生物炭对干旱胁迫下咖啡苗生长及非结构性碳水化合物的影响OACSTPCD

The purpose of this study was to clarify the effects of biochar applicationon the growth of coffee seedlings and non-structural carbohydrates(NSC)under drought stress.The normal water treatment was as control(W1:65％～70％soil moisture of the maximum water holding capacity with no biochar applied;W2:65％～70％soil moisture of the maximum water holding capacity with 5％biochar applied to dry soil).The pot experiment of continuous drought and rewatering under different biochar treatments was set up as D2 of 5％of soil dry weight and D1 of no biochar applied under the same drought stress.Four treatments were set up for drought and rewatering,which were continuous drought for 9 days(DL),continuous drought for 13 days(DS),continuous drought for 9 days and rewatering for 3 days(DL+R),and continuous drought for 13 days and rewatering for 3 days(DS+R).The changes of dry mass,NSC component content and quality of each organ(root,stem and leaf)were analyzed.The results showed that after 9 days of continuous drought(DL),compared with normal water treatment(W1),the soluble sugar content,starch content and NSC ratio of coffee seedling leaves in D1 treatment decreased by 22.5％,21.1％and 21.1％,respectively.The soluble sugar content and NSC ratio of roots were significantly in-creased by 8.7％and 62.8％,and the soluble sugar content and NSC ratio of stems were significantly increased by 22.0％and 28.2％,respectively.At 13 days of continuous drought(DS),compared with normal water treatment(W1),the dry mass of roots,stems,leaves and total dry mass of D1 treatment decreased by 30.6％,22.2％,34.8％and 30.8％,respectively;the NSC content and NSC ratio of leaves decreased by 23.7％and 16.4％,re-spectively;and the NSC content and NSC ratio of roots increased by 33.8％and 57.9％,respectively.Meanwhile,compared with the treatment without biochar(D1),the total dry mass of biochar treatment(D2)increased by 16.7％,NSC content in roots and NSC ratio in stems decreased by 18.0％and 24.1％,and NSC content and NSC ratio in leaves increased by 22.8％and 15.0％.After 9 days of continuous drought and 3 days of rewatering(DL+R),biochar treatment(D2)significantly restored the NSC content of each organ,and there was no difference be-tween biochar treatment and normal water treatment(W1);and rewatering 3 days after 13 days of drought(DS+R),coffee seedlings without biochar treatment(D1)did not recover,while biochar treatment(D2)had a signifi-cant recovery effect on coffee seedlings,compared with D1 treatment.The total dry mass of D2 increased by 20.3％,the NSC content of leaves increased by 22.7％,and the NSC content of roots and stems decreased by 11.8％and 15.3％.The findings indicated that the application of biochar to soil was an effective way to enhance the drought resistance of coffee and to slow down the drastic changes of NSC components in coffee.