Effects of drought on root architecture and non-structural carbohydrate of Cunninghamia lanceolata

To provide a scientific basis and technical guidance for afforestation and water management for Cunninghamia lanceolata,this study resistance the adaptability strategies of C. lanceolata roots under drought stress and the physiologicalmechanisms of drought resistance. The growth of the above-ground part,root architecture and non-structural carbohydrate contents( TNC) in the roots of one-year-old potted seedlings was compared under different levels of drought stress for different periods,and the relationships between the indexes was analyzed.The results showed that shoot dry weight( SDW),root dry weight( RDW),root length( RL),root surface area( SA),root volume( RV),root tip number( RT),fractal dimension( FD) of C. lanceolata seedlings decreased with increasing drought. R/T gradually increased,and Root topological index( TI) and root diameter( RD) initially increased and then decreased. The Specific root length( SRL) initially decreased and then increased,whereas the average link length( LL),TNC,and sugar starch ratio showed different trends in different periods. The LL increased gradually with the increase of drought stress on d 30 and 60,but on d 90 it decreased initially and then increased.TNC increased initially and then decreased on the d 30 and d 60,but gradually decreased on d 90. The sugar starch ratio increased initially and then decreased with increased of drought stress on the d 30 and 60. On d 90,it increased initially and then decreased. Drought stress significantly affected the root length distribution at different diameters,and changed with increasing stress duration. There was a significant positive correlation between the above-ground part growth and root growth index( RL,SA,RV,RT,RDW),root architecture index( Root branch angle,FD) of C. lanceolata( P