黄土丘陵区乔灌木叶水分利用效率及与水力学特性关系

以黄土丘陵区植被演替过程中的7种典型乔灌木(乔木:山杨、油松、辽东栎;灌木:山桃、荆条、黄刺玫和狼牙刺)和人工种植种刺槐为研究对象,研究其叶水分利用效率(WUE)和水力学特性(比导水率Ks、比叶导水率Kl、Huber值HV、导水率损失50%所对应的木质部负压P50、木材密度WD)的变化。结果表明:1)4种灌木的WUE明显高于4种乔木。4种乔木中,以刺槐的WUE为最高,演替早期种山杨的WUE高于演替后期种油松和辽东栎。2)4种乔木的平均Ks明显高于4种灌木,但HV明显低于4种灌木,其Kl与灌木相比差异不大。演替早期种山杨的Ks和Kl明显高于演替后期种油松和辽东栎,但木材密度则小于后两者。山杨的P50高于油松而低于辽东栎和刺槐。人工种植种刺槐具有低Ks和Kl,且对木质部栓塞的抵抗能力弱。3)叶片的长期WUE和水力学特性之间并无显著的相关性,表明演替过程中水分利用效率的变化可能主要受水力学特性以外的其他生理过程的影响。

基于烟叶力学特性的打叶水分适宜性分析及应用

为实现打叶复烤加工过程烟叶保香、企业增效,依据烟叶力学特性等物理特性指标与含水率相关关系,将现行打叶复烤加工标准规定的17%~21%打叶水分调整至16%~18%的适宜打叶水分范围,并在涡阳、楚雄、三明、武夷4家打叶复烤企业进行应用验证。结果表明,二次热风润叶出口含水率下调1.0~1.5百分点,含水率标准偏差控制在0.3%以内;大片率下降,烟片结构分布更趋向于中小片;出片率、成品得率变化控制在1%以内;打叶复烤能源消耗明显下降,最大下降幅度达到22.48%;烤后烟片颜色明显改善,基本扭转了复烤过程烟片颜色变深、变暗的趋势;感官质量明显改变,与应用前烟片感官质量达到差异显著水平。

杀青叶水分及品质与蒸汽杀青机优化组合工艺参数的关系

本文采用正交设计Ｌ８（２７）研究了滚筒连续蒸汽杀青机轴转速、筒转速和筒倾角的优化组合与杀青叶水分及品质的关系。结果表明：轴、筒转速大，杀青叶水分含量低，茶叶品质好。

干旱胁迫对3种灌木生长及叶水分生理的影响

以天目琼花、麻叶绣线菊和小紫珠幼苗为试验材料,采用盆栽控水法设置4个水分梯度,分别为田间最大持水量的95%(对照)、75%(轻度干旱)、55%(中度干旱)和35%(重度干旱),研究干旱对3种灌木生长及叶水分生理的影响。结果表明:随着干旱胁迫的加剧,天目琼花、麻叶绣线菊和小紫珠的株高、单株叶面积显著下降,在重度干旱胁迫下分别降低了27.59%、32.75%、38.37%,22.26%、24.50%、27.84%;总鲜重和总干重分别减少了47.70%、54.44%、65.83%,58.47%、65.81%、63.61%。3种灌木根冠比在轻度干旱胁迫下上升,分别增加了17.57%、7.27%、11.54%;在重度干旱胁迫下下降,分别减少了48.65%、3.64%、7.69%。随着胁迫程度加剧,3种灌木叶片相对含水量和失水率逐渐下降,在重度干旱胁迫下分别减少了6.83%、33.39%、37.32%,7.58%、8.60%、25.13%;水分饱和亏则显著上升,分别增加了31.97%、73.55%、538.58%。总的来说,天目琼花抗旱性最强,麻叶绣线菊次之,小紫珠最不耐旱。

4种柳树苗木叶的PV水分参数对水分胁迫的响应

在温室内研究了瑞典能源柳C号、2号柳、4号柳和陕北红皮柳苗木的抗旱能力。对其盆栽苗木施行水分轻度胁迫、中度胁迫、重度胁迫及正常(供水)生长4种处理,应用压力室和PV技术测定4种柳树苗木在不同处理状态下的叶组织多项水分参数,以此对其苗木的耐旱能力作综合评定。结果表明,在水分胁迫条件下,2号柳苗木叶吸收水分的能力最强;4种柳树的苗木均有一定的渗透调节和保持膨压能力,4号柳、2号柳、红柳的苗木能通过增加叶束缚水的含量来实现渗透调节,但其依靠改变苗木叶束缚水的含量来实现渗透调节的作用有限,红柳、4号柳苗木在土壤相对含水量降至61%时,2号柳苗木在土壤相对含水量降至46%时,其叶由束缚水含量所引起的渗透调节作用消失;在水分胁迫条件下,红柳、4号柳苗木通过改变叶组织细胞壁的弹性来保持其的膨压,2号柳、能源柳C号的苗木主要靠叶渗透调节来维持其的膨压。水分胁迫能增强红柳、能源柳C号、4号柳苗木保持最大膨压的能力,而降低2号柳苗木维持最大膨压的能力;4号柳能通过提高苗木叶细胞原生质忍耐脱水的能力来适应干旱,能源柳C号、红柳苗木叶细胞原生质耐脱水能力对水分胁迫的适应性差,在水分胁迫条件下其耐脱水能力减弱。通过对4种柳树苗木叶组织渗透调节和维持膨压能力的综合比较,其抗旱能力由强至弱依次为能源柳C号、2号柳、红柳和4号柳。

土壤水分对柑橘叶片生长及多胺代谢的影响

本文以2年生宫川温州蜜柑(Citrusunshiu Marc.cv.Miyagawa Wase)盆栽幼树为材料,研究了土壤相对含水量(Soil Water Content,SWC)对橘叶生长和叶片多胺(腐胺Put,亚精胺Spd,精胺Spm)代谢的影响。结果表明:SWC由30%增加到90%,橘叶面积、叶周长、叶宽值均在75%时达最大值12.25cm2、13.84cm、3.19cm,且叶面积、叶周长、叶长、叶宽均与SWC呈显著线性正相关;橘叶Put在SWC=75%时最低(228.95nmol/g,FW),Spd和Spm均随土壤水分递增呈抛物线变化,其最大值分别出现在45%和60%。(Spd+Spm)/Put的比值与叶面积、叶周长、叶长、叶长/宽间呈显著或比较显著负相关,且当SWC≤75%时,此比值(t)与SWC(x)间呈显著正相关(t=0.0112x+0.173,p<0.05)。因此,(Spd+Spm)/Put比值可视为柑橘对土壤水分环境敏感度的指标之一。

沙漠沙化地区柠条直播技术蒸腾速率的水分关系分析

乌兰察布市化德县地处北方农牧交错区,生态环境十分脆弱,属典型的沙漠沙化地区。柠条学名锦鸡儿(caragana korsh inskii kom),是该地区主要的灌木造林树种。文章选择了影响柠条造林成活率的土壤水分,叶水势蒸腾速率等环境因子进行了定期观察。结果表明,柠条具有较强的水分调节能力,当土壤叶片间的水分关系紧张系数低于0.1后,蒸腾速率降低60%以上,以减少水分输出,达到维持生命渡过干旱期的目的,而一旦土壤水分供应充足时,即可迅速生长。

香花油茶不同无性系叶表型性状及叶绿素含量的差异

【目的】为香花油茶良种选育和生态经济型品种筛选提供参考。【方法】以生长良好的30个香花油茶无性系叶为材料,使用叶面积仪和Dualex植物多酚-叶绿素仪对叶表型性状和叶绿素含量进行测定。【结果】叶水分含量特征:叶含水量为52.07%~62.44%,含水量高于55%的无性系占比70%以上。叶表型性状:15号无性系的叶长最大,29号无性系的叶宽、叶面积、叶周长、形状系数均最小;各无性系叶表型性状的变异系数为9.18%~23.07%,叶周长的变异系数最小(为9.18%),叶面积的变异系数最大(为23.07%);叶宽、叶面积与其他叶表型性状间均存在极显著相关性;在主成分分析中,前2个主成分的累计贡献率达到92.708%,说明这2个主成分概括了6个性状的主要信息。其中,叶面积的特征向量值最大,其次是叶宽,叶面积和叶宽是区分香花油茶无性系最主要的叶性状。经聚类分析,香花油茶各无性系可被划分为3个类群。叶绿素含量:香花油茶不同无性系间叶绿素含量存在变异,变异系数为8.48%;25号无性系叶基、叶中的叶绿素含量与其他无性系有显著差异,叶尖叶绿素含量除与18号无性系无显著差异外,与其他无性系均有显著差异。【结论】香花油茶叶表型性状的遗传差异较大;叶中的叶绿素含量与叶总体的叶绿素含量的相关性最高,即叶中部可作为测定叶片叶绿素含量的最佳部位。

玉米抗旱鉴定的形态和生理生化指标研究进展

综合近半个世纪的研究结果表明，玉米抗旱性是玉米在水分胁迫环境下，体内细胞在结构、生理及生物化学上发生一系列适应性改变后，最终在植株形态和产量上的集中表现。因而在干旱条件下，根冠比、植株高度、叶片大小、叶着生姿态，叶片及叶片的蜡、角质层厚度，雄穗大小和ＡＳＩ等形态特征；叶水势、细胞的渗透调节能力，细胞内ＳＯＤ、ＰＯＤ、ＣＡＴ、ＬＯＸ、ＰＥＰｃａｓｅ和硝酸还原酶活性以及Ｖ一Ｃ、ＧＳＨ和Ｐｒｏ的变化，均可作为玉米抗旱性鉴定的指标。

乌龙茶做青生理生化效应及微域环境设备研究进展(一)

乌龙茶做青中温湿度、做青叶水分、呼吸作用及酶等生理生化效应与乌龙茶品质有着密切的关系。建立人工自动化设备控制的微域环境可以使乌龙茶生产达到全天候生产,雨青做好茶,而且在特定环境条件下使做青技术规范化,以便于推广。本文对此进行了综述。

Effects of Water Stress on Leaf Water and Chlorophyll Fluorescence Parameters of Sugarcane Seedling

[Objective] The aim was to explore the effects of water stress on leaf water and chlorophyll fluorescence parameters of sugarcane seedling,as well as to provide basis for the study on sugarcane production and evaluation. [Method] Seven different sugarcane varieties were studied at the seedling stage under drought stress,and the changes of leaf water and chlorophyll fluorescence parameters under stress conditions were detected. [Result] leaf water potential,leaf relative water content and soil relative water content showed a certain amount of internal relationship,the sugarcane varieties that had more tolerant to drought had higher utilization rate of soil water; the correlation analysis and factor analysis suggested that the survival rate at seedling stage under drought stress,Fv/Fm,leaf water potential and relative water content could be used as drought resistance evaluation indicators. [Conclusion] As a relatively independent influencing factor,water potential had dominating effect on drought resistance,and the reliability of Fv/Fm as drought resistance evaluation indicator had been verified.

Response of Ficus microcarpa L.Foliage to Water Stress Determined by Chlorophyll Fluorescence Imaging Technique

[Objective] This study was to determine the response of Ficus microcarpa L. foliage to polyethylene glycol （PEG） simulated water stress using chlorophyll fluo- rescence imaging technique. [Method] The responses of detached leaves from Ficus microcarpa, Ficus benjamina and Nerium oleander to PEG-6000 simulated water stress were detected, and the chlorophyll fluorescence imaging technique was used to detect and analyze the stress at different spots of a single leaf simultaneously. [Result] The responses of Ficus microcarpa, Ficus benjamina and Nerium oleander to dehydration showed that： ~1~） the maximal photochemical efficiency （Fv/Fm） and non- photo-chemical quenching （NPQ） values were small in the reaction center among different detected spots of leaves, and there were great differences between relative electron transport rate （ETR）, photochemical quenching （qP） and quantum efficiency of PSII photochemistry （（φPSII）; （2） the differences of these parameters were more ob- vious among different spots of water-stressed leaves; （3） the discrete degrees of the species with strong resitances decreased significantly. [Conclusion] This study lays the foundation for the further research on the response of plants to drought stress using chlorophyll fluorescence imaging technique.

Leaf Senescence Characteristics and Responses to Water Shortage of Different Hybrid Rice Cultivars during Grain Filling Stage

[Objective] The pattern of leaves senescence was studied to provide reference for the planting technology and breeding rice cultivars resistant to premature senescence. [Method] Six hybrid rice cultivars were cultivated under limited and conventional irrigation managements; after the heading of rice, the root activities, nitrogen content in leaves, chlorophyll content （SPAD value）, net photosynthetic rate and the activities of superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT） were determined. [Result] The rhythms in attenuation of xylem sap flow rate, leaf nitrogen content, chlorophyll content （SPAD value） and net photosynthetic rate of different rice cultivars were significantly different in attenuation starting time, attenuation frequency and attenuation range. Physiological indexes of different cultivars responded inconsistently to water shortage. Extremely significantly positive correlations were found between the decline rates of chlorophyll content and leaf nitrogen content and xylem sap flow rate of roots, the photosynthetic rate and chlorophyll content. The changes in activities of SOD, CAT and POD were different, and responded to water shortage differently in different cultivars. The change dynamic of leaf nitrogen content and chlorophyll content was positively related with the activity dynamic of SOD and CAT. The change dynamic of leaf nitrogen content and chlorophyll content was negatively related with the malondialdehyde （MDA） content. The difference in the attenuation rhythm of physiological indexes of leaves and response to water shortage of different hybrid rice cultivars were related to genotype difference. Increasing roots activities and protecting enzyme activities of leaves benefit to defer attenuation of chlorophyll content and nitrogen content of leaves and to keep stronger photosynthetic function. [Conclusion] The senescence resistance of rice is a combined result of genotype differences and physiological response to environment.

Effects of water stress on Haloxylon ammodendron seedlings in the desert region of Heihe inland river watershed, Gansu Province, China

The water relation and leaf gas exchange of saxoul (Haloxylon Ammodendron Bge, a C4 shrub) seedlings were studied under water stress in 2001. Saxoul seedlings maintained high transpiration when the soil moisture was above 11%. The seedlings were able to take up water from soil with above 6 % soil water content, which was the threshold level of soil moisture for seedlings. The relationship between transpiration and potential evaporation was linear for well-watered seedlings. The de-crease of soil water availability led to different degrees of down-regulation of stomatal conductance, leaf transpiration and net CO2 assimilation rate. The stomata played a relatively small part in determining the net CO2 assimilation rate for the same seedling. The relationship between net CO2 assimilation rate and transpiration was linear diurnally, and reduction scale of leaf transpiration was much bigger than that of net CO2 assimilation rate by waters tress treatments, therefore intrinsic wa-ter-use-efficiency increased. High evaporative demand increased the leaf transpiration but inhibited net CO2 assimilation rate. Because of the effect of VPD on transpiration in this region, the transpiration of well-watered and mild water stress seedlings becomes responsive to change in stomatal conductance over a wider range.

Comparative Study on the Structural and Moisture Characteristics of Leaf from the Plantlets of Three Types of Ornamental Lilium brownii

[ Objective] The study was to compare the structural and moisture characteristics of leaf from the plantlets of three types of omamental lily（ Lilium brownii）. [ Method ] The paraffin sections of leaves of tested lily varieties were prepared and then observed under microscope, and the stomatal characteristics and moisture characteristics of tested lily varieties were measured. I Resaltl All the three ornamental lily varieties show isobilateral leaf, single layer of epicuticula and lower epidermis, and no obvious differentiation of palisade tissue and spongy tissue; their stomata distribute in lower epidermis, and the guard cells are dumbbell-shaped; all of these matedais present high moisture. For the leaf sick- ness, midrib sickness and mesophyll tissue sickness, the order was determined to be oriental lily 〉 Lilium/ongiflorum 〉 Asian lily; of the three types of ornamental lily, Ulium Iongiflorum has the largest stomatai aperture and Asian lily has the smallest; focusing the water potential and moisture, the turn was Asian lily 〉 oriental lily 〉 Lilium Iong＇fflorum. [ Condusion] The study may facilitate the artificial regulation of the growth conditions of the plantlets of ornamental lily.

Photooxidation in Leaves of Facultative CAM Plant Sedum spectabile at C_3 and CAM Mode

The switch from C-3 to CAM pathway was induced by water stress in a C-3/CAM intermediate plant Sedum spectabile Boreau. Typical CAM criteria were observed upon 15 d of withholding water. Leaf delta(13)C value (-%) and water content showed a linear correlation fashion. Chlorophyll fluorescence parameters and antioxidative capacity were altered by water stress. Phi(PSII) and q(P) were reduced by 50% and 34% of the control, respectively, while NPQ rose ca. 180%. SOD activity and ability to scavenge DPPH. free radical went down but membrane permeability changed slightly. However, when an additional photooxidation by MV with high PPFD was carried out with leaf discs from watered (C-3 mode) and drought plants (CAM mode), q(P) and Phi(PSII) in leaves at induced CAM mode stage continuously decreased to a very low level. High 1 - q(P) value (0.86) and 1 - q(P)/NPQ ratio (>1) indicated the presence of high reduction state and unbalance of light energy budget. Together with the marked loss of membrane integral, it was evidenced that photooxidative damage was more serious in the induced CAM mode than in the C-3 mode. No advantage of photooxidation tolerance was found at the induced CAM expression stage of the facultative CAM plant, as compared with its C-3 mode stage, and also with the constitutive CAM plants reported previously. The differences in photooxidation sensitivity between the inducible CAM expressing plant and the constitutive CAM plant were discussed.

Variations in Composition and Water Use Efficiency of Plant Functional Groups Based on Their Water Ecological Groups in the Xilin River Basin

Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hygrophytes. We surveyed the composition, delta(13)C values and proline concentration of PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGs occurred variously in eight steppe communities with different soil moisture status. In wetter habitats, hygromesophytes and hygrophytes were more abundant and accounted for the majority of aboveground biomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) the numerical order of the mean delta(13)C values of PFGs is as follows: xerophytes (-26.38parts per thousand) = mesoxerophytes (-26.51parts per thousand) > xeromesophytes (-27.02parts per thousand) > mesophytes (-27.56parts per thousand) = hygromesophytes and hygrophytes (-27.80parts per thousand); (3) xerophytes maintained relative higher delta(13)C values and water use efficiency (WUE) in habitats of different water availability, whereas delta(13)C values of xeromesophytes were more sensitive to change in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly increased. Significantly positive correlations existed between proline and biomass or delta(13)C values of different water ecological groups.

Response of Chlorophyll Fluorescence Characteristic of Trifolium repens L. to Water Stress

[Objective] The aim was to study response of chlorophyll fluorescence parameters in Trifolium repens L.leaves to water stress from perspective of physiology.[Method] With T.repens cultivar ＂Haifa＂ as tested material,three soil water content levels were set to culture plants,including 75% （no stress,CK）,50% （moderate stress,LD） and 25% （severe stress,HD）,the effects of water stress on chlorophyll fluorescence parameters were determined.[Result] The results showed that the chlorophyll fluorescence parameters changed a little when the relative soil moisture content was 75% and 50%,while the chlorophyll fluorescence parameters such as conversion efficiency of primary light energy （Fv/Fm） of PS Ⅱ,the photochemical quenching coefficient （qP） and the quantum yield of PS Ⅱ electron transport （φPS Ⅱ） decreased respectively when the relative soil moisture content was 25%.[Conclusion] When T.repens in severe drought conditions,the physiological functions were damaged,showing symptoms of drought injury.

Variable chlorophyll fluorescence in response to water plus heat stress treatments in three coniferous tree seedlings

Effects of water and heat stress treatments on chlorophyll fluorescence of Chinese fir (Cunninghamia lanceolata), Masson pine (Pinus massoniana) and western redcedar (Thuja plicata D. Don)_seedlings were monitored during a three-cycle stress period. It was shown that ratio of variable to maximal chlorophyll fluorescence (Fv/Fm) of these three species responded differently to water stress treatments. The Fv/Fm ratio of western redcedar decreased dramatically after water stress, while that of Chinese fir had only a slight reduction and that of Masson pine had no significant change. The experiment also showed that the Fv/Fm ratio of all three species differed significantly under heat stress treatments. Concerning three different water plus heat stress cycles, it was found that the Fv/Fm ratios of Chinese fir and Masson pine measured at the end of each water plus heat stress cycle were not significantly different. However, the Fv/Fm ratio of western redcedar was diminished significantly in response to an increase of stress time. Keywords Chinese fir - Chlorophyll fluorescence - Heat stress - Masson pine - Water stress - Western redcedar CLC number Q945.17 - S791.248 Document code A Biography: Yu Fang-yuan (1965-), male, Ph. Doctor. Associate professor in College of Forest Resources and Environment, Nanjing, Forestry University, Nanjing 210037, P. R. China.Responsible editor: Zhu Hong