Study On Physiological Characteristics Of Growth,Photosynthesis And Cold Tolerance Of Teak (Tectona Grandis L.f) Clones

19 clones of teak were used as experimental materials,the growth traits of these clones in different locations were analyzed.The gas exchange parameters,chlorophyⅡfluorescence parametersof different teak clones in both nursery and field were measured.Based on the photosynthetic and physiological characteristics of different teak clones,the seasonal variation of photosynthetic characteristicswas analyzed.Meanwhile,the chilling tolerance capability of teak clones was measured and evaluated.By evaluation and selection in the early phase,a batch of fast-growing,chilling-tolerant superior teak clones were screened out.The results were shown as follows.（1）There were significant differences in tree height growth among the 19 teak clones at different growth phaseand planted areas,and the difference of growth between nursery and field was more significant.The coefficient of variation of teak clones was large between planted sites,so genetic variations and the selection breeding space of teak clones was relatively large.Teak clone number growing well in Chaozhou were 6601,7551,FS3,7886and 7544 respectively.The better growing teak clones in Foshan were respectively 7813,7544,7886 and 7114.The teak clones with better growth in Zhanjiang were 7886,7549,7559 and FS3.The teak clones with better growth in Yangjiang were 7024 and 7114 respectively.The teak clones with better growth in Qingyuan were 7544,7559,7551 and 7765.The teak clone with better growth in Zhaoqing was 7544.The teak clone with better growth in Guangzhou nursery were 6601,7703,7114 and 71-7 successively.The 7544 and 6601 from Myanmar showed excellent growth in the four test sites of Chaozhou,Zhanjiang,Qingyuan fields and Guangzhou nursery.（2）The results of gas exchange,chlorophyⅡfluorescence and growth parameters of teak in Qingyuan field and Guangzhou nursery were as follows:Net photosynthetic rate（P_n）,stomatal conductance（G_s）,transpiration rate（Tr）,PSⅡactual photochemical efficiency（ΦPSⅡ）,photochemistry quenching coefficient（q P）,non-photochemical quenching coefficient（NPQ）and water use efficiency（WUE）of teak clones between file and nursery were highly significant difference（p<0.01）,the growth parameters were also highly significant difference among clones.The eigenvalues of net photosynthetic rate（P_n）,water use efficiency（WUE）,PSⅡactual photochemical efficiency（ΦPSⅡ）,quantum efficiency of photosystemⅡcenters（Fv/Fm）,photochemical quenching coefficient（q P）,and seedling height（H）of teak clones in field were significantly higher than that in nursery.But non-photochemical quenching coefficient（NPQ）in nursery was significantly higher than that in the field.The teak clones with good growth in Qingyuan were FS3;the clones with high photosynthetic rate were 71-7and FS3;the clones with high water use efficiency were 7703,7024,7552,and 7813.The clones with good growth in nursery were 7114,7703,6601,71-7;the clones with high photosynthetic rate were 71-7,FS3,7024,7514;the clones with high water use efficiency were71-7,7551,7544,7549.The photosynthesis rate of 71-7 and FS3 from Indian provenances was the highest in nursery and field.The water use efficiency（WUE）,PSⅡactual photochemical efficiency（ΦPSⅡ）,PSⅡmaximum photochemical efficiency（Fv/Fm）,photochemical quenching coefficient（q P）,and seedling height（H）were higher than those of nursery.The non-photochemical quenching coefficient（NPQ）characteristic value of teak clones was higher than that in field.According to the correlation analysis results,there was significant positive correlation between net photosynthetic rate,stomatal conductance and transpiration rate.Net photosynthetic rate（P_n）has significant positive correlation with both PSⅡactual photochemical efficiency（ΦPSⅡ）and PSⅡmaximum photochemical efficiency（Fv/Fm）.Water use efficiency（NPQ）has a significant negative correlation with stomatal conductance（G_s）and transpiration rate（Tr）.（3）There was no significant difference in net photosynthetic rate（P_n）of teak clones within three months.The difference in stomatal conductance（G_s）,intercellular CO₂concentration（C_i）,and transpiration rate（Tr）was highly significant,all tending to increased firstly and then decreased.So,the value of G_s、C_i、Tr in September was significantly bigger than those in July and November.The water use efficiency（WUE）of teak clones was also significantly different during the three months,tending to increased firstly and then decreased,reaching a maximum in November.The PSⅡmaximum photochemical efficiency（Fv/Fm）and the photochemical quenching coefficient（q P）of teak clones were highly significantly different.The non-photochemical quenching coefficient（NPQ）was significantly different,and PSⅡactual photochemical efficiency（ΦPSⅡ）was not significant.The PSⅡmaximum photochemical efficiency（Fv/Fm）showed a trend of rising first and then decreasing.（4）The results of chilling tolerant physiological indexes of different teak clones were as follows:The variance analysis results of 19 teak clones were highly significant when treated at temperature of 3°C.The relative conductivity（REC）and superoxide dismutase（SOD）activity increased with the decrease of air temperature.The content of free proline（Fpro）and non-photochemical quenching coefficient（NPQ）decreased first and then increased.The PSⅡmaximum photochemical efficiency（Fv/Fm）increased first and then decreased.The PSⅡactual photochemical efficiency（ΦPSⅡ）and photochemical quenching coefficient（q P）of most teak clones decreased with temperature.Through comprehensive evaluation of various physiological indicators,the teak clones with strong chilling tolerance were respecitvely FS3,7551,7663 and 7544,which can be used for future promotion and application.FS3 from Indian provenances performed well in all indicators and was initially identified asthe chole of high chilling tolerance.