光周期与光质对栎属幼苗生长及叶绿素荧光的影响

Effects of Photoperiod and Light Quality on Seedling Growth and Chlorophyll Fluorescence Kinetics of Quercus L.

[目的]通过探讨光周期与光质对栎属(Quercus L.)植物幼苗生长及对幼苗叶片光化学反应的影响机制,为栎属植物育苗壮苗及人工辅助更新提供科学参考。[方法]以栎属植物幼苗(3栓皮栎种源+1蒙古栎+1短柄枹栎)为研究对象,通过调控人工LED光源的方式,研究3种光周期(日夜时长分别为10 h/14 h,14 h/10 h,18 h/6 h)、3种红光/远红光比(R:FR分别为0.83±0.04、1.37±0.04、4.69±0.04)对栎属植物幼苗的相对生长速率及叶绿素荧光参数的影响。[结果](1)随着光周期延长,总体上栎属植物幼苗叶片的F_(v)/F_(o)、F_(v)/F_(m)、Ψ_(o)、φE_(o)、P_(IAbs)增加,M_(o)、V_(i)、V_(j)、ABS/RC、DI_(o)/RC、φD_(o)降低,其中栓皮栎幼苗在中光周期下M_(o)、V_(i)、V_(j)最高,Ψ_(o)、φE_(o)最低;在种间水平上,短柄枹栎和栓皮栎较之蒙古栎对光周期的响应更强烈,缩短光周期会显著降低短柄枹栎的F_(v)/F_(m)及RGR,延长光周期显著提高了栓皮栎和短柄枹栎的RGR,但蒙古栎的F_(v)/F_(m)及RGR对光周期的响应均不显著。在种源水平,延长光周期显著提高了栓皮栎南方种源(YN)的F_(v)/F_(o)和F_(v)/F_(m),且栓皮栎3个种源的RGR均随着光周期延长呈增加趋势。(2)栎属植物幼苗总体对光质比处理不敏感。光质比对3个栎属种间和栓皮栎不同种源间的RGR以及能量分配参数、量子产额参数影响不显著。(3)光质比与光周期对RGR存在显著交互效应。在中光周期下,幼苗表现出明显的避阴反应,即低光质比下RGR最高,且显著高于正常光质比和高光质比。[结论]幼苗对光周期和光质比响应存在种内和种间差别:栓皮栎南方种源对光周期变化响应更加敏感,短柄枹栎和栓皮栎较之蒙古栎对光周期的响应更强烈;栎属植物幼苗总体对光质比处理不敏感,幼苗只在特定光周期下有避阴反应。

[Objective]To study the growth and photochemical mechanism of leaves in Quercus L.seedlings responding to photoperiod and light quality in order to provide reference for seedling cultivation and artificial assisted regeneration of Quercus L.[Method]The growth parameter and chlorophyll fluorescence parameters of Quercus spp.seedlings(3 Q.variabilis provenances+1 Q.mongolica+1 Q.glandulifera)under three photoperiods(the lengths of light and dark were 10 h/14 h,14 h/10 h,18 h/6 h,respectively)and three red-far red light ratios(R:FR=0.83±0.04,1.37±0.04,4.69±0.04,respectively)were investigated.[Result](1)At the species'level,the F_(v)/F_(o),F_(v)/F_(m),Ψ_(o),φE_(o) and P_(IAbs) increased,while M_(o),V_(i),V_(j),ABS/RC,DI_(o)/RC andφDo decreased with the prolonging of photoperiod.Specially,M_(o),V_(i) and V_(j) of Q.variabilis seedlings were the highest,Ψ_(o) andφE_(o) were the lowest under medium photoperiod.Q.glandulifera and Q.variabilis showed a stronger response to photoperiod than Q.mongolica.The shortening photoperiod would significantly reduce the F_(v)/F_(m) and relative growth rate(RGR)of Q.glandulifera,and the prolonging photoperiod would significantly improve the RGR of Q.glandulifera and Q.variabilis,but the F_(v)/F_(m) and RGR of Q.mongolica showed no significant response to photoperiod changes.At the intra-species level,long photoperiod significantly increased the F_(v)/F_(o) and F_(v)/F_(m) of the Yunnan provenance and the RGR of all the three provenances of Q.variabilis increased with photoperiod.(2)Light quality ratio had no significant effects on RGR,energy allocation parameters and quantum yield parameters among three Quercus species and different provenances of Q.variabilis.(3)The significantly interactive effects between light quality ratio and photoperiod on RGR were observed.Under medium photoperiod,the seedlings showed an obvious shade-avoidance response,namely,the RGR of seedlings with low light quality ratio was the highest,which was significantly higher than that in the normal and high light quality ratio.[Conclusion]The results show that there are intraspecific and interspecific differences in response to photoperiod and light quality ratio.The south provenance of Q.variabilis are more sensitive to photoperiod.Q.glandulifera and Q.variabilis have a stronger response to photoperiod than Q.mongolica.Light quality ratio generally has no significant effects among Quercus L.seedlings.The seedlings show obvious shade-avoidance responses only under specific photoperiod.