降水格局变化下,研究植物各器官碳(C)、氮(N)、磷(P)化学计量特征和养分传输通路的构建,有助于理解C、N、P元素分配规律,对本土植物的生存和延续具重要意义。本研究设置4个降水处理:每月增水1次20 mm(W1)、每月增水2次,每次10 mm(W2)、每月增水4次,每次5 mm(W4)和自然降水作为对照(CK)。探讨荒漠植物粗枝猪毛菜(Salsola subcrassa M. Pop.)不同器官(叶、茎、果)C、N、P化学计量特征及其中性洗涤纤维(Neutral Detergent Fiber,NDF)、酸性洗涤纤维(Acid Detergent Fiber,ADF)、酸性洗涤木质素(Acid Detergent Lignin,ADL)含量的差异,以期揭示降水模式变化对典型荒漠植物养分获取的影响。结果表明:(1) 各降水频次下,随植株生长,粗枝猪毛菜叶片和果中N含量均逐渐减少,但茎中逐渐增多。与CK相比,W4处理提高了叶片、茎及果在整个生育期内的N含量;叶片和茎中P含量随植物生长均逐渐减少,但果中逐渐增多,与其他处理相比,W4处理提高了茎和果在整个生长时期内P含量。(2) 各降水处理下,叶片和茎中C:N值随时间的推移均呈先增后减趋势,其C:P和N:P值逐渐增大,果中C:N与C:P值较稳定,而果中N:P值逐渐减小。与其他处理比,W4处理显著增大了叶片和果在果实成长期内的N:P值(P˂0.05)。整体上,与CK相比,其余各频次降水均优化了粗枝猪毛菜的养分分配策略。(3) 随植株生长,其叶片和茎的NDF、ADF及ADL含量均显著增加(P˂0.05)且叶片在不同时期同一处理下均达到差异显著(P˂0.05),与其他处理比,仅W4处理增加了茎和果在果实成长期的ADF含量。综上,W4处理下粗枝猪毛菜的养分分配更利于促进植株生长,表明该植物在高频次、小量级降雨下更利于优化养分分配、完成生活史。

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.