【作者】 胡晓健；

【导师】 喻方圆；

【作者基本信息】 南京林业大学 ， 森林培育， 2007， 硕士

【摘要】 本文以当年生马尾松幼苗为研究对象,对广东乐昌、湖北远安、湖南汝城、浙江江山、安徽霍山五个种源马尾松苗木同时进行不同程度的周期性干旱胁迫处理,旨在通过对人工模拟干旱胁迫下马尾松幼苗的生长和生理生化特性的研究,特别是具有渗透调节功能的小分子有机化合物的研究,揭示干旱胁迫下马尾松幼苗的渗透调节机理,找出衡量抗旱性强弱的主要指标,为今后采取科学措施,选育高抗旱性马尾松种源及提高幼苗抗旱能力提供理论依据。通过对各项指标的测定和分析,主要研究结果如下:1、干旱胁迫下,各种源马尾松幼苗随着土壤水分的减少,受到伤害愈加严重,其中广东乐昌种源中度胁迫下长势最好,但重度胁迫下该种源针叶变黄植株较多,而其他四个种源生长势较弱,但相互之间在相同干旱胁迫水平上外观无明显差异。2、干旱胁迫下,各种源马尾松幼苗高生长总体出现了减慢,同时各种源间苗木总生物量总体呈下降趋势。综合来看,五种源中受影响较小的为湖北远安,广东乐昌种源;其次为安徽霍山、湖南汝城、浙江江山种源。3、干旱胁迫下,各种源马尾松幼苗的光合作用受到影响,叶绿素初始荧光(Fo)具有增大的现象,最大荧光(Fm)、可变荧光(Fv)、光能转换效率(Fv/Fm)、以及PSII潜在活性(Fv/Fo)均随胁迫程度的加深而趋于下降。Fm、Fv值随胁迫时间延长先降后升,Fv值变幅较小且种源间差异较小,广东乐昌种源Fm、Fv值较其它种源高。在干旱初期,种源间Fv/Fm值变化幅度较大,Fv/Fo值的变幅小,处理后期Fv/Fm和Fv/Fo值变化趋于稳定。总体来看,广东乐昌种源表现出较高的光合效率,其次为浙江江山、湖南汝城、湖北远安种源、安徽霍山种源光合效率最低。4、干旱胁迫下,各种源马尾松苗木根系活力均呈现出明显的下降趋势,各种源根系活力下降从小到大依次为浙江江山,安徽霍山,湖北远安,湖南汝城和广东乐昌种源。5、干旱胁迫下,马尾松苗木针叶内脯氨酸含量变幅较大,随胁迫程度和胁迫时间的增加呈现上升趋势,但是胁迫达到一定程度后就不再积累,甚至出现下降。游离氨基酸总量的积累则是重度干旱普遍高于中度干旱,各种源马尾松针叶内游离氨基酸的变化比较一致,种源间差异不显著。6、干旱胁迫下,在马尾松苗木针叶内发现了甘露糖、葡萄糖、半乳糖和麦芽糖,尤其是甘露糖、葡萄糖都出现了积累,而且重度干旱下积累水平更高,在干旱胁迫后期积累较快,各种源趋势一致。半乳糖在水分胁迫初期变化不稳定且种源间差异不显著,但长期胁迫下有趋于上升的趋势。麦芽糖含量表现下降趋势。总体来看安徽霍山种源上述糖组分总量积累最多,广东乐昌种源次之,湖北远安、浙江江山、湖南汝城三种源积累相对较少。7、在干旱胁迫下,各种源马尾松幼苗针叶内ABA含量在干旱胁迫初期有较敏感的反应,GA3含量变化不一,没有明显一致性规律,但后期含量均有所上升。而IAA和ZR含量表现出降低,IAA含量反应较缓慢,在胁迫较长时间后变化才表现明显。ZR对胁迫反应较敏感,随干旱程度的加剧ZR含量下降。同时ZR/ABA总体表现下降。根据激素平衡调节抗逆理论综合比较后得出:安徽霍山,广东乐昌种源抗旱性较好,湖北远安、浙江江山、湖南汝城三种源抗旱性较弱。8、依据本试验各项抗旱指标的综合分析、主成分分析及隶属函数综合评价得出,各指标间相关性大多不显著,叶绿素荧光、渗透调节物质因子和内源激素因子可作为马尾松苗木抗旱性评价比较好的指标。对各种源马尾松抗旱性综合评价,认为各种源抗旱能力从大到小为:广东乐昌>安徽霍山>湖北远安>浙江江山>湖南汝城。更多还原

【Abstract】 One-year masson pine seedlings, whose seeds were separately from Lechang, Guangdong province, Yuan’an, Hubei province, Rucheng, Hunan province, Jiangshan, Zhejiang province and Huoshan, Anhui province, were subjected to different degrees of water stress in a three-circle drought stress treatment. Through the studies on the characteristics of growth, physiology and biochemistry of masson pine young seedlings under artificial drought stress treatments, especially the studies on the organic substances with low molecular weight, the purposes of this thesis were to reveal the mechanisms of osmotic adjustment in drought stress, choose the main morphological and physiological indexes for determining the ability of drought resistance of masson pine seedlings, and select the drought resistant masson pine provenance. The results of these studies will provide theoretical basis for guiding the selection of drought resistant masson pine provenance and improving the ability of drought resistance of masson pine seedlings. Through the determination and analysis of morphological and physiochemical indexes in the experiments, the main results were shown as followes:1. The young seedlings of all masson pine provenances were injured along with the decrease of soil water content. The seedling growth of the masson pine provenance from Lechang, Guangdong province was best under mild drought stress, but most needles of the same provenance was withered and yellow under severe drought stress. The seedling growth of other four provenances was poor, and there were no significant difference in needle appearance among these four provenances at the same water condition.2. The height growth and total biomass of all seedlings from different provenances decreased under drought stress. The seedlings from Yuan’an, Hubei province and Lechang, Guandong province were less affected by water stress among five provenances, followed by provenances of Huoshan, Anhui province, Rucheng, Hunan province and Jiangshan, Zhejiang province.3. The seedling photosynthesis of all masson pine provenances was affected under water stress. The initial chlorophyll fluorescence (F0) increased. But Fm, Fv, light conversion efficiency (Fm/Fv) and potential activity (Fv/F0) of PSII had a trend of decrease along with the aggravation of drought stress. The value of Fm and Fv decreased first and then increased thereafter. The change of Fv value was little and there were no big differences among different provenances. But the Fm and Fv value of the provenance from Lechang, Guandong province was higher than that of the other four provenances. The variation of Fv/Fm value was big and the variation of Fv/F0 value was small among different provenances at the beginning of drought stress. But the changes of Fv/Fm and Fv/F0 value became stable at the later stage of drought stress. As a whole, the seedling of provenance from Lechang, Guandong province had higher light conversion efficiency, followed by that of Jiangshan, Zhejiang province, Rucheng, Hunan province, Yuan’an, Hubei province and Huoshan, Anhui province.4. The seedling root vigor of all provenances had a significant trend of decrease. And the range of seedling root vigor from weak to strong was Jiangshan, Zhejiang province, Huoshan, Anhui province, Yuan’an, Hubei province, Rucheng, Hunan province and Lechang, Guandong province. 5. The variation of seedling proline content among different provenances was big and the seedling proline content had an increasing trend along with the aggravation and duration of drought stress. But the seedling proline content would not increase after the stress reached a certain level and even decreased at some extent. The accumulation of total content of free amino acids in severe drought stress was much more than that of mild drought stress. And the changes of total content of free amino acids in different provenances were similar. There were no significant differences in the total content of free amino acids among different provenances.6. It was found that there were mannose, glucose, galactose and maltose in the needle of masson pine seedlings under drought stress, especially mannose and glucose were found to be accumulated. Further, more mannose and glucose would be accumulated under severe drought than under mild drought stress. The mannose and glucose were accumulated more rapidly at the later stage of drought stress, and the trend of accumulation of mannose and glucose content was similar among different provenances. Galatose content had no stable trend of changing and there were no significant difference among provenances. But the galatose content had an increasing trend after a relatively long period of drought stress. Maltose content had a decreasing trend under drought stress. In general, the contents of above four sugars accumulated in the seedlings of the provenance from Huoshan, Anhui province were the highest, followed by Lechang provenance, Guandong province. And those of Yuan’an provenance, Hubei province, Jiangshan provenance, Zhejiang province and Rucheng provenance, Hunan province were relatively less.7. The ABA content of masson pine seedlings from all different provenances was sensitive to drought stress at the early stage of stress treatment. And GA3 content had no regular changing pattern at the early stage but it increased at the later stage in all provenances. The content of IAA and ZR in the seedlings of masson pine from different provenance decreased under drought stress. IAA was not sensitive to drought stress and its reaction to drought stress would be obvious after a relatively long period of stress. ZR was sensitive to drought stress and it decreased along with the aggravation of drought stress. ZR/ABA also decreased under drought stress. According to the hypothesis of phytohormone balance adjustment to stress resistance of plants, a conclusion could be reached as follows: The seedlings from Huoshan, Anhui province and Lechang, Guandong province were stronger in drought resistance and seedlings from Yuan’an, Hubei province, Jiangshan, Zhejiang province and Rucheng, Hunan province were weaker in drought resistance.8. Based on the comprehensive analysis of all indexes, principal component analysis and a general evaluation of membership function, following conclusions were reached: the correlations among different indexes were not significant, and chlorophyll fluorescence, the content of osmotic solutes and endogenous hormones were good indexes for appraisal of the drought resistance of Masson pine. According to a comprehensive evaluation of drought resistance for all provenances, it was concluded that the range of drought resistance from strong to weak could be Lechang provenance>Huoshan provenance>Yuan’an provenance>Jiangshan provenance>Rucheng provenance.更多还原