Morphological And Histochemical Characteristics Of Roots Of 21 Species Of Arbor In Northeast China

Fine roots are important organs for plants to absorb water and nutrients and maintain normal physiological activities.In the long term organic evolution,during their development tree roots branch into different hierarchies,ie branch orders,in ordering to adapt to the heterogeneous soil environments.Therefore,the identification,configuration and function of fine roots have become the focus of research in botany and ecology.In this study,The roots were dissected according to the branching described by Pregitzer.we investigated root morphology,anatomy and tissue chemistry of the five orders in twenty one topical tree species,Determination of 1-5 order root morphology parameters(diameter,root length,specific root length and tissue density),as well as nutrient characteristics of root order(C content,N content,C:N,lignin content,cellulose content,hemicellulose content).The differences in morphological configuration and nutrient content between different tree species and root order levels were compared,and the variation of these root characteristics with root order in tree species was revealed.The main results are as follows:The diameter,root length,specific root length and tissue density of fine roots between 21 tree species are highly heterogeneous.However,it shows a more consistent pattern of change.In the roots of grades 1-5,the average diameter and root length of the roots of the first grade are the smallest and the root length is the highest.As the root order of the fine roots increases,the average diameter of the roots increases,which is lower than the root length.The variation of root tissue density in 21 tree species generally increased with the increase of root order.There were 15 tree species(71.4%)with the lowest density of grade 1 root tissue,and 10 tree species(47.6%)with the highest density of grade 5 root tissue.Among the 21 tree species,with the increase of fine root order,there was no obvious change in the carbon content of 21 tree species.The nitrogen content of 18 tree species(86%)decreased with the increase of fine root order,and 17 tree species(81%)The carbon to nitrogen ratio increased with the increase of fine root order,and the lignin content generally increased with the increase of fine root order.There were 18 tree species(86%).The roots of grade 3 to 5 increased with the fine root order.However,there is no obvious change in the cellulose content of 21 tree species with the increase of fine root order.The hemicellulose content generally decreases with the increase of fine root order,and 18 tree species(86%)grade 5 root and half fiber The content of the prime is the lowest.In this study,a study of 21 arbor species confirmed that the morphological characteristics,nutrient concentration and fine root physiological function of fine roots are closely linked,which provides a deep understanding of the relationship between fine root structure and physiological and ecological functions,and reveals the mechanism of fine root turnover.It is of great significance.