氮沉降与干旱胁迫耦合影响油松生长过程和机制

大气氮沉降量增加和干旱胁迫频率增加将影响干旱半干旱地区植物生长过程。目前关于氮沉降与干旱胁迫耦合影响植物光合产物分配、水分运输以及碳水过程的机理尚不清楚，制约着人们对于二者耦合作用影响树木生长机制的认识。本研究以黄土高原广泛种植的油松为研究对象，在田间试验的基础上，采用碳氢双同位素示踪方法，重点研究：（1）氮沉降与干旱胁迫耦合对油松各器官非结构性碳水化合物组分及总量的分配的影响。（2）氮沉降与干旱胁迫耦合对油松各器官渗透调节物质浓度、栓塞程度及水分运输效率的影响。（3）基于碳水协调的非结构性碳水化合物分配变化、渗透调节物质变化及水分运输变化影响油松生长过程和机制。本研究期望在理论上阐明氮沉降与干旱胁迫耦合影响植物生长过程和机制，在实践上为干旱半干旱地区植被恢复提供科学依据和支撑。

The increase of atmospheric nitrogen deposition and the frequency of drought stress will affect the plant growth process in arid and semi-arid areas. The mechanisms of the coupling of nitrogen deposition and drought stress affect the allocation process of plant carbohydrates, water transport, and the carbon-water coupling process are incompletely understood, restricting the understanding of the coupling effect of the two on tree growth mechanisms. The project takes Pinus tabulaeformis, a kind of arbor widely planted on the Loess Plateau, as the research object. Field experiments will be carried out using carbon and hydrogen isotopes combined with tracer methods. The research contents are as follows: (1) The response of plant non-structural carbohydrate components and total amount in each organ to the coupling of nitrogen deposition and drought stress. (2) The effect of coupling nitrogen deposition and drought stress on the osmotic adjustment substance concentration, embolism degree and water transport efficiency. (3) Changing in the distribution of non-structural carbohydrates, in osmotic adjustment substances, and in water transport affect the growth process and mechanism of Chinese pine. This study expects to theoretically elucidate the coupling of nitrogen deposition and drought stress on plant growth processes and mechanisms. In practice, it provides scientific basis and support for vegetation restoration in arid and semi-arid areas.