Comparison Of Root Morphology And Leaf Morphology Of Twenty Hardwood Species In Maoershan Natural Secondary Forest

Fine roots and leaves of the plant are vital organs which are important in the acquisition of essential nutrients and influence tree growth and development. The leaf blade is an organ for photosynthesis. The plant tissue (e.g., root and leaf) structure effects its function. Although the relationship between the eco-physiological function of fine roots and leaves is closed, we don't know how to describe the relationship between the morphology and structure of fine roots and leaves. So there is an important significance to understand the relationship between the eco-physiological function of fine roots and leaves by studying their morphology and structure. In this paper, we studied root morphology (e.g., diameter, length, specific root length and root tissue density) across the first five branch orders, leaf morphology (specific leaf area) and the correlation between them of twenty hardwood tree species from secondary forest in Northeastern China. The main results were below:There was a general regulation of the fine root morphology with ascending branch orders in twenty hardwood species in Maoershan secondary forest. Except for Ulmus pumila, Acer ginnala, Alnus sibirica, Alnus mandshurica and Ulmus laciniata, the first order roots at the distal end of a root system in other fifteen hardwood species had smaller diameter, shorter length, and larger SRL in contrast with higher order roots, which diameter and length increased, and SRL decreased, systemically from the first to fifth order roots. Moreover, above five hardwood species showed that the first order roots had larger (or equal) diameter and lower SRL compared to the second order roots. But there was not a general regulation of root tissue density with ascending branch orders.However, accumulated length in the first three order roots was account for 80% in total first five-order roots, suggesting that lower order roots in twenty hardwood species would have the similar physiological functions though their differences in morphology. In the twenty hardwood species of this study, eleven species was ectomycorrhizae (EM)-dominated fine roots and the nine was arbuscular mycorrhizae (AM)-dominated. However, the average diameter, length and SRL of each order roots for AM species were larger than those for EM species, but the average tissue density for AM species was smaller than those for EM species.Across all twenty hardwood species, there was significantly positive correlation between root length and root diameter. SRL was inversely correlated with root diameter, root length and root tissue density. Root tissue density was not correlated with root diameter and root length. SLA was not correlated with diameter, length, SRL and root tissue density of the 1^st order roots.