不同光照条件下罗甸小米核桃幼苗的生理响应
Physiological Response of Juglans regia f.luodianense Seedlings under Different Light Conditions

为探讨喀斯特地区特有物种――罗甸小米核桃在不同光照条件下生理响应特征，并为其早期苗木培育提供一定的理论和技术支持，以1年生罗甸小米核桃幼苗为研究对象，观察其在不同光照强度下的生理参数的动态变化。设置100%（全光照CK）、80%、50%、20% 4个光照梯度，每隔？？14 d？？测定其苗高、地径、渗透物质、叶绿素、抗氧化系统相关物质等相关指标70 d内的动态变化，待到动态观测周期结束时测定各处理下植株干重。结果表明，随着光照强度的减弱和时间的延长，相应指标均发生了不同程度的改变，总体来看，在50%光照处理下植物生长状况最佳，相应生理指标如Chl含量、POD活性除个别时期外与CK相比均处于较高水平，而MDA含量、Ssug含量、SOD活性各个处理下与CK并无明显差异，Pro含量随着光照的减弱呈现出逐步降低趋势。试验结果表明，在中等光照（50%）条件下，罗甸小米核桃幼苗具有较高Chl含量和部分保护酶活性，使得罗甸小米核桃幼苗能够积累较大的生物量，在其苗木培育前期采取适度遮阴等措施，能够促进苗木的快速生长。
In order to investigate the physiological response characteristics of Juglans regia f.luodianense seedlings,a unique plant species in Karst region,under different light conditions,and to provide some theoretical and technical supports for its early seedling cultivation,the first-year-old J.regia f.luodianense seedlings were taken as the research objects to observe the dynamic changes in physiological parameters under different light intensities.Four light gradients,i.e.,100% (full-light,control),80%,50%,and 20% were set,and the dynamic changes of seedling height,ground diameter,osmotic substance,chlorophyll,antioxidant system related substances and other related indicators within 70 days were measured every 14 days.The dry weight of the plants under each treatment was determined at the end of the dynamic observation period.The results showed that with the decrease of light intensity and the extension of time,the corresponding indexes changed in varying degrees.Overall,the plant growth was the best under 50% light treatment,and the corresponding physiological indicators such as Chl content and POD activity were at a higher level than the control in addition to individual period.The levels of MDA,Ssug and SOD were not significantly different from those of the control in each treatment,while the content of Pro showed a gradual decrease with the decrease of light intensity.The experiment showed that under medium light (50%),the seedlings had higher Chl content and partial protective enzyme activity,which made the seedlings accumulate larger amount of biomass.Adopting measures such as moderate shading in the early stage of seedling cultivation could promote the rapid growth of the seedlings