Abstract:

In this study, the stoichiometric characteristics in plant organs and the construction of nutrient transmission pathways were studied under changing precipitation patterns to better significance to the survival of native plants. Four treatmentswere tested: Once a month by 20 mm rainfall(W1); twice a month with 10 mm rainfall each time(W2); and 4 times a month with 5 mm rainfall each time(W4) and natural precipitation(CK). We explored thestoichiometric characteristics of leaves, stems and fruitsof S. subcrassa, and also determined differences in its neutral detergent fiber(NDF), acid detergent fiber(ADF)and acid detergent lignin(ADL). The results showed that the N content in the leaves and fruits decreased under each treatments as the plant grew, but increased in stems. Compared with CK, the W4 increased the N contents in the organsduring the growth period; and the P content in the leaves and stems decreased with plant growth, but increased in fruits. The W4 increased the P content in the stems and fruits during the entire period compared to other treatments. Under each treatment, the C:N of the leaves and stems showed a trend of first increasing, then decreasing over time. The C:P and N:P increased, whereas the C:N and C:P in the fruit were stable. The N:P in the fruit decreased. The W4 significantly increased the N:P in the leaves and fruits during the fruit growth period(P˂0.05) compared to the other treatments. Other treatments optimized the nutrient distribution strategy of plant compared to CK. As the plant grew, the NDF, ADFand ADL contents in the leaves and stems increased significantly(P˂0.05); the significant difference was reached in leaves under the same treatment at different stages(P˂0.05). Only W4 increased the ADF content of the stems and fruits during fruit growth. Results indicated that S. subcrassawas more conducive to optimizing nutrient distribution under W4.

Key words: Salsola subcrassa M. Pop., different precipitation frequency, nutrient utilization strategy, ecological stoichiometry