【作者】 李晓清；

【导师】 高捍东； 李荣伟；

【作者基本信息】 南京林业大学 ， 森林培育， 2010， 博士

【摘要】 本研究以自然分布于美国和墨西哥的希蒙得木[Simmondsia chinensis(Link) Schneider]为研究对象,对其进行水分胁迫和高温胁迫处理,把细胞膜系统、渗透调节系统、光合系统等联系起来系统研究其幼苗期对水分胁迫和高温胁迫的响应,探讨其抗逆机理,进而探寻提高其耐干热能力的方法,筛选优良种质资源,从而为希蒙得木的生产栽培实践提供理论指导。主要研究结果如下:1、随着水分胁迫时间的延长,希蒙得木地上部分生物量占总生物量的比例呈逐渐降低,地下部分生物量逐渐增加趋势。叶片相对含水量和IAA的含量逐渐减少;游离脯氨酸含量、SOD活性、CAT酶活性、POD活性、MDA含量、可溶性糖含量、可溶性蛋白含量、ABA含量出现不同程度的上升趋势。2、在胁迫初期(7天),Pn略有增加,但随着水分胁迫的进程,Pn开始急骤下降,在第28天后,Pn下降速率降低,在胁迫到49天时,Pn接近于0。气孔导度变化趋势基本上与Pn变化趋势平行。水分利用效率在第14天时均达到最高。综合分析得出7个种源希蒙得木幼苗的抗旱能力由强到弱依次为:Z2>Z1>Z3>Z5>Z6>Z7>Z4。3、希蒙得木经高温胁迫处理后,叶片水分含量下降,膜的通透性增加。POD活性变化规律为在T1处理下,其POD活性显著高于对照。但在胁迫程度加重下(T2处理),不同种源幼苗叶片的POD活性表现出不同的变化趋势。高温胁迫下,MDA含量变化规律不明显,脯氨酸含量显著增加。可溶性蛋白随高温胁迫的加重,其含量变化趋势为先升高后降低。综合分析得出7个种源希蒙得木幼苗抗高温能力由强到弱依次为:Z2>Z1>Z5>Z6>Z3>Z4>Z7。4、T1处理的Pn日变化曲线呈双峰型,表现出光合“午休”现象;T2处理的Pn日变化从8:00到10:00持续下降。不同温度处理最大净光合速率(Pn)差异显著,CK处理的Pn是T2处理的2.26倍,T1处理的Pn是T2处理的1.41倍从全天来看,CK、T1、T2处理的SUE平均为7.06%、5.13%、0.41%。5、微生境造林是解决金沙江干热河谷地区希蒙得木造林的有效途径之一,在旱季灌溉,可以提高植株座果率,种子产量是未灌溉植株的7倍以上。更多还原

【Abstract】 In this research, we tooke Simmondsia chinensis (Link) schneider as the trial materials, which is in natural distribution in the United States and Mexico. We treated seedlings with drought and heat stress, associated its cell membrane system, osmotic adjustment system, photosynthetic system to study the respond to those stress treatments. The adverse stress resisitance mechanisms were discussed. Then we could find ways to improve the tolerance of drought and heat stress, and to select superior germplasm resources. This research will provide theoretical guidance to the cultivation and production of the S. chinensis. Our main research results are as followings:1.With the extension of the time of water stress, the aboveground biomass ratio of total biomass of S. chinensis was decreased,while the underground biomass gradually increased. Besides, the leaf relative water content and IAA levels were reduced; free proline content, SOD activity, CAT activity, POD activity, MDA content, soluble sugar content, soluble protein content, ABA content rised in different degrees.2.During the stress period (7 days),Pn increased slightly,but in the water stress procecess, Pn decreased dramatically.After 28 days,the decreased rate of Pn decreased, and till the 49 days, Pn was close to 0.The Stomatal conductance’s change trend was basically parallel with Pn.And the water utilization efficiency in the 14th days was the highest.The ability of the tolerance to drought stress of the seven kinds of provenanc as follows: Z2>Z1>Z3>Z5>Z6>Z7>Z4.3.The leaf water content decreased and the membrane permeability increased under the heat stress.The POD activity was significantly higher than the control at T1 treatment.However, POD activity of different provenanc seedlings showed different variation trends at T2 treatment.Under the heat stress,MDA content showed unobvious changes and proline content increased significantly.The content of soluble protein increased at first and then decreased with the increament of heat stress degree. The ability of the tolerance to heat stress of the seven kinds of provenanc as follows: Z2>Z1>Z5>Z6>Z3>Z4>Z7.4.The daily change of Pn was bimodal under T1 treatment,the seedling showed "midday depression" phenomenon.The diurnal variation of Pn from 8:00 to 10:00 continually was decreasing when the seedlings treated at T2.Different temperature made the maximum net photosynthetic rate (Pn) obviously different, the Pn iunder the CK treatment is 2.26 times as high as the T2 treatment, the Pn in the T1 treatment is 1.14 times to the T2 treatment,and the average SUE of CK,T1,T2 were 7.06%, 5.13%, 0.41%.5.The micro-habitat afforestation was one of the most efficient ways to solve afforestation of S. chinensis in Jinsha River dry-hot valley areas.During the dry season, the fruit set percentage could be greatly improved by irrigating.The plant seed production was 6 times higher than those unirigated.更多还原