The Research On Physiological And Biochemistrical Characteristics Of Loropetalum Chinense Var. Rubrum

Selecting typically six varieties in three categories (Nenyehong, Touguhong, Shuangmianhong) of Loropetalum chinense var. rubrum, according to Professor Hou Boxin'classification system on Loropetalum chinense var.rubrum of three categories,15 types,41 species.Categories of Nenyehong,including'Meihong Yuanyeqing'and'Meihong Jianyeqing'; categories of Touguhong, including'Dongyan Zihong' and'Mizhi Touguhong'; categories of Shuangmianhong, including'Daye Meihong'and 'Dahong Fu'.As materials of the experiment, studying the phenomena its leaves had turned green at high temperature in summer,comparing the changes of photosynthetic physiological characteristics and in photosynthetic pigment in different categories and the same categories different varieties of Loropetalum chinense var.rubrum, the results are as follows:(1) The diurnal variation of photosynthetic rate:On a day, the changing rules of photosynthetic rate and transpiration rate on six varieties of Loropetalum chinense var.rubrum, at first five months, they showed a asymmetric double-peak curve, but its showed a single-peak curve on October, and the day's maximum and minimum values were almost the same time,the high point appeard about 10 AM,about 17 PM appeard the low point; on six months, the changing rules of stomata conductance and inter cellular carbon dioxide concentration showed a single-valley curve and the trend was relatively consistent, at 9 AM,there was the highest value on a day.(2) The photosynthetic physiological characteristics:The comparison of the apparent quantum yield and photosynthetic rate value in three categories of six varieties of Loropetalum chinense var.rubrum were as follows,on categories, Nenyehong>Touguhong>Shuangmianhong, on varieties, 'Meihong Yuanyeqing'>'Meihong Jianyeqing'>'Mizhi Touguhong'> 'Dongyan Zihong'>'Dahong Fu'>'Daye Meihong'; but on the carboxylation efficiency value, the comparison as follows, on category, Nenyehong>Touguhong>Shuangmianhong, on varieties,'Meihong Yuanyeqing'>'Meihong Jianyeqing'>'Dongyan Zihong'>'Mizhi Touguhong' >'Daye Meihong'>'Dahong Fu'. Six varieties of Loropetalum chinense var.rubrum were little difference on light compensation point,but on light saturation point of the difference was very significant, the category of Nenyehong was significantly higher than other categories, and the value of variety of Meihong Yuanyeqing was the highest of six varieties.(3)The changes in photosynthetic pigments:Had carried on the determination of photosynthetic pigments in the leaves of six varieties of Loropetalum chinense var.rubrum and the results as follows:With the increasing of temperature and the serengthening light, the chlorophyll content of three categories of Loropetalum chinense var.rubrum have a certain increase, but the growth range is inconsistent, on the whole,the largest was category of Nenyehong, the smallest was category of Shuangmianhong.The anthocyanin content of category of Shuangmianhong was always higher and the effect of viewing and admiring was better from May to October, then the anthocyanin content of category of Touguhong and Nenyehong decreased rapidly at high temperature glare, especially the leaves of category of Nenyehong, its almost turned into green.(4) The relationship between net photosynthetic rate and photosynthetic pigments:Net photosynthetic rate with chlorophyll of six varieties of Loropetalum chinense var.rubrum were positively correlated; and negative correlation with anthocyanin.