【作者】 唐全；

【导师】 曹帮华；

【作者基本信息】 山东农业大学 ， 森林培育， 2010， 硕士

【摘要】 本文以23a刺槐(Robinia pseudoacacia)绒毛白蜡(Fraxinus velutina)混交林为研究对象,试验Ⅰ(大田试验)在林分调查的基础上,伐取样木,通过树干解析,研究了混交林和纯林中刺槐、白蜡的生长规律;利用树木圆盘,分析了盐离子在树体不同高度的累积情况,并对年轮生长指数与历年气象因子进行了相关分析;利用全自动微型气象站全天候检测林分气象和土壤生态环境因子的变化过程,利用TDP(Thermal Dissipation Probe)树干径流测定系统连续测定分析了混交林和纯林刺槐、白蜡单株树干边材液流的时空变化规律;在进行液流测定的同时,对混交林和纯林5个层次(0-20、20-40、40-60、60-80、80-100cm)的土壤进行含水量和含盐量的测定;利用光合作用测定系统测定分析了刺槐白蜡混交林及纯林叶片光合能力。试验Ⅱ(盆栽试验)采取刺槐单独栽植、白蜡单独栽植、刺槐白蜡混栽的方式,通过持续加盐进行盐胁迫试验,研究混栽及单独栽植刺槐和白蜡的生长、光合特性、液流特征、渗透调节能力、土壤酶活性、土壤营养对盐胁迫的不同响应。主要研究结论如下:试验I:林分调查结果表明,混交林林相好、林分郁闭度高,对两树种的生长均表现出了一定的促进作用,尤其是对白蜡的生长促进作用更为明显。刺槐纯林枯梢率为51%,混交林中的刺槐枯梢率为43%。树干解析表明,刺槐、白蜡材积生长曲线同非盐碱地条件下树木生长曲线不同,混交刺槐、白蜡材积累积生长量显著大于各自纯林的,材积连年生长量随着林龄虽都在下降,但混交林中刺槐、白蜡的下降幅度要小于各自纯林,表明刺槐白蜡混交林虽然已进入衰退状态,但是比起各自纯林,刺槐白蜡混交林衰退程度较轻。混交林及纯林中刺槐、白蜡树干盐分离子(Na+、Ca2+、Mg2+、K+)空间分布规律不一致,但是从基部到梢部,总体上呈现出“高-低-高”的变化趋势。混交林及纯林中刺槐白蜡树干液流平均速率9月要大于5月。混交林中刺槐树干液流平均速率在5月为纯林的145%,在9月为纯林的109%;混交林中白蜡树干液流平均速率在5月为纯林的209%,在9月为纯林的192%。液流速率制约着蒸腾量,所以混交林刺槐、白蜡比其各自纯林的生命活动更加旺盛。液流速率与外界环境因子成显著相关。液流测定同期的土壤含水量、含盐量测定结果表明,9月份土壤含水量大于5月,混交林0~40cm根系分布层土壤含水量大于刺槐、白蜡纯林,而含盐量则相反,9月低于5月的,这是因为土壤含盐量与含水量具有相关性。混交林表层土壤含盐量(0~40cm)小于刺槐、白蜡纯林。试验II:刺槐白蜡混栽与单独栽植之间抗盐性能力存在差异,具体表现在:盐胁迫明显抑制了刺槐、白蜡苗的生长,但是混栽刺槐、白蜡在盐胁迫下的生长量较大,显示出了刺槐、白蜡混栽对盐胁迫有一定的抗性。随着盐胁迫的加剧,刺槐、白蜡的净光合能力降低,混栽刺槐与单独栽植刺槐相比,净光合能力相差不大,混栽白蜡净光合要高于单独栽植白蜡。盐胁迫降低了刺槐、白蜡的气孔导度,胞间CO2浓度变化不大,混栽和纯栽刺槐Chla、Chlb、Chla+b及Chla/b随盐胁迫程度加深逐渐减小,而混栽和纯栽白蜡Chla、Chlb、Chla+b随盐胁迫强度增加逐渐增大, Chla/b逐渐减小,刺槐、白蜡苗光合能力的变化是上述各个因素共同作用的结果。对照(CK)和低盐处理下,混栽刺槐液流速率峰值变大,但平均液流速率降低,高盐处理下,混栽刺槐液流速率和单独栽植刺槐液流相差不大,但单独栽植刺槐夜间液流速率大于混栽;白蜡与刺槐混栽后,不论是在对照还是盐胁迫下,平均液流速率都变大。在对照和低盐胁迫下,刺槐、白蜡电导率基本没有变化,在高盐胁迫下,刺槐、白蜡电导率急剧升高;刺槐、白蜡叶片MDA含量对盐浓度响应明显,在盐胁迫下,混栽刺槐、白蜡叶片MDA含量远大于单独栽植;刺槐、白蜡叶片Pro含量随盐胁迫程度加深而逐渐增加,但是白蜡叶片Pro含量增加幅度很小;刺槐、白蜡叶片SOD含量的变化表现出了不同趋势,低盐胁迫下,混栽刺槐叶片SOD含量与单独栽植刺槐相差不大,而混栽白蜡叶片SOD含量大于单独栽植白蜡,高盐胁迫下,混栽刺槐、白蜡叶片SOD含量小于各自单独栽植。刺槐白蜡混栽后,根际土壤蛋白酶活性得到了提高;混栽提高了白蜡根际土和非根际土壤脲酶活性,高盐胁迫下,混栽刺槐根际土和非根际土壤脲酶活性高于单独栽植;混栽提高了刺槐和白蜡根际土和非根际土磷酸酶活性;刺槐白蜡根际土过氧化氢酶活性均随着盐胁迫程度的提高而变大,单独栽植刺槐和白蜡非根际土过氧化氢酶活性随盐胁迫程度的提高而变大,混栽非根际土过氧化氢酶活性随盐胁迫程度的提高而逐渐下降。盐胁迫下,混栽对刺槐、白蜡土壤全N含量的影响复杂,表现出不同的变化规律;混栽能显著提高刺槐白蜡根际土和非根际土壤水解氮的含量,随着盐浓度的增高,水解氮含量表现出先上升后下降的趋势;混栽对刺槐、白蜡土壤全P含量的影响比较复杂,在低盐胁迫下,混栽刺槐、白蜡的根际土全P含量大于单独栽植的,在高盐胁迫下,混栽刺槐、白蜡的根际土全P含量小于单独栽植的;混栽能显著提高根际土中速效磷的含量;混栽提高了根际土速效钾的含量,而非根际土中速效钾含量也要高于单独栽植白蜡。更多还原

【Abstract】 The experiment was based on the mixed stands with R.pseudoacacia and F.velutina. Two tests were conducted: one by stands survey, cut down sample trees and stem analysis to study the growth law of mixed and pure stands with R.pseudoacacia and F.velutina; Using trees disk, we analyzed the salt ions in the accumulation of the tree and related analysis of tree-ring index and meteorological factors; Single tree sap flow of pure and mixed stands of R.pseudoacacia and F.velutina and the environmental factor were measured by means of TDP((Thermal Dissipation Probe) and Portable-Meteorological Station; testing the water and salt contents of five soil layers (0-20cm, 20-40cm, 40-60cm, 60-80cm, 80-100cm) in pure and mixed stands; The leaf photosynthesis was tested by photosynthesis system. The other by continual adding NaCl solution to study the growth、photosynthesis、sap flow、osmotic、soil enzyme and soil nutrient of R.pseudoacacia and F.velutina. The main results were as follows:Test I: By the survey of forest growth, mixed stands was better than pure stands in the forest form、canopy density. Mixed stands have promoted the growth of both species, especially the growth of ash more evident; the pure stands of black locust dieback rate of 51%, mixed forest of black locust dieback was lower than pure forest, to 43%.Stem analysis showed that, volume growth curve of locust and ash with the conventional condition tree growth curves of different. Volume growth curves showed that the mixed locust、ash material accumulated volume growth was significantly higher than their respective pure stand. Annual volume increment despite all as the age decreased, but the mixed locust、ash is less than the decline in their pure. Although the mixed stands of R.pseudoacacia and F.velutina into recession, but compared to their pure forest , the decline of the mixed forest to a lesser extent.The salt ions in the locust、ash body of mixed and pure forest displayed spatial distribution inconsistent.The average sap flow of pure and mixed forest in May was greater than September. The average sap flow of locust in mixed forest was 145% of pure forest in May, 109%in September. The average sap flow of ash in mixed forest was 209% of pure forest in May, 192% in September. The sap flow restricted the transpiration, so mixed locust、ash was more vigorous than their respective pure forest.Sap flow rate and environment factors were significantly related. The soil water and salt content showed that: the soil water content in September was larger than in May. Soil water content (0~40cm) of mixed forest was larger than their respective pure forest. Soil salt content in May was higher than in September, this was because the soil salt content and water contend was relevant. Surface soil salt content of mixed forest smaller than the pure of locust、ash forest.Test II: The salt resistant between mixed planted and pure planted were differences. Result as follows:The salt stress significantly limited the growth of black locust and ash, but the mixed planted showed higher growth in salt stress, indicating that the mixed planted had a certain resistance to salt stress.With salt stress increasing, the net photosynthetic capacity of locust、ash declined. The net photosynthesis of mixed planted locust same with the pure, and the mixed ash was higher than the pure. Salt stress reduced the stomata conductance. Chla、Chlb、Chla+b and Chla/b of mixed and pure planted locust with the deepening of salt stress decreased, while the mixed and pure ash increases. The change of photosynthetic capacity of locust、ash is the result of various factors.Control(CK) and low salt treatment, the sap flow peak of locust with mixed planted turn bigger ,but the average flow rate decreases, and the high salt treatment, there is no difference between mixed and pure planted; After the mixed planted ,both in the control or salt stress, the average flow rate of ash was large.The locust and ash unchanged conductivity in control and salt stress, and increased rapidly in high salt stress. Leaf MDA content of locust、ash in response to the salt concentration, under salt stress, leaf MDA content of mixed with locust、ash was much greater than pure plant; Pro content of locust and ash increased with salt stress strengthened gradually increased, but ash leaf Pro content increased only slightly; The content of SOD of locust and ash leaf showed a different trend, and SOD content of the mixed plant with locust little difference with pure planted, but the mixed with ash was more than pure .SOD content of mixed planted leaf was smaller than in pure.Protease activity in rhizosphere soil has been improved after mixed planted under salt stress;Ash mixed planted increased the rhizosphere and non-rhizosphere soil urease activity, and mixed planted locust was higher than pure planted; Increased mixed planted the rhizosphere and non-rhizosphere soil phosphatase activity in the subject remains the same when salt stress; Catalase did not change the law, locust and ash rhizosphere catalase activity were increased with the degree of salt stress while the larger , pure planted locust and ash non-rhizosphere soil catalase activity increased the level of salt stress larger, mixed planted non-rhizosphere soil catalase activity increased with the degree of stress gradually decreased.Under salt stress, it was complex that mixed planted influenced soil total N, showing a different variation;Mixed planted can significantly improve the locust rhizosphere and non-rhizosphere hydrolysable N content, as salt concentration increased, the hydrolysable N content increased and then showed a downward trend; It was complex that mixed planted influenced soil total P, under low salt stress, the rhizosphere soil total P content of mixed planted more than pure planted. under the high salt stress, the rhizosphere soil total P content of mixed planted less than pure planted; The mixed planted can significantly improve the effective P content of rhizosphere soil; Mixed planted increased effective K content of rhizosphere soil, and the effective K content of non-rhizosphere soil is higher than that pure planted with ash.更多还原