Response And Adaptability Of Growth,leaf Color And Photosynthetic Characteristics To Heterogeneous Habitats Of Introduced Acer Palmatumn

Acer palmatum is a plant belonging to the Acer in the family Anacardiaceae.It has beautiful tree appearance and unique leaf shape,and is deeply loved by people for its bright and rich leaf color and stable and long-lasting ornamental period.It has made up for the shortcomings of the past garden greening,such as a single color and monotonous form,and has become an important garden ornamental tree species in China.However,Acer palmatum,which introduced from other places,is often used in the construction of beautiful villages in Chongqing,due to the lack of observation and research on the adaptability and ornamental properties of the habitats where it was introduced,most of the introductions ended in failure,bringing significant economic losses to the introducers and enterprises.In this study,this study was based on the introduction of Acer panaceum（HWJ;SJHF,CZM）as the research object,were measured under different habitats（H1,H2,H3,H4）of each Acer panaceum in dynamic growth,plant height,ground diameter and crown,was born,base diameter,branch number branch length,leaf area,leaf length,leaf width,leaf thickness and specific leaf area;leaf photosynthetic characteristics（photosynthetic pigment,chlorophyll fluorescence,the response of light and CO₂ response,gas exchange parameters）;leaf color（L^*,a^*,b^*,R,G,B,H,S,V,C^*,INT,DGCI）and adaptability（high temperature adaptability,low temperature cold hardiness,disease resistance ability）.The relationship between environmental factors and the growth,photosynthetic characteristics,and photosynthetic characteristics of Acer panaceum was discussed.By studying the response of introduced Acer panaceum to different habitats,the key ecological factors affecting the growth,photosynthetic characteristics,and photosynthetic characteristics of Acer panaceum were analyzed,and the species with the best adaptability within the scope of this experiment was identified,with a view to providing theoretical reference for the introduction and domestication,cultivation management,and selection of suitable growth areas of Acer panaceum in Chongqing.The main research results are as follows:（1）The plant height,ground diameter,crown width and leaf traits were significantly affected by different habitats.In this experiment,from May to June,the growth of plant height,ground diameter,and branch length of Acer panaceum were the largest in different habitats;since September,due to the decrease in temperature,the plant height and branch length have no longer increased,but the ground diameter has slightly increased.The annual growth rates of plant height and ground diameter of the SJHF were 40%-48%and 47%-58%;CZM were 34%-39%and 46%-63%;HWJ were 30%-39%and 40%-58%,respectively.The annual variation of plant height of the three species Acer panaceums is H1>H3>H2>H4 in different habitats;the annual variation of ground diameter is H3>H1>H2>H4;In H4,the plant height,ground diameter,and crown diameter of each Acer panaceum were the lowest.In the same habitat,the plant height and ground diameter of SJHF were the largest,followed by CZM and the lower for HWJ.The peak period of leaf growth was from March to May,and the growth of leaf length,leaf width,leaf area,and specific leaf area of Acer panaceum under different habitats were significantly higher than those in other months after that,the growth of leaves gradually slowed down.The statistical analysis results showed that there was a significant correlation between the growth characteristics of Acer panaceum and environmental factors,with plant height significantly or extremely significantly correlated with slope aspect,slope,organic matter,AK,and soil moisture content;the ground diameter was significantly or extremely significantly correlated with altitude,slope aspect,slope gradient,pH,organic matter,AN,AP,and soil moisture content;except for TP,leaf area was significantly correlated with other ecological factors.（2）Different habitats could significantly affect the photosynthetic capacity of each Acer panaceum.The results showed that under the same habitat,the P_nmax、A_nmax、α、R_p、AQY and F_v/F_m of the SJHF were higher than those of the CZM and HWJ.At different altitudes on the same slope direction,there was no significant difference in q _P and NPQ of HWJ among the four habitats,there were no significant differences in q _P,ETR and F_v/F_m of SJHF among the three seasons（P>0.05）;The F_m,F_v/F_m,F_s,NPQ and q _P of CZM were showed H3>H2>H1,and the differences between different habitats were significant（P<0.05）.In the four habitats,there were no significant differences in C_i、L_s and WUE among the three Acer panaceums（P>0.05）;there was no significant difference in CCP,CSP and R_p of SJHF,the sizes of T_r,P_n and G_s of SJHF were H1>H3>H2>H4.At the same slope direction and different altitudes,there was no significant difference in LCP,AQY,R_d of SJHF（P>0.05）;P_nmax of HWJ is H3>H1>H2>H4,and the difference between different habitats was significant（P<0.05）;P_nmax of CZM is H3>H2>H1>H4,and the shady slope was significantly lower than the sunny slope（P>0.05）.（3）This study is based on three species of Acer panaceum under different habitats:Chl a、Chl b、P_nmax、α、R_p、AQY和F_v/F_m,the principal component analysis method was used to reduce the 23 indicators of photosynthetic characteristics of Acer panaceum to 5comprehensive indicators,with a cumulative variance contribution rate of over 91%.Using principal component analysis,a comprehensive scoring equation for the photosynthetic characteristics of Acer panaceum was established,and it was obtained that the photosynthetic characteristics of Acer panaceum under 12 treatments ranked from high to low in order SJHF+H1,SJHF+H2,HWJ+H3,SJHF+H3,CZM+H3,HWJ+H1,HWJ+H2,CZM+H2,SJHF+H4,HWJ+H4,CZM+H1,CZM+H4,from this,it can be seen that the SJHF have good performance in H1,H2,and H3,while the photosynthetic characteristics of each the four species in H4 are poor.（4）Different microhabitats affected leaf pigment content,then affected the transformation and formation of photosynthetic pigments in different growth periods,and finally affected the color effect of leaves.The research results show that during the entire color change period,the red green index a^*and yellow blue index b^*of the leaves of the HWJ are greater than 0 and a^*>b^*,the brightness L^*is higher,the anthocyanin content is higher,and the chlorophyll content is lower,the leaves of the HWJ are generally bright red;For the SJHF and CZM,the a^*representing red and green and the b^*representing yellow and blue are greater than 0 and a^*<b^*,and the brightness L^*is higher,the leaves of the SJHF and CZM generally appear bright yellow.There is a close correlation between the photosynthetic pigments and leaf color parameters of Acer panaceum,except for Car,which has no significant correlation with each leaf color parameter,there is a significant or extremely significant correlation between other photosynthetic pigments and leaf color parameters,indicating that the apparent leaf color of Acer panaceum is the result of the comprehensive action of chlorophyll,carotenoids,and anthocyanins.（5）By evaluating the heat resistance,cold resistance,disease resistance,insect resistance,and overall ecological adaptability of Acer panaceum in different habitats.The study found that different species of Acer panaceum have different sensitivities to environmental factors,the average ecological adaptation index of SJHF in different habitats is between 1.06-1.23,the average ecological adaptation index of HWJ is between 1.1-1.65,and the average ecological adaptation index of CZM is between 1.26-2.31,the adaptability of three varieties of Acer panaceum to the environment can be ranked as follows:SJHF>HWJ>CZM.There is a significant correlation between the average ecological adaptability index of Acer panaceum and environmental factors,with a significant or extremely significant positive correlation with slope and pH,and a significant or extremely significant negative correlation with altitude,SOM,water content,AN,AP,AK,TN,TK.In summary,the growth and photosynthetic characteristics of introduced Acer panaceum are comprehensively affected by environmental factors,while pH,soil moisture content,altitude,and slope orientation play a leading role in the growth and photosynthetic characteristics of Acer panaceum.Among the three introduced Acer panaceum,SJHF has a wide ecological range and strong adaptability to the environment,followed by the HWJ and CZM.During the entire color change period,the leaves of HWJ show bright red,while the leaves of SJHF and CZM show bright yellow.The apparent color of the leaves is the result of the comprehensive action of chlorophyll,carotenoids,and anthocyanins.