Comparative Study On Fine Root Functional Traits Of Chinese Fir From Different Provenances

Cunninghamia lanceolatais the most important fast-growing tree species in south China and plays an important role in China’s forestry production.Chinese fir is widely distributed in 17 provinces and regions of China.Due to the large habitat differences and ecological genetic isolation,different provenances of Chinese fir have formed different morphological and functional traits during their long-term phylogeny,there are different ecological types of Chinese fir.The fine root,which is located at the tip of the root system,is an important organ for absorbing nutrients and water,and is the most sensitive part of the plant to the change of soil environment.Fine root functional traits are important for plant growth,resource uptake and species distribution,and are an important component of plant functional traits,the morphological and functional characters of fine roots of Chinese fir are closely related to water and nutrient uptake and utilization efficiency of Chinese fir.Therefore,the differences of fine root functional traits of Chinese fir from different provenances in long-term adaptation to different environmental conditions were studied,and the differences of morphological characteristics,anatomical structure and chemical composition of fine root were compared,it is of great significance to reveal the mechanism of the formation and evolution of functional traits.In recent years,there have been many studies on the growth and physiological characteristics of Chinese fir from different provenances,but relatively few comparative studies on the root system of Chinese fir from different provenances,especially on the functional properties of fine roots of Chinese fir from different provenances,the formation mechanism of fine root functional traits of Chinese fir has not been revealed.In view of this,based on the detailed analysis of the provenance distribution of Chinese fir in China,this study selected 40-year-old Chinese fir from 16 different provenances in China as the research object,and through the comprehensive field investigation of the growth and soil of Chinese fir from 16 provenances,the complete root sequence root system of Chinese fir from different provenances was excavated and the fine roots of Chinese fir from different provenances were investigated,the differences of morphological structure(mean diameter,tissue density,specific root length,specific surface area),anatomical structure(vascular bundle diameter,cortex thickness,Wigan ratio and cortex ratio)and chemical composition(C,N,p content and C / N,N / p)of the fine roots of Chinese fir from different provenances were compared,based on the correlation analysis of different indexes and environmental factors,the formation of fine root functional shape and its environmental adaptation mechanism of Chinese fir from different provenances were discussed.The main findings are as follows:(1)there were significant differences among provenances(P<0.05)in the average diameter,tissue density,specific root length,specific surface area and other morphological structures of fine roots in each root system of Chinese fir(Cunninghamia Lanceolata).The average diameter and tissue density of the fine roots of Maguan provenances in Yunnan were much larger than those of other provenances,while those of Xinyang provenances in Henan were smaller than those of other provenances.The highest tissue density of the first two classes was from Tianmu Mountain,the lowest from Dechang and Junlian County,the highest from Xinyang,and the lowest from Rongjiang,Guizhou.Specific root length and specific surface area of these provenances decreased with the increase of the rank of root order.The provenances with the largest root ratio of the first two grades were all from Dechang,the smallest from Maguan,the largest from Lechang,and the smallest from You County.(2)there were significant differences in vascular bundle diameter,Wigan ratio,cortex thickness and cortex ratio of fine roots from different provenances(P<0.05).The largest vascular bundle diameter and the ratio of vascular root were from Xinyang provenances in Henan Province and the smallest from Zhenxiong provenances in Yunnan Province.The fine root cortex thickness and cortex ratio of Shangrao provenances were the largest among all provenances,and that of Xinyang provenances was the smallest.(3)the chemical composition indexes of Fine Root C,N,P,C / N,N / P of Chinese fir from different provenances were significantly different(P<0.05).The indexes of C,N,P,C / N of fine roots were significantly different from each other(P<0.05),and they changed regularly with the increase of root order,but the difference of N / P between different fine roots was not significant(P>0.05).Sentence is too long,please supply a shorter sentence.(4)the specific root length of three root sequences of different provenances of Cunninghamia Lanceolata was negatively correlated with annual precipitation,and the specific root length of three root sequences was negatively correlated with soil n elements.The trend of specific surface area is the same as that of Biegen.The largest one is Dechang provenance,the smallest one is Maguan,the largest one is Lechang provenance,and the smallest one is Youxian provenance.There is a significant negative correlation between the specific surface area of each root sequence and the annual precipitation,and there is a significant positive correlation between the average diameter of each root sequence and the elevation of each source.(5)the diameter of Vascular Bundle and the ratio of vascular bundle in fine root of Chinese fir from different provenances were significantly positively correlated with the content of soil N,and the diameter of vascular bundle was significantly positively correlated with soil P,the results showed that the Wigan ratio was positively correlated with soil P,while the cortex thickness and the cortex ratio were negatively correlated with soil N,positively correlated with soil P but not significantly.(6)the fine root C content was positively correlated with the soil n content in different provenances,and the fine root C / N Content was negatively correlated with the soil n content The P content of fine roots in soil was positively correlated with soil p content,while the N / P content of fine roots in the first two grades was negatively correlated with soil P,and that of the third grade was positively correlated with soil P.(7)In summary,the morphological characteristics,anatomical structure and chemical composition of fine roots of Chinese fir from different provenances are significantly different,which is closely related to climatic factors and soil fertility in different provenances.Climatic factors had significant effects on the morphological characteristics of fine roots of Chinese fir of different provenances,while the anatomical structure and chemical composition of fine roots of Chinese fir of different provenances were significantly affected by soil fertility.On the whole,Chinese fir evolved fine roots with larger average diameter with the decrease of provenance area latitude,while the tissue density,specific root length and surface area in the provenance area of Chinese fir with medium belt were all larger than those in the provenance areas of south belt and north belt,and its altitude and climatic conditions were the main influencing factors.The fine root anatomical structure of Chinese fir provenances in the northern zone developed a larger vascular bundle diameter and wigan-ratio,and the middle zone produced the smallest vascular bundle diameter,showing the northern zone >.The south belt & gt;In contrast,the cortical thickness and cortical ratio showed the opposite trend,that is,the median band >The south belt & gt;North zone.In addition,the content of element C in the fine roots of the provenances of the middle provenances was significantly higher than that of the northern and southern provenances,while the content of element N was lower than that of the northern provenances,while the content of element P in the fine roots of the northern provenances was significantly higher than that of the middle and southern provenances.It can be seen that the morphological characteristics,anatomical structure and chemical composition of fine roots of Chinese fir from different provenances change with the change of latitude,which makes the difference of fine roots of Chinese fir from different provenances significant.