风沙流对樟子松幼树（苗）的磨蚀危害及其生理生态响应机制

Pinus sylvestnis var. mongolica is one of evergreen tree species which are rarely in desert areas of northern China. It is also one of evergreen tree species with greatest planting areas and good development prospect in the future in the desert areas, China. But Pinus sylvestnis var. mongolica also have a fatal weakness, namely its young tree don't tolerate wind blew and sand cut of drifting sand flux. Survival rate of the young tree is only 10% because drifting sand flux damages when they are planted in bare sand land. Developing research on abrasion damage of drifting sand flux on young trees of Pinus sylvestnis var. mongolica and its response mechanism of physic-ecology, not only having a important sciences significance to explore survival mechanism of Pinus sylvestnis var. mongolica in wind-sand environment, but also providing theoretic guidance to raise survival rate of the young tree. But so far, there are lesser literatures on the related research. This project mainly studies changing pattern of morphological characteristics, anatomic structure, osmotic regulation substances, endogenous hormones, activities of protective enzyme and membrane permeability in the leaves of the young tree of Pinus sylvestnis var. mongolica under the condition of different intensities and continuously blow time and blow partition time of drifting sand flux, and analyze physic-ecological response processes and adaptation mechanism of the young trees under lightly abrasion of drifting sand flux and its damaged processes and causes of death under serious abrasion of drifting sand flux, and determine threshold response properties of its tolerance to drifting sand flux and establish the function relations between abrasion damages and different intensities and continuously blow time and blow partition time of drifting sand flux, which provide scientific basis for improve planting Pattern and raise survival rate of the young trees of Pinus sylvestnis var. mongolica

樟子松是我国北方沙区推广种植面积最大的常绿固沙树种之一，具有良好的发展前景。但其有一个致命弱点，即幼树（苗）不耐风吹沙割，在裸露沙地直接造林因风沙流危害成活率只有10%。本项目通过测定不同风沙流流强度、不同吹袭时间、不同吹袭间隔时间条件下，研究樟子松幼树（苗）茎叶生长特征、形态和解剖结构、有机渗透调节物质含量、内源激素含量、保护酶活性和膜透性的变化规律，分析风沙流对樟子松幼树（苗）茎叶的机械磨蚀危害及其逆境生理生态响应过程，探讨轻度风沙流胁迫下樟子松幼树的形态解剖和生理适应机制，以及重度风沙流磨蚀下其受损过程和死亡成因，确定樟子松幼树（苗）耐受风沙流的临界指征，建立樟子松幼树（苗）磨蚀机械危害与风沙流强度、吹袭时间和吹袭间隔时间的量化关系，其研究结果不仅对于揭示风沙环境中樟子松的受损过程和生存机制具有重要科学意义，还可为改进樟子松栽植方式，提高其栽植成活率提供科学指导。

樟子松是我国北方沙区推广种植范围最广，种植面积最大的常绿树种。但其有一个显著缺点，即苗期不耐风沙，在风沙流活动强烈地区种植时，存活率不足10%。为了解净风和风沙流对其幼苗的危害及其生态适应性和生理响应特征，我们申请了本项目。项目主要研究了不同净风和风沙流吹袭时间和强度下，其幼苗株高、直径、冠幅、叶色、生物量等生物指标，光合蒸腾速率和水分利用效率等光合指标，膜透性、保护酶活性、渗透调节物质含量等生理指标的变化。研究结果表明，1）净风吹袭强度的增加通常不改变樟子松幼苗光合速率的日变化规律，但低风速吹袭可导致其日均光合速率、蒸腾速率、气孔导度降低，高风速吹袭导致其日均光合速率、蒸腾速率、气孔导度、胞间CO2浓度增加。风沙流吹袭强度增加，导致其光合速率、气孔导度和水分利用效率的日变化规律发生明显改变，特别是强风沙流吹袭还导致其日均光合速率和蒸腾速率大幅度降低；2）60 min净风吹袭下，随着风吹强度增加，其丙二醛含量大幅度增加，18 ms-1处理较对照增加47.27%；其膜透性在低风速下大幅度增加，强风吹袭下反而下降；叶片SOD活性波动增加，增加幅度不足6.00%，而POD活性大幅度增加，18 ms-1处理较对照增加40.00%；可溶性糖和脯氨酸含量大幅度增加，18 ms-1处理分别较CK增加26.11%和12.56%。结果说明，净风吹袭下POD保护细胞膜的作用大于SOD，可溶性糖和脯氨酸共同起到了渗透调节作用；3）30 min风沙流吹袭下，随着吹袭强度增加，其丙二醛含量波动变化，各处理间的变化幅度不足5%，但其膜透性大幅度增加，并以12 ms-1处理增加幅度最大（51.39%）；其SOD和POD活性、可溶性糖和脯氨酸含量均波动下降，只有SOD活性在18 ms-1处理大幅度增加。结果说明，其保护酶和渗透调节物质均未起到应有作用，这和干旱和高温胁迫所产生的生理响应有很大不同，其机制有待于进一步研究；4）净风和风沙流吹袭对其叶片含水量影响较小，各处理间的幅度只有0.00%～2.00%。净风和风沙流对其幼苗形态特征和生长节律影响也较小，只有强风沙流频繁吹袭其才表现出高生长减缓，茎粗生长加快，冠层覆盖扩大，显示低矮化。项目实施期间，出版专著1部，发表论文33篇，其中SCI收入4篇，国内核心期刊收录28篇；授权专利3项，其中发明专利1项；培养博士研究生3名；全面超额完成各项任务指标。