【作者】 马书燕；

【导师】 李吉跃；

【作者基本信息】 北京林业大学 ， 森林培育， 2008， 博士

【摘要】 柔枝松是北美地区干旱、瘠薄、石质山地上的先锋树种,良好的防护林树种,经济价值较高,具有开发前景的优良树种。本研究将美国柔枝松不同种源引种至北京、河北和内蒙进行研究,通过对各种源种子活力、苗木适应性和苗木抗旱特性等方面的试验,分析影响柔枝松适应性和抗旱性的主要因子,筛选出适应性和抗逆性较强的种源,为我国干旱半干旱地区选育适应性和抗逆性强的柔枝松种源提供理论依据。研究表明:(1)在固定温度40℃,湿度100%,时间96h的条件下,5个柔枝松种源的各项发芽速率指标均有所下降。种源Rs和Rsd下降明显,发芽率是正常种子的64.1%和62.8%,活力指数是10.3%和38.1%,其中种源Rg和Rsi的值下降较小,表现出一定的抗老化特性,种子活力较强。(2)种子胚乳中内源激素、酶活性和丙二醛(MDA)与活力指数表现出一定的相关关系。在发芽过程中,种源Rsi和Rsd经过老化处理种子中的激素含量、酶活性仍能保持较高水平,膜质过氧化物质丙二醛的含量增加少,表现出较强的抗老化特性。(3)催芽方法:温水(45oC)浸种(1d)—冷水浸泡2d—混河沙(种子:沙子=1:3)—置于室内—常温催芽,能够提高柔枝松种源的发芽率和场圃发芽率,适合柔枝松种源。(4)柔枝松不同种源一年生苗木在鹫峰、萝卜地和东陵的苗高生长节律为:6月底7月开始生长,最快生长期在8月份,在9月底10月初封顶,在内蒙生长期晚近一个月的时间;地径生长节律为:6月中旬开始生长,在9月初以后地径开始迅速生长,10月初出现生长高峰,11月中下旬停止生长。种源Rs、Rg和Rl一年生苗木苗高生长量在东陵最大,分别为8.0cm、7.6cm、6.9cm,种源Rsd在鹫峰苗圃生长量最大,为7.6cm;种源Rs在萝卜地的地径值(0.268cm)最大,种源Rg、Rsd和Rl在东陵地径生长量最大,分别为0.269cm、0.286cm和0.290cm;柔枝松不同种源在东陵的平均主根长度最长,各级侧根条数最多,茎跟比最小,表现出一定的耐旱特性;在4个试验地的越冬保存率均达到70%以上,表现出一定的耐寒特性。(5)柔枝松属于高水势延迟脱水耐旱树种。随着干旱胁迫的增加,种源Rsi和Rsd的苗木水势降低缓慢;种源Rsd各种酶活性的变化比较大,抵抗干旱胁迫的能力较强,种源Rs的酶活性变化比较小,膜受损程度最大;种源Rs、Rg、Rsd和Rl在干旱胁迫的叶绿素a和b含量明显增加;脯氨酸的含量随着干旱胁迫程度的加剧呈持续增加趋势,种源Rg和Rsd增加最多,干旱胁迫后期是正常水分的48.4倍和41.9倍;柔枝松种源Rs根、茎、叶的Δ13C值在白泥井最小,其更加适合在白泥井生长,而最不适宜鹫峰的生长环境;种源Rg、Rsd和Rl的在萝卜地和东陵的值最小,最大值在白泥井。更多还原

【Abstract】 Limber pine (Pinus flexilis James), originated from North America, is kinds of superior plant resources for its ecological, economic and societal values. Introduced provenances of limber pine (Pinus flexilis James) were cultivated in nursery at Beijing、Hebei and Inner Mongolia. Contrast trials about seed vigor, the adaptability and drought adaptation of seedlings were carried out. The provenances suitable to be cultivated in nursery in Northern China were selected. The objective of the study was to provide a theoretical basis for selecting good provenance with high adaptation and strong resistance to adverse environment which adapt to the purpose of afforestation in China’s arid and semi-arid areas. The results show as follows: (1)At a certain temperature 40℃, humidity 100 %, 96 h, the seed germination rate of five provenances by artificial ageing treatment declined. It dropped significantly on Rs and Rsd. Their germination rates were 64.1% and 62.8 % espectively. The activity indexes were 38.1% and 10.3%. The seed germination rate of provenance Rg and Rsi declined smaller, which showed a certain anti-ageing characteristics. Seed vigor stronger.(2)There was a correlation between the endogenous hormone, the activity of malondialdehyde (MDA) and activity index in seed endosperm. In the germination process, the content of hormone, activity of the provenance Rsi and Rsd after the aging can still maintain at a high level, the content of MDA increased less. The provenance Rsi and Rsd showed strong anti-ageing properties.(3)Vernalization: Seeds were immersed in 45℃water bath for 1d, then transfored to cold water for 2 d, finally mixed with sand (seeds: sand = 1:3), and cultured in room temperature. This treatment increased the germination rate and the nursery germination rate of the different kinds of provenance.(4)The height of rhythm of the one-year-old seedlings in Jiufeng, Radish and Dongling: beginning in the end of June and the beginning of July, the fastest growth period in August, stopping grow in the end of September and the early October, growing late a month’s time in Inner Mongolia. Diameter growth rhythm: mid-June growth, in early September began to grow rapidly; the growth peak in early October, stop to grow in November late.The annual growth of seedlings in height in Dongling on Rs、Rg and Rl were the largest, they were 8.0 cm, 7.6 cm and 6.9 cm. Largest, nurseries of Rsd in Jiufeng is 7.6 cm; The diameter value (0.268 cm) of Rs is the largest in Luobodi. However, provenance Rg, Rsd and Rl in Dongling was the largest; they were 0.269 cm, 0.286 cm and 0.290 cm respectively. The average length of the main root of the different kinds of provenance in Dongling were the largest, at all levels, the number of lateral roots was the most, the rate of stems to root was the smallest in Dongling, that shows a certain drought-resistant property. The survival rate through the winter was higher than 70%, That shows a cold-resistant property.(5)The limber pine is a high water potential delay dehydration drought-tolerant species. The water potential of provenances Rsi and Rsd reduced slowly with the drought stress level increase.The activity of CAT, SOD, PPO and APX increased with the process of the drought stress. In particular, the activity of the provenance Rsd changed greatly, the ability to resist drought stress is stronger. Enzymes variation of provenances Rs are relatively small. Chlorophyll a, b and Pro content of Rs, Rg, Rsd and Rl are significantly increased in the process of drought stress. Pro content of Rg and Rsd increased obviously during the severe drought resistance, they are 41.9 times and 48.4 times respectivelt compared with the normal water condition. TheΔ13C value of the roots, stems, leaves of Rs was the smallest in Inner Mongolia. It is more adaptable to grow in Inner Mongolia. TheΔ13C value of Rg, Rsd and Rl was the smallest in Dongling and LuoBoDi, and the value in Inner Mongolia was the biggest.更多还原