A Study Of Physiological And Ecological Characteristics In Sun And Shade Leaves Of Catalpa Bungei Clones

In this paper,Catalpa bungei clones 9-5-8-20?Y-261-2 were experimental material.This paper discuss the basic differences in sun and shade leaves from the three aspects of physiology,ecology,anatomy.The main results were given as below:?1?The light have asignificantly impact on the structural anatomy of Catalpa bungei clones leaves?p<0.05?.The sun leaves was significantly greater than that of shade leaves in thickness,palisade tissue thickness,palisade spongy ratio,leaf compactness and leaf?p<0.01?.Sun leaves was significantly less than that of shade leaves in leaf tissue porosity?p<0.01?.Catalpa bungei clones 9-5-8-20,leaf thickness is 1.26 times that of the sun leaves of shade leaves;the thickness of palisade tissue of sun leaves 113.60±8.34?m is 1.52 times that of the shade leaves 75.14±8.35?m;Catalpa bungei clones Y-261-2,leaf thickness is1.26 times that of the sun leaves of shade leaves,the thickness of palisade tissue of leaf Sun97.10±4.58?m is 1.24 times that of the shade leaves 77.60±16.56?m.?2?There were significant differences in the photosynthetic parameters between the sun leaves and shade leaves?p<0.05?.The values of sun leaves--photosynthetic rate,transpiration rate,stomatal conductance and water use efficiency,were significantly higher than those of shady leaves.The actual parameters of intercropping CO ₂ concentration of shade leaves were significantly larger than those of sun leaves.The photosynthetic rate,stomatal conductance and transpiration rate of the clonal lines 9-5-8-20 and Y021-2 were analyzed as follows:?p<0.05?.The leaf litter size increased with the increase of photosynthetically active radiation,and increased with the increase of photosynthetically active radiation.The effects of the four models on the photosynthetic rate of the leaves of the clonal leaves and the leaves of the clonal leaves were as follows:the right angle hyperbolic correction model>the exponential model>the hyperbolic hyperbolic model>the non-orthogonal hyperbolic model.Among them,only the hyperbolic correction model can fit the situation that the net photosynthetic rate is inhibited with the increase of light intensity.The values of NPQ and ETR in the leaf parameters of the sun leaves were significantly higher than those of the shade leaves,and the values of Yield was significantly smaller than that of the shade leaves.The results show that the ratio of positive pigtail pigment to the absorption of light of sun leaves can be higher than that of the shade leaves,which avoids the destruction of photosynthesis photosystem.At the same time,NPQ and ETR could reflect the changes of photochemical reaction of sun and shade leaves.?3?There was no significant difference in leaf chlorophyll content between sun and shade leaves.The contents of sun leaves were significantly higher than shade leaves in Nmass,Narea,Parea and Karea.The sun leaves of weight per unit area and the N content of the unit area were higher than shade leaves.The P and K contents per unit area of sun leaves were higher than that of the shade leaves.The difference between N in the sun and shade leaves were higher than that in P and K.The content of soluble sugar and starch in sun leaves was significantly higher than that in shade leaves.