Short-term responses of root traits and carbon exudation to drought in a Larix gmelinii plantation
Shuang Yin, Chuankuan Wang, Chunhua Lv, Zhenghu Zhou
Abstract
Root exudation, an important input of carbon (C) into soils, affects plant-soil feedbacks and ecosystem response to environmental change. Most of C exudation comes from a pool of non-structural carbohydrates (NSC) in roots. However, little is known about the effect of drought on root NSC and C exudation simultaneously. We investigated the short-term temporal responses (sampling after one (July), two (August), and three months’ (September) treatment, respectively) of root NSC, C exudation, structural, and chemical traits to drought in a Dahurian larch ( Larix gmelinii , the constructive species in Chinese boreal forest) plantation. The results showed that there were significant temporal variations in root NSC and C exudation, and both of them showed a decreased trend from July to September. Drought induced a significant increase in root NSC in July, and a marginal increase in root C exudation across the drought treatment period. Furthermore, correlation analysis showed that root C exudation was positively correlated with root NSC, and they were correlated with traits of root diameter, specific root length, root tissue density, and nitrogen (N) content. Our findings suggest that drought had different effects on root NSC at different plant physiology and growth stages, it is important to consider the temporal dynamics in assessing the response of plants to drought. Besides, some specific root traits could predict the root C exudation although there was multidimensional trait coordination, it is essential to include the root C exudation as a functional trait for root economic space.