate peroxidase (APX) were also detected in all the three mangroves, while K. obovata showed the highest increases. These results indicate that chilling-tolerance of mangroves is associated with the efficiency of antioxidants, as confirmed by principal component analysis. The AsA, APX and POD in K obovata may play more important role in control of oxidative stresses than those in the other two species. Furthermore, the higher cold-resistance of A. corniculatum compared to A. marina may be partly associated with its higher proline accumulation. The results indicate that enzymatic and non-enzymatic antioxidants (POD, APX, AsA, proline and Car) play key roles in scavenging of excess ROS in mangroves. Further studies focusing on these stress-responsive genes will enable better understanding of the cold-resistance mechanism from molecular level.