修枝对欧美杨107杨水分生理的影响

以欧美107杨为研究对象,从树干液流、蒸腾速率(Tr)以及叶水势(LWP)等杨树水分生理指标角度,探讨修枝处理对这些生理指标在生长季(6—9月)内的影响及其变化规律,并做相应的分析和讨论。试验地Ⅰ以4年生107杨为样木,试验地Ⅱ以6年生107杨为样木。试验地Ⅰ,Ⅱ均设计3个处理组,每个处理组设有3种处理,即对照处理CK(不修枝)、中度处理P1(修掉树冠高度的1/3)、重度修枝P2(修掉树冠高度的2/3)。研究结果表明:1)发生旱情季节(6—8月),液流通量及液流速率呈现P1>CK>P2的规律;正常月份(9月),液流通量及液流速率呈现出CK>P1>P2的规律;P1的液流通量及速率在旱季或正常月份大小基本相同。这表明同正常月份未修枝CK相比,适当修枝(P1)使杨树树干液流始终保持在一定的较低水平,抗旱能力得到一定程度的提高。2)整个生长季内,蒸腾速率(Tr)和叶水势(LWP)都呈现出CK相似文献   

Coast live oak, Quercus agrifolia, susceptibility and response to goldspotted oak borer, Agrilus auroguttatus, injury in southern California

Oak mortality is often associated with a complex of decline factors. We describe the morphological and physiological responses of coast live oak, Quercus agrifolia Née, in California to an invasive insect, the goldspotted oak borer (GSOB), Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), and evaluate drought as a potential inciting factor. Morphological traits of 356 trees were assessed and physiological traits of 70 of these were monitored intensively over one growing season. Morphological characteristics of tree health included crown thinning and dieback; bole staining resulting from larval feeding; density of GSOB adult exit holes; and holes caused by woodpecker feeding. These characteristics were used to rank GSOB infestation/injury into four classes, and taken together, they explained 87% of the variation in a principal component analysis. Drought stress on various size/age and infestation classes of Q. agrifolia was measured by assessing branchlet pre-dawn and solar noon xylem water potential, leaf cell turgor potential, and water use efficiency over one growing season. Both morphological and physiological traits were highly variable in mature and old growth trees. Early summer plant water status (branchlet xylem water potential and water use efficiency) was similar between uninfested and newly colonized trees, suggesting that GSOB are not pre-selecting drought-stressed Q. agrifolia for oviposition. By late summer, leaf water and cell turgor potentials were lower in infested than in uninfested mature trees, suggesting that GSOB infestation causes drought stress in these trees. Among the tree size/age classes, infested old growth trees exhibited the greatest change in water use efficiency over the growing season, and showed greater morphological injury symptoms of decline than infested mature trees. Morphological attributes of decline in Q. agrifolia associated with GSOB were correlated weakly with increasing physiological drought stress among infestation classes of trees. We propose that the collection of morphological responses of Q. agrifolia to GSOB described here can be used to monitor the future expansion of the GSOB distribution as well as the GSOB-induced decline of Q. agrifolia in California.     

树木边材液流传输研究述评

结合作者的研究工作进展，对当前国内外有关树边材木水分传输机理的研究概况进行了述评，分析了树木水分传输驱动力的构成要素及内聚力学说对树木边材水分传输连续体合理解释，探讨了稳态流模型和非稳态模型在描述树木水分传输方面的效果，介绍了树木组织水容的概念及其在调控树木水分传输过程中的作用和意义，介绍了当前国内外导管空穴化和木质部栓塞研究概况、树木边材导管空穴化的发生机制及检测方法、树木输导组织栓塞对水分传输的影响及栓塞脆弱性评价等。     

三种木本植物伤流液中的游离氨基酸

测定了野茉莉科的白花龙与葡萄科的东南爬山虎、葡萄等三种木本植物伤流液中游离氨基酸的种类及数量,也测定了伤流液中总糖量与还原糖的含量。从测定的数据论述了这段时间前后根系贮存物转化概况。结合这三种植物根中氨基酸生物合成问题作出论述,认为根内的氨基酸生物合成是以天冬氨酸为领头的天冬氨酸族氨基酸为主。     

保卫细胞液泡内pH调节的可逆解聚聚合颗粒物性质初探

为研究保卫细胞液泡(GCV)的pH在气孔保卫细胞渗透调节中的作用及蚕豆(Vicia faba)叶片气孔GCV中的颗粒物的性质,本实验采用激光共聚焦显微术配合pH荧光探针BCECF AM的荧光比值法对ABA诱导的气孔关闭过程进行观测,发现:蚕豆气孔关闭过程中GCV的pH升高约0.5(pH5.3→5.8)。分别用pH5.3和5.8的Mes/Tris缓冲液调控离体开放态GCV的pH,透射电镜(4×104倍)观察负染片说明:pH 5.3对开放态GCV液所含颗粒物的线度及分布密度无实质影响;而pH 5.8的处理使取自开放态GCV液所含颗粒物的线度明显增大、分布密度显著减小;非特异性蛋白酶Proteinase K处理可使GCV中的颗粒物消失。基于GCV内颗粒物的线度、形状及对pH调控和对Proteinase K处理的响应,推测此种颗粒物是蛋白质。     

旱地果园起垄覆膜集雨措施对树体水分利用的影响

针对甘肃陇东黄土高原旱地苹果园季节性干旱问题,以15年生长富2号苹果树为试材,研究果园起垄覆膜、小沟集雨技术措施对土壤水分、主干液流速率、叶片光合速率等的影响。结果表明,在萌芽前晴天,覆黑地膜能显著提高主干液流速率;在果树生长季节,覆黑地膜能降低株间蒸发量,较长时间保持土壤水分,提高水分利用效率和叶片光合能力,同时可以...     

转基因（反义ACS和反义Nr）番茄伤流中植物激素的运输＊

以转反义ACS（ACC合成酶）和反义NR（乙烯受体蛋白）基因番茄和普通番茄（Lycopersicon escclentum Mill．）作为试材，通过ELISA（enzyme-linked immunosorbent assay）方法研究了抑制乙烯合成的外源基因转入番茄后，伤流中植物激素的变化。发现转基因番茄和普通番茄在盛花期和盛果期伤流中各种植物激素的含量变化不显著；而到了成熟期伤流中IAA、GA，和CTKs（细胞分裂素）仍然没有显著变化，但转基因番茄伤流中ABA含量与普通番茄相比却显著减少，说明ABA和乙烯对番茄成熟衰老的控制是共同起作用的，乙烯释放量的改变和信号转导途径的抑制都会影响ABA的伤流运输。     

徐淮平原农田防护林带杨树树干液流研究

 为了揭示农田防护林带对附近农作物产生的胁地机制,为农田防护林带的树种配置和制定克服胁地的措施提供理论依据。用热脉冲技术,采用ICT2000TE树干液流测定系统,研究8年生NL80105杨和11年生I69杨生长盛期树干液流的特点及其与环境因子的关系。结果表明:1)NL80105杨和I69杨的单位面积液流通量,分别为0.244L/(cm2 ·d)和0.172L/(cm2 ·d),I69杨的蒸腾耗水强度较NL80105杨的大;2)NL80105杨和I69杨液流的日进程,均呈低—高—低的变化趋势;3)NL80105杨和I69杨,均存在夜间明显的树干液流上升现象。     

Correlations of stomatal conductance with hydraulic, chemical and environmental variables in five urban tree species

Recent findings suggest that stomatal conductance (g_s) may be as closely linked to plant chemical variables as to hydraulic variables. To test this in an urban field setting, we examined seasonal g_s in relation to a number of plant and environmental variables in five temperate, deciduous tree species. Stomatal conductance was generally more closely correlated with abscisic acid concentrations in xylem sap than with shoot water potential, shoot osmotic potential, pH of xylem sap or environmental variables. Seasonal g_s was mostly poorly correlated with shoot water potential and osmotic potential. Among environmental variables, PPFD accounted for most variability in g_s. We tested a model, developed previously in maize, that describes regulation of g_s by abscisic acid concentration of xylem sap with leaf water status acting to modify stomatal sensitivity to the abscisic acid signal. This model explained somewhat more variation in g_s than abscisic acid concentrations alone. Response surface models, especially those incorporating environmental variables, were most successful at explaining g_s. Our findings with urban trees are consistent with the theory of regulation of g_s by root-sourced abscisic acid.     

基于数值模拟的栓塞修复过程中AE信号分析

为探讨木质部栓塞修复过程监测到大量AE信号现象的原因,基于Rayleigh-Plesset方程建立描述栓塞修复过程中空化泡的运动方程,并用数值模拟方法得到空化泡运动方程的解,对AE信号进行动力学分析。结果表明:当木质部液水势升高时,空化泡会塌缩为半径较小的气泡。但经过一次塌缩并不会使栓塞修复。在压强升高的情况下,气泡会经多次塌缩直到形成稳定的微小气泡,栓塞才会完全修复。在气泡多次塌缩的过程中,气泡半径减小,但是并不是单调减小而是以减幅振动的方式减小,从而形成振源,成为AE信号的来源之一。