【作者】 姚瑞玲；

【导师】 方升佐；

【作者基本信息】 南京林业大学 ， 森林培育， 2007， 博士

【摘要】 青钱柳[Cyclocarya paliurus（Batal.）Iljinskaja]是我国特有单种属和国家重点保护的濒危植物，具有极高的开发利用价值。本论文以青钱柳为研究对象，在智能人工气候生长室内采用无土水培法，从细胞、组织、器官水平上探讨了渗透胁迫下供试幼苗的耐盐、抗旱机理。同时，结合形态、生理、生长等指标的测定结果，对供试不同种源幼苗的耐盐抗旱性进行综合评价，从而为今后合理扩大青钱柳人工林的栽培范围提供科学依据。主要结论如下：渗透胁迫下，供试种源幼苗叶肉细胞中ATP酶的活性大小及分布位置的差异较大。正常情况时，供试种源ATP酶活性较小，分布位置差异不大，均多分布于细胞核核膜及核染色质上；胁迫后，供试种源ATP酶活性均有所增加，而ATP酶分布位置因处理及种源而异。渗透胁迫下，供试种源幼苗叶片超微结构均受到不同程度的伤害。主要表现为类囊体片层结构肿胀，叶绿体发生降解，细胞核核膜消失，核染色质发生固缩，并伴随有质壁分离现象。渗透胁迫下，供试幼苗叶肉细胞失水，导致栅栏组织、海棉组织变薄，叶片肉质化程度降低，贮水能力下降。同时，由于叶片失水，引起气孔开度变小，尤其以PEG胁迫下的较为明显。盐胁迫下，供试幼苗根系离子微域分布受到显著影响。在0.3％或0.5％NaCl胁迫下，Na⁺、Cl^-的相对含量增加，K⁺、Ca²⁺、Mg²⁺的相对含量降低。随着盐浓度增加，根系各区Na⁺／X(K⁺、Ca²⁺、Mg²⁺)值总体呈上升趋势，Na⁺在表皮和皮层中富集，而Cl^-在中柱、皮层中均含量较高。盐浓度越高，根际pH值越大，根系由介质中吸收养分的潜力减弱。在耐盐阈值范围内，Na⁺、Cl^-主要集中分布于根茎柄等运输器官中，在叶片中的分布较少，随着盐胁迫程度加重，幼苗离子区隔化能力遭到破坏，叶片中Na⁺、Cl^-含量迅速增加。在离子选择性运输过程中，盐浓度越高，幼苗地上器官离子选择性运输能力越弱。渗透胁迫下，供试幼苗叶片发生水分亏缺，相应叶水势降低，进而引起细胞脱水，细胞膜损伤，质膜相对透性增大，叶绿体结构的完整性遭到破坏，加上水分亏缺引起气孔导度降低，导致叶绿素含量降低、光合速率和蒸腾速率下降。同时，叶片水分亏缺导致幼苗迅速启动渗透调节功能，叶片中的脯氨酸、可溶性糖含量增加。渗透胁迫下，供试幼苗器官热值、能量积累增长量及能量分配总体上以叶片较大、根茎居中、叶柄较小。随着胁迫强度增加，幼苗各器官热值减小，能量积累增长量降低，叶片能量所占比例减少，根系能量所占比例增加，茎柄能量所占比例变化不大。渗透胁迫下，供试幼苗受到伤害，根茎发育受阻，幼苗存活率下降。随着胁迫强度增加，苗高、地径、叶面积及生物量增量均呈现下降趋势，各构件及数量的生长变化主要表现为苗高、单株复叶数、侧根数减少，叶片生物量所占比例减少，根系所占比例增大。用主成分分析法对渗透胁迫下供试不同种源、不同处理幼苗的耐盐、抗旱性进行综合评价，结果表明，盐胁迫下供试3个种源幼苗的耐盐能力大小顺序为：安徽黄山＞云南昆明＞江西九江；PEG胁迫下供试3个种源幼苗的抗旱能力大小则为：云南昆明＞安徽黄山＞江西九江；等渗胁迫及其钙调节下，各钙处理幼苗的耐盐能力差异较小，而抗旱能力差异较大；高温与低盐胁迫交互作用下，供试4个种源幼苗的耐盐抗高温能力大小为：江西赣州＞安徽黄山＞云南昆明＞江西九江。综合本试验结果可得，（1）供试4个种源中以江西九江种源的耐盐抗旱能力较弱，云南昆明种源居中，江西赣州和安徽黄山种源较强；（2）供试幼苗的耐盐阈值为1.0g.L^-1左右；（3）等渗胁迫下，外源钙对PEG胁迫调节作用较盐胁迫的明显，相对而言以0.2％Ca（NO₃）₂的作用效果佳。（4）相同胁迫程度时，高温条件下供试幼苗受到的伤害较适温条件下的重。更多还原

【Abstract】 Cyclocarya paliurus （Batal.） Iljinskaja is native to China and is the sole species in its genus. The species has become a endanger species because of hard propagation. Howerver, its multiple values make the species have a big potential market. Until now no information has been presented on the salt and drought resistance of the species. Therefore, the paper discussed the mechanism of tested seedlings enduring salt and resisting drought under osmotic stress from cell, tissue and organ levels by the way of hydroponics in phytotron. At the same time, by combining with the measured results of morphological, physiological and growing index, the ability of seedlings enduring salt and resisting drought was comprehensively appraised for tested different provenances. Accordingly, a scientific basis for expanding the planting area of Cyclocaryapaliurus （Batal.） Iljinskaja plantation has been provided reasonably. The main conclusions were drawn as follows:The difference ATPase activity in mesophyll cells and its distributing location in tested provenances seedlings under osmotic stress was more evident. Under normal condition, the ATPase activity was lower and its distributing location difference was not significant among tested provenances, which located on nuclear membrane and karyotin. After osmotic stress, the ATPase activity in tested provenances all increased. However, ATPase distributing location varied from treatments and provenances.Leaf ultrastructure suffered from different degree damages in tested provenances seedlings under osmotic stress. The main performances was that thylakoids swelled, chloroplast disassembled, nuclear membrane disappeared, karyotin concreted and condensed. Moreover, the phenomenon of cytoplasm separating from cell wall was observed.Under osmotic stress, water losing of mesophyll cells resulted in palisade tissues and spongy tissues attenuated, leaf carnification degree reduced and the ability of leaf storing water declined. Furthermore, because of leaf losing water, stoma opening degree became small, especially, the variation was more distinct under PEG stress.Effect of salt stress on ion micro-distribution in root tissues Was significant. Under 0.3 percent and 0.5 percent NaCl stress, the relative concent of Na⁺ and Cl^- increased, while that of K⁺,Ca²⁺ and Mg²⁺ decreased. With the increasing of salinity, generally, the ratio of Na+ to X(K⁺, Ca²⁺, Mg²⁺) in root tissues presented ascending trend, and Na⁺ aggregated to root epidermis and cortex, while the relative content of Cl^- in root stele and cortex was greater.The higher salt concentration was, the greater rhizosphere pH was. Therefore, the potential of root absorbing nutrition from medium decreased. Within the range of salt threshold, the distribution of Na⁺ and Cl^- mainly converged in root stem and petiole, but was fewer in leaf. With the increasing of salt concentration, the ability of seedlings compartmentalizing ions was damaged, thus the content of Na⁺ and Cl^- in leaf quickly increased. During the course of ion-selective transporting, the higher the salinity was, the worse the abilities for selective transporting ion of seedlings aboveground organs were.Under osmotic stress, resulting from leaf water losing in tested seedlings, leaf water potential decreased, cells were dehydrated, cell membrane damaged, the relative penetration of membrane augmented, as well as the integrity of chloroplast structure was destroyed. In addition, because of water waning, stomatal conductance descended, and then the content of chlorophyll decreased, photosynthetic rate and transpiration rate reduced. At same time, leaf water-deficient resulted in seedlings osmotic adjusting function being activated, and the content of proline and soluble sugar in leaf increased.Concerning of organs calorie, energy accumulation increment and energy allocation, generally, leaf was higher, rootstock was normal and petiole was lower under osmotic stress. With the increase of stress intensity, the calorie in seedlings organs, the increment of energy accumulation and the proportion of leaf energy accounting for total energy all decreased, while the proportion of root energy accounting for increased. But proportions stem and petiole accounting for energy varied slightly.The tested seedlings were damaged from osmotic stress, e. g. the developing of rootstock was blocked, and seedlings survival percentage descended. With the increase of stress intensity, the increment of height, caliper, leaf area and biomass of the seedlings all decreased. Concerning of the varying about component and quantity growth, in general, it showed that the height, the number of leaves per individual plant, the number of side-roots and the proportion of leaf biomass decreased compared to CK, while the proportion of root biomass increased.By the method of principal component analysis, properties of seedlings enduring salt and resisting drought in tested different provenances under osmotic stress were evaluated, and the results showed that the level of salt tolerance for tested three provenances seedlings was in the order of Huangshan provenance from Anhui＞Kunming provenance from Yunnan＞Jiujiang provenance from Jiangxi, the level of drought resistance for tested three provenances seedlings was in the order of Kunming provenance from Yunnan＞Huangshan provenance from Anhui＞Jiujiang provenance from Jiangxi. Under iso-osmotic stress and calcium regulation, the variation in enduring salt ability of seedlings among different calcium treatments was slighter. However, the variation in resistingdrought ability of seedlings among different calcium treatments was more remarkable. Under the interaction of high temperature and low salinity stress, the order in seedlings enduring salt and resisting high temperature ability for tested four provenances was Ganzhou provenance＞Huangshan provenance＞Kunming provenance＞Jiujiang Provenance.In conclusion, firstly, for tested seedlings of four provenances, the ability of enduring salt and resisting drought was that Jiujiang provenance from Jiangxi was iow, Kunming provenance from Yunnan was middle, and Ganzhou provenance from Jiangxi and Huangshan provenance from Anhui were relatively better. Secondly, the threshold of tested seedlings enduring salt was about 1.0 gram per liter. Thirdly, under iso-osmotic stress, the effect of calcium regulation was more evident under PEG stress than under salt stress, and using 0.2% Ca（NO₃）₂ regulation was more effective. Fourthly, under the same osmotic stress, the interaction with the high temperature would speed the damage and make the damage more serious.更多还原