外生菌对植物光合日变化的通径分析——以樟子松为例

[目的]揭示樟子松光合日变化特征及影响因子之间的作用关系。[方法]通过研究4年树龄的樟子松光合日变化特征,设置接种彩色豆马勃菌[Pisolithus tinctorius(Pers.)CokerCouch](接菌组)和不接菌(对照组)2种处理,采用便携式光合测定仪测定樟子松08∶00—18∶00的净光合速率(Pn)及其参数,研究其光合日变化特征。[结果]对照组和接菌组的Pn日变化绘制的都是"双峰"曲线。对照组的Pn是0.89~6.67μmol/(m~2·s),接菌组的Pn是0.51~10.90μmol/(m~2·s),最小值均出现在18∶00,最大值均出现在09∶00。接菌组Pn的日均值显著大于对照组。影响Pn的环境因子存在共线关系。得到多元逐步线性回归方程,对照组:Pn=-120.96+63.083Cond-0.157Ta+8.06Ls+0.001PAR-0.05Ca+1.644RH(R~2=82.9,F=161 279.83);接菌组:Pn=5 910.823+92.104Cond-11.807Ta+12.622Ls-0.006PAR(R~2=0.92.7,F=2 045.23)。通过通径分析得到对照组环境因子对Pn的通径系数(直接作用)的顺序是CondTaLsPARCaRH,间接通径系数(间接作用)的顺序是RHPARTaCaLsCond;接菌组环境因子对Pn的通径系数大小顺序是CondLsPARTa;间接通径系数顺序是LsPARCondTa。接菌组RH、Ca不是限制因子。[结论]试验结果为不同处理下影响Pn的主导因素研究提供了参考。

Path Analysis of Diurnal Variation of Photosynthesis in Plants with Ectomycorrhial Fungi-For Example Pinus sylvestris var.mongolica Litv.

[Objective] The aim was to reveal the relationship between diurnal variation of photosynthesis in Pinus sylvestris and impact factors.[Method] We used portable Pn instrument to determinate the net photosynthetic rate and its parameters of 4 years old Pinus sylvestris var.mongolica between 08:00 and 18:00,and studied the photosynthetic diurnal variation characteristics of natural group and inoculated with Pisolithus tinctorius group.[Result] The photosynthetic diurnal variation characteristics of the control group and the bacteria group were "bimodal curve".The Pn range of the control group was 0.89-6.67 μmol/(m2 · s),and the range of Pn was 0.51-10.90 μmol/(m2 · s);the minimum value appeared at 18:00,and the maximum value appeared at 09:00.There were collinear relationship of the environmental factors that effected Pn.Multiple linear regression equations for the control group was:Pn =-120.96 + 63.083Cond-0.157Ta + 8.06Ls + 0.001 PAR-0.05 Ca + 1.644RH (R2 =0.992,F =161 279.83),and the inoculated with Pisolithus tinctorius group was:Pn =5 910.823 + 92.104Cond-11.807Ta + 12.622Ls-0.006PAR(R2 =0.997,F =2 045.23).Through path analysis about the impact of environmental factors on net photosynthesis rate could get the order of path coefficient for the control group was Cond ＞ Ta ＞ Ls ＞ PAR ＞ Ca ＞ RH,and the order of indirect path coefficient was RH ＞ PAR ＞ Ta ＞ Ca ＞ Ls ＞ Cond;the order of path coefficient for the inoculated with Pisolithus tinctorius group was Cond ＞ Ls ＞ PAR ＞ Ta,and the order of indirect path coefficient was Ls ＞ PAR ＞ Cond ＞ Ta.The RH and Ca of Pisolithus tinctorius group were not limiting factors.[Conclusion] The results provide reference for study on dominant impact factor of Pn under different treatments.