不同光照条件下东北红豆杉幼苗叶绿素荧光特性日变化

Diurnal Changes of Chlorophyll Fluorescence Characteristics of Japanese Yew Seedlings under Different Light Conditions

为了解东北红豆杉的光适应特性达到高效培育的目的，以5年生东北红豆杉幼苗为研究对象，研究了3种光照条件下（全光照FL、60％全光照F1和30％全光照F2）幼苗荧光参数的日变化规律。结果显示：7：00—17：00时，FL和F1条件下幼苗的Fo分别升高了23．0％和14．0％，F2略有下降。3组幼苗的Fm和Fv／Fm在降到最低点后都有所回升，FL、F1和F2幼苗的Fm最多下降了38．0％，28．0％和23．0％，Fv／Fm下降了14．0％，6．4％和4．2％。F2幼苗的ФPSⅡ最高，变化趋势与光照强度相近；FL和F1幼苗的ФPSⅡ变化趋势相似，在9：00时达到高点后逐渐下降，至15：00时达最低点，只是FL幼苗的更低。3组幼苗ETR变化的明显差异体现在一天中的高光温时段（11：00-15：00时），F2幼苗的ETR呈现峰值，F1幼苗保持平稳，FL幼苗呈现谷值。F2幼苗的妒最高，变化趋势与光照强度一致；FL和F1条件下幼苗的qP在13：00时和15：00时现谷值。F2幼苗的NPQ全天平缓下降；FL和F1幼苗的NPQ在9：00时和13：00时（15：00时）呈现峰值。综合以上荧光参数变化，F2幼苗全天以光化学反应为主，以热辐射形式耗散掉的光能较少。FL和F1幼苗在高光温时段出现光抑制，此时幼苗通过增加热耗散的方式进行了自我保护，且其光合机构未受到破坏。

In order to know the characteristics of light we selected five-year seedlings to study the diurnal c adaptation of Japanese yew for the efficient cultivation, hanges of chlorophyll fluorescence characteristics under three levels of the light control of full light（FL） , 60% full light（ F1 ） and 30% full light（F2）. From 7：00 am to 17：00, Fo of seedlings under FL and F1 controls increased by 23.0% and 14.0%, respectively, and under F2 control Fo fell slightly. Fm and Fv/Fm of three groups of seedlings fell to the minimum and then rebounded, the Fm values of seedlings under FL, F1 and F2 hght controls decreased at the most by 38.0% , 28.0% and 23.0% , respectively, Fv/Fm of seedlings under FL, F1 and F2 light controls decreased at the most by 14.0%, 6.4% and 4.2%, respectively. The ФPSⅡ of seedlings under F2 control reached the maximum and showed the raising tendency during the day, the tendency of ФPSⅡ under FL and F1 light controls were similarity, the ФPSⅡ value under FL and F1 reached at a higher level at 9：00, then decreased gradually, and at 15：00 got the minimum value, and the qbps~ value of the seedlings under FL control had the more lower level. The significant differences of ETR in three sample groups of seedlings appeared during 11：00- 15：00, the ETR of seedlings under F2 control got the maximum value during the time, and the ETR of seedlings under F1 maintained stable, and the ETR of seedlings under FL reached the minimum value. The qP of higher in value than the those under FL and F1 controls, the tendency under light intensity change; the qP of seedlings under FL and F1 controls got the seedlings under F2 control was F2 was consistent with the daily minimum in 13：00 and 15：00,respectively. The NPQ of seedlings under F2 control decreased during the day slightly, the NPQ under FL and F1 controls reached two times peak values at 9：00 and 13-00 （15.00）. Based on the above variation in fluorescence parameters, the photochemical reactions was the primary way in the optical utilization of the yew seedlings under F2 control during the day, and wasted lesser optical energy in the form of thermal energy radiation. The seedlings under FL and F1 controls appeared the photoinhibition in the high-light-temperature periods, at the time the seedlings improve the protection by increasing thermal dissipation, and the photosynthetic organ were not damaged.