Chengdu Institute of Biology, Chinese Academy of Sciences, PO Box 416, Chengdu 610041, China.
Tree Physiol. 2010 Dec;30(12):1489-98. doi: 10.1093/treephys/tpq094. Epub 2010 Nov 11.
We investigated sex-related morphological and physiological responses to enhanced UV-B radiation in the dioecious species Populus cathayana Rehd. Cuttings were subjected to two UV-B radiation regimes: ambient (4.5 kJ m⁻² day⁻¹) and enhanced (12.5 kJ m⁻² day⁻¹) biologically effective UV-B radiation for one growing season. Enhanced UV-B radiation was found to significantly decrease the shoot height and basal diameter and to reduce the leaf area, dry matter accumulation, net photosynthesis rate (P(n)), chlorophyll a/b ratio (Chl a/b) and anthocyanin content. Enhanced UV-B radiation also increased chlorophyll pigment, leaf nitrogen, malondialdehyde and abscisic acid (ABA) content, superoxide dismutase and peroxidase activities and UV-B-absorbing compounds. No significant effects of enhanced UV-B radiation were found on biomass allocation, gas exchange (except for P(n)), photochemical efficiency of photosystem II or water use efficiency. Moreover, different sensitivity to enhanced UV-B radiation between males and females was detected. Under enhanced UV-B radiation, males exhibited significantly higher basal diameter and leaf nitrogen, and lower Chl a/b, ABA content, UV-B-absorbing compounds, as well as less decrement of leaf area and dry matter accumulation than did females. However, no significant sexual differences in these traits were found under ambient UV-B radiation. Our results suggest that males may possess a greater UV-B resistance than do females, with males having a more efficient antioxidant system and higher anthocyanin content to alleviate UV-B penetration stress than females.
我们研究了增强的 UV-B 辐射对雌雄异株物种毛白杨无性系形态和生理的影响。无性系在两种 UV-B 辐射条件下生长一个生长季：环境（4.5 kJ m⁻² day⁻¹）和增强（12.5 kJ m⁻² day⁻¹）生物有效 UV-B 辐射。研究发现，增强的 UV-B 辐射显著降低了 shoot height 和 basal diameter，并减少了 leaf area、干物质积累、净光合速率（P(n)）、叶绿素 a/b 比（Chl a/b）和花青素含量。增强的 UV-B 辐射还增加了 chlorophyll pigment、leaf nitrogen、丙二醛和脱落酸（ABA）含量、超氧化物歧化酶和过氧化物酶活性以及吸收 UV-B 的化合物。增强的 UV-B 辐射对生物量分配、气体交换（除 P(n)外）、光系统 II 的光化学效率或水分利用效率没有显著影响。此外，还检测到增强的 UV-B 辐射对雌雄个体的不同影响。在增强的 UV-B 辐射下，雄性的 basal diameter 和 leaf nitrogen 显著较高，Chl a/b、ABA 含量、吸收 UV-B 的化合物以及 leaf area 和干物质积累的减少幅度较低，而雌性则较低。然而，在环境 UV-B 辐射下，这些性状没有表现出显著的性别差异。研究结果表明，雄性可能比雌性具有更强的抗 UV-B 能力，雄性具有更有效的抗氧化系统和更高的花青素含量，以减轻 UV-B 穿透胁迫。
