The BEL1-like transcription factor GhBLH5-A05 participates in cotton response to drought stress

Drought stress impairs crop growth and development.BEL1-like family transcription factors may be involved in plant response to drought stress,but little is known of the molecular mechanism by which these proteins regulate plant response and defense to drought stress.Here we show that the BEL1-like transcription factor GhBLH5-A05 functions in cotton(Gossypium hirsutum)response and defense to drought stress.Expression of GhBLH5-A05 in cotton was induced by drought stress.Overexpression of GhBLH5-A05 in both Arabidopsis and cotton increased drought tolerance,whereas silencing GhBLH5-A05 in cotton resulted in elevated sensitivity to drought stress.GhBLH5-A05 binds to cis elements in the promoters of GhRD20-A09 and GhDREB2C-D05 to activate the expression of these genes.GhBLH5-A05 interacted with the KNOX transcription factor GhKNAT6-A03.Co-expression of GhBLH5-A05 and GhKNAT6-A03 increased the transcription of GhRD20-A09 and GhDREB2C-D05.We conclude that GhBLH5-A05 acts as a regulatory factor with GhKNAT6-A03 functioning in cotton response to drought stress by activating the expression of the drought-responsive genes GhRD20-A09 and GhDREB2C-D05.

Response Mechanism of Plants to Drought Stress

Drought stress is an important factor affecting plant growth and development.It will provide a theoretical basis for cultivating new stress-resistant varieties and improving water utilization rate of plants by studying the regulation mechanism of osmotic adjustment and water transportation under drought stress,and understanding the physiological and biochemical characteristics and stress resistance mechanism.

Exogenous Glycine Betaine Reduces Drought Damage by Mediating Osmotic Adjustment and Enhancing Antioxidant Defense in Phoebe hunanensis

Drought stress negatively impacts growth and physiological processes in plants.The foliar application of glycine betaine(GB)is an effective and low-cost approach to improve the drought tolerance of trees.This study examined the effect of exogenously applied GB on the cell membrane permeability,osmotic adjustment,and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress.Two levels(0 and 800 mL)of water irrigation were tested under different applied GB concentrations(0,50,100,and 200 mM).Drought stress decreased the relative water content by 58.5%while increased the electric conductivity,malondialdehyde,proline,soluble proteins,soluble sugars,and antioxidant enzyme activities(superoxide dismutase,catalase,peroxidase)by up to 62.9%,42.4%,87.0%,19.1%,60.5%,68.3%,71.7%,and 83.8%,respectively,on the 25^(th) day.The foliar application of GB,especially at 100 mM,increased the relative water content of P.hunanensis leaves under drought stress.The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products.Under drought stress,the concentrations of proline,soluble proteins,and soluble sugars in the leaves of P.hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged.Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application.Furthermore,the physiological and biochemical indexes of P.hunanensis showed a certain dose effect on exogenous GB concentration.These results suggest that GB helps maintain the drought tolerance of P.hunanensis.

Evaluation of proline, chlorophyll, soluble sugar content and uptake of nutrients in the German chamomile (Matricaria chamomilla L.) under drought stress and organic fertilizer treatments

Objective: To investigate the effect of drought stress and organic fertilizer on German chamomile(Matricaria chamomilla) nutrient uptake, leaf chlorophyll content and osmotic adjustment under field conditions.Methods: This experiment was carried out through a randomized complete block design with a split factorial arrangement of treatments in three replications. The main plots were subjected to the following irrigation treatments: irrigation after 60, 90, 120, 150 and180 mm evaporation from Class A pan. The sub-plots were treated with three vermicompost doses(0, 5 and 10 t/ha).Results: Although drought stress reduced the nutrient percentages in the shoots, application of vermicompost enhanced the nutrient percentages, particularly when the plants were subjected to moderate to severe drought stress conditions. Moreover, the results of this study showed that the interaction between irrigation treatments and vermicompost rates on leaf chlorophyll content was significant. Comparison between the combined treatments indicated that under normal irrigation and moderate drought stress conditions chamomile plants received 5 and 10 t/ha vermicompost showed significantly higher leaf chlorophyll content comparing to the control treatment.Conclusions: Totally, organic fertilization by vermicompost could partly alleviate the effect of drought stress on chamomile by increasing N, P and K uptake and leaf soluble sugar, especially in stressed treatments.

Interactive effects of drought stress and chitosan application on physiological characteristics and essential oil yield of Thymus daenensis Celak

Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.

DROUGHT-INDUCED UNKNOWN PROTEIN 1 positively modulates drought tolerance in cultivated alfalfa(Medicago sativa L.)

Alfalfa is the most widely cultivated perennial legume forage crop worldwide.Drought is one of the major environmental factors influencing alfalfa productivity.However,the molecular mechanisms underlying alfalfa responses to drought stress are still largely unknown.This study identified a drought-inducible gene of unknown function,designated as Medicago sativa DROUGHT-INDUCED UNKNOWN PROTEIN 1(MsDIUP1).MsDIUP1 was localized to the nucleus,chloroplast,and plasma membranes.Overexpression of MsDIUP1 in Arabidopsis resulted in increased tolerance to drought,with higher seed germination,root length,fresh weight,and survival rate than in wild-type(WT)plants.Consistently,analysis of MsDIUP1 over-expression(OE)alfalfa plants revealed that MsDIUP1 also increased tolerance to drought stress,accompanied by physiological changes including reduced malondialdehyde(MDA)content and increased osmoprotectants accumulation(free proline and soluble sugar),relative to the WT.In contrast,disruption of MsDIUP1 expression by RNA interference(RNAi)in alfalfa resulted in a droughthypersensitive phenotype,with a lower chlorophyll content,higher MDA content,and less osmoprotectants accumulation than that of the WT.Transcript profiling of alfalfa WT,OE,and RNAi plants during drought stress showed differential responses for genes involved in stress signaling,antioxidant defense,and osmotic adjustment.Taken together,these results reveal a positive role for MsDIUP1 in regulating drought tolerance.

Effect of Water Stress on the Growth and Yield of Cotton Crop (<i>Gossypium hirsutum</i>L.)

Cotton is one of the most important fibre crops playing a key role in economic and social affairs of the world. Water is a critical factor which influences on growth and yield of the cotton crop. Scarcity of water has put tremendous pressure on scientists to introduce drought tolerant cotton varieties. This study was aimed to determine water stress effects on the growth and yield of cotton. The present study was carried out to examine the effect of number of irrigations on the growth and yield of cotton during 2014. The field trial was conducted at the Experimental Fields of Agronomy Section, Agriculture Research Institute, Tandojam, Pakistan. A three replicated Randomized Complete Block Design (RCBD) was employed to layout the experiment having plot size of 2.5 m × 5 m (12.5 m2). Four cotton varieties i.e. NIAB-78, Shahbaz-95, Sindh-1 and TH-224/87 were chosen for this study based on their frequent farmer usage. All the agronomic practices were performed according to standard procedures. Results showed that all the growth and yield components of cotton were significantly (P 0.05) affected by irrigation frequencies. The cotton crop irrigated six times at 21 days interval showed better results with 138.16 cm plant height, 1.45 monopodial branches per plant, 21.83 sympodial branches per plant, 44.58 bolls per plant, 33.86% G.O.T., and 26.97 mm staple length, 149.84 g seed cotton yield per plant and 2271.16 kg·ha-1 seed cotton yield. This study concluded that variety NIAB-78 showed superiority over Shahbaz-95, Sindh-1 and TH-224/87 in almost all the characters of economic importance, and the cotton crop received 6 irrigations at 21 days interval resulted in significantly economical overall performance as compared with 5 irrigations or 4 irrigations with higher seed cotton yield.

外源甜菜碱对烤烟幼苗干旱胁迫的缓解效应

为明确甜菜碱缓解烤烟干旱胁迫的作用机理,以秦烟96为供试品种,用15%的聚乙二醇(PEG 6000)模拟干旱胁迫环境,探究叶面喷施不同浓度(35、40、45、50 mmol/L)的甜菜碱对烤烟幼苗农艺性状及相关生理指标的影响,同时以正常条件下生长的烟苗为正面对照(CK),以干旱胁迫下生长的烟苗为负面对照(CK0),共设6个处理。结果表明,干旱胁迫显著抑制了烤烟幼苗的生长发育,而叶面喷施甜菜碱可以缓解干旱对烤烟幼苗胁迫,其中,45 mmol/L的甜菜碱处理缓解效果最佳,该处理下烤烟幼苗的株高、叶面积、地上部干质量分别较CK0显著增加了6.69%、38.78%和25.00%;超氧阴离子产生速率和MDA含量分别较CK0显著降低了39.88%和52.28%;SOD、POD和CAT活性分别分别较CK0显著增加了44.04%、36.33%和104.26%;叶绿素含量、Pn、Gs和Tr分别较CK0显著增加了177.38%、116.85%、72.97%、67.27%,而Ci较CK0显著降低了22.31%;脯氨酸和可溶性蛋白含量分别较CK0显著提高了156.64%和93.58%;根系活力较CK0显著增加了130.77%;失水率较CK0显著降低了27.27%,而相对含水率较CK0显著提高了12.35%。整体来看,喷施适宜浓度的外源甜菜碱可以显著缓解干旱胁迫对烤烟幼苗的伤害。

盐、干旱胁迫对沙蒿种子萌发与幼苗生理特性的影响

【目的】探明盐、干旱胁迫对沙蒿(Artemisia desertorum)种子萌发与幼苗生理生化特性的影响,找到沙蒿对盐、干旱胁迫的耐受阈值,以利于逆境条件下保障种子萌发和幼苗的生长。【方法】以沙蒿种子为材料,在25℃下对其进行不同浓度NaCl(50、100、150、200和300 mmol/L)和PEG⁃6000溶液(5、10、15、20和25%)胁迫处理,测定种子萌发率、幼苗生物量、渗透调节物质含量以及抗氧化酶活性。【结果】低浓度NaCl(<50 mmol/L)和PEG⁃6000(<15%)对种子萌发和幼苗生长(根长、株高和鲜重)抑制不显著或具有一定的促进效果,而高浓度(>50 mmol/L和>15%)则具有显著的抑制作用。防御响应的渗透调节物质(可溶性糖、蛋白质和脯氨酸)含量和活性氧清除酶(SOD、POD、CAT和APX)活性在低浓度胁迫范围内逐渐增加,在极端胁迫浓度范围内显著下降;膜脂过氧化最终产物丙二醛的含量持续增加。【结论】沙蒿种子萌发与幼苗形态建成对NaCl和PEG⁃6000胁迫的耐受阈值分别小于50 mmol/L和15%。

棉花抗逆性鉴定技术标准体系的建立

棉花是中国主要的经济作物,分布区域广,生产周期长,受生态逆境胁迫影响大。培育和筛选抗逆性强的棉花品种是减少逆境灾害的主要途径,而研究棉花品种的抗逆性鉴定技术和标准是至关重要的基础工作。归纳了近年来国内外作物抗逆性鉴定的基本方法,分析了棉花干旱、渍涝、盐碱、高温热害和低温冻害冷害等5种常发易发非生物逆境(生态逆境)抗逆性鉴定的鉴定时期、鉴定方法、鉴定指标和抗逆性判定级别等,总结了抗逆性鉴定标准制定和标准体系建立的基本原则、框架和内容等。提出了进一步研究的基本思路,主要包括:研究基于光谱/高光谱等新技术的快速便捷无损抗逆性鉴定、复合逆境下抗逆性鉴定、利用分子生物学手段直接找出相关抗逆基因并以此来进行抗逆性鉴定等技术。

两种石斛对干旱胁迫及复水的生理响应

目的:探究金钗石斛和铁皮石斛对水分亏缺环境的适应能力和机制,为其仿生栽培提供理论支持。方法:通过盆栽控水进行持续干旱胁迫和复水处理,研究两种石斛叶片渗透调节物质含量和抗氧化酶活性的变化规律。结果:随着持续干旱时间的延长,金钗石斛叶片可溶性糖含量、可溶性蛋白含量和丙二醛(MDA)含量均呈先升高后降低的趋势,脯氨酸含量、超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性呈持续上升的趋势,而过氧化氢酶(CAT)活性呈逐渐降低的趋势;铁皮石斛叶片可溶性糖含量、可溶性蛋白含量、MDA含量、POD活性呈先升高后降低的趋势,SOD活性和CAT活性呈持续上升的趋势,而脯氨酸含量在干旱初期小幅下降后也呈持续升高的趋势。复水后,到复水20 d时,金钗石斛叶片可溶性糖含量、可溶性蛋白含量、CAT活性均已恢复并降低到充分供水时以下水平,而脯氨酸含量、MDA含量、SOD活性和POD活性仍略高于充分供水时;铁皮石斛叶片可溶性蛋白含量、MDA含量和CAT活性均已恢复并降低到充分供水时以下水平,而可溶性糖含量、脯氨酸含量、SOD活性和POD活性仍略高于充分供水时。结论:两种石斛均具有较强的干旱耐受能力和干旱胁迫后恢复能力。

不同棉花品种种子萌发期耐旱性综合评价

本试验选用45个黄淮棉区不同时期的代表性棉花品种为材料,采用15%PEG-6000溶液模拟干旱胁迫,测定各品种的种子发芽势、发芽率、发芽指数和单株干重、幼苗长度,计算5个萌发指标的相对值,分析各品种萌发指标的差异,并利用模糊隶属函数、相关分析等方法对45个棉花品种萌发期的耐旱性进行综合评价,为萌发期抗旱种质筛选及抗旱棉花新品种选育提供理论依据。结果表明,干旱胁迫抑制45个棉花品种萌发,品种间存在显著差异;相关分析显示,耐旱评价值与5个鉴定指标均呈正相关关系,与相对发芽势、相对发芽率、相对发芽指数呈极显著正相关;依据耐旱评价值将45个棉花品种分为高抗旱、抗旱、耐旱、不耐旱4个等级,其中高抗旱品种1个、抗旱品种7个、耐旱品种30个、不耐旱品种7个。说明过去或当前主栽棉花品种萌发期高抗旱及抗旱品种较少,为应对当前旱情加剧趋势,今后棉花育种需加强对萌发期抗旱品种的筛选。

干旱胁迫对桔梗光合作用和生理特性的影响

为了探究干旱胁迫对桔梗光合作用和生理特性的影响,以2年生桔梗为试验材料,设置4个土壤水分处理,分别为土壤相对含水量的80%(对照)、60%(轻度干旱)、40%(中度干旱)、20%(重度干旱),研究不同程度干旱胁迫下桔梗的光合和生理特性。结果表明,随着干旱程度的增加,桔梗叶片净光合速率、气孔导度、胞间CO_(2)浓度、光饱和点、表观量子效率和暗呼吸速率均呈逐渐下降趋势,而光补偿点逐渐升高。当土壤相对含水量为20%时,光补偿点最高,为74.45µmol/(m2·s),比对照上升了67.76%。叶片光合色素含量先升高后下降,土壤相对含水量60%处理下叶绿素a、叶绿素b和类胡萝卜素含量最高,分别较对照增加了18.71%、28.48%、12.25%。桔梗丙二醛、脯氨酸、可溶性糖、可溶性蛋白含量均随干旱程度的增加而增加。过氧化氢酶活性先升后降,土壤相对含水量为40%时活性最强,较对照提高了21.01%。综上,桔梗对轻度和中度干旱表现出一定的适应性,渗透调节物质积累和抗氧化酶活性增加是桔梗耐旱性的关键生理响应过程,但重度干旱胁迫下桔梗膜脂过氧化程度加剧,光合生产力显著下降,最终导致桔梗生长受到严重抑制。桔梗种植管理时,土壤相对含水量不宜长时间低于40%。

干旱胁迫下沙棘叶片细胞膜透性与渗透调节物质研究

研究了干旱胁迫下沙棘幼林苗木渗透调节能力与沙棘耐旱性的关系。结果表明:长期轻度及中度干旱胁迫下渗透调节物质中可溶性糖、游离氨基酸、Pro在干旱中、后期累积显著增加而降低渗透势,使沙棘具备较强的渗透调节能力而表现为低水势耐旱特性;K+在干旱下无显著累积。渗透调节物质(可溶性糖、游离氨基酸、Pro)的共同作用,使长期轻度、中度干旱下沙棘叶片可溶性蛋白降解少,细胞膜透性和MDA含量增加缓慢,重度干旱下也能在一定时间内保持稳定,这些物质是构成沙棘强耐旱性的内在基础。

玉米叶片光合作用和渗透调节对干旱胁迫的响应

以2个不同抗旱性玉米品种郑单958(抗旱性强)和陕单902(抗旱性弱)为材料,采用盆栽控水试验,设置3个干旱处理(轻度干旱、中度干旱、重度干旱)和正常灌水,研究了干旱胁迫对2个玉米品种气体交换、叶绿素荧光参数和渗透调节物质的影响。结果显示,重度干旱造成2个玉米品种叶片光合机构紊乱,破坏细胞膜完整性;同时增加了渗透调节物质,这对增强叶片的保水能力,维持光合速率有重要的作用。但与陕单902相比,干旱胁迫下郑单958表现出较高的最大净光合速率(Pn,max),表观量子效率(AQY),光饱和点(LSP),最大电子传递速率(Jmax),最大羧化速率(Vc,max),PSⅡ的实际量子产量(ΦPSⅡ)和光化学猝灭系数(qP);较高的脯氨酸(Pro)和可溶性糖含量(SS);较低的丙二醛含量(MDA)。这些结果表明,干旱胁迫下抗旱品种郑单958具有较强的渗透物质能力,减轻细胞膜质过氧化程度,维持较高的光合性能是其适应干旱环境的生理基础。

模拟喀斯特生境条件下干旱胁迫对青冈栎苗木的影响

为了研究喀斯特"双层"地质结构对植物的影响,以及在干旱环境下,喀斯特地区植物的生理变化与适应策略,建立"土壤层-岩石(石灰岩)层-岩溶水层"水分供应分层模拟柱,对‘土壤层’设置不同水分梯度,种植青冈栎(Cyclobalanopsis glauca)苗木进行干旱胁迫试验,测定青冈栎的叶面积、比叶面积、生物量、渗透调节物质含量、相对叶绿素含量。结果表明:在模拟柱‘岩溶水层’加水条件下,植物根系能下扎至‘岩溶水层’,‘土壤层’干旱胁迫对青冈栎的生理变化没有产生影响;在‘岩溶水层’无水条件下,青冈栎生理变化受‘土壤层’干旱胁迫影响显著,‘土壤层’水分含量越低,青冈栎的叶面积、生物量、叶绿素含量、叶片相对含水量越小,青冈栎干鲜比、根冠比、可溶性糖、丙二醛和脯氨酸含量越高。青冈栎幼苗利用岩溶水层水分是适应喀斯特干旱环境的重要策略。

辣椒开花结果期对干旱胁迫的形态与生理响应

在遮雨网室选用抗旱性较强的农城椒二号和抗旱性较弱的陕蔬2001,研究辣椒在轻度、中度和重度干旱胁迫下不同时间的生长、产量、渗透调节物质、保护酶活性的变化规律及其生理调节机制。结果表明:随干旱胁迫时间的延长,辣椒的株高、分枝数、叶面积、单位面积产量、叶绿素含量和叶片相对含水量的抗旱系数呈下降趋势,下降速率与干旱胁迫程度呈正相关,与品种的抗旱性呈负相关;脯氨酸、丙二醛含量和细胞膜透性相对值随干旱胁迫时间的延长呈上升趋势;POD、SOD、CAT活性和可溶性蛋白相对值随着干旱胁迫时间的延长先升高后下降,抗旱性强的材料增加幅度低于抗旱性弱的材料;可溶性糖含量的相对值在轻度和中度干旱胁迫下呈上升趋势,在重度干旱胁迫下呈上升—下降趋势,且抗旱性强的材料上升速度大于抗旱性弱的材料。相关分析表明,干旱胁迫下,产量与株高、分枝数、叶片叶绿素含量、叶面积、叶片相对含水量抗旱系数呈显著正相关;与细胞膜透性、CAT活性和可溶性蛋白含量抗旱系数呈显著负相关。主成分分析表明,用作辣椒抗旱性鉴定的主要指标是单株产量、株高、叶面积、分枝数、可溶性蛋白、可溶性糖、MDA、叶绿素含量和细胞膜透性及叶片相对含水量,叶片POD、SOD、CAT活性、脯氨酸含量可做为辣椒抗旱性鉴定的次要鉴选指标。

万寿菊属不同品种初花期抗旱特性分析

以万寿菊属(Tagetes)9个品种为试验材料,研究了自然持续干旱胁迫对它们初花期的花最大直径、叶色、旱害指数等形态指标以及叶绿素含量(Chl a+b,Ch a/b)、叶片相对含水量(RWC)、叶片保水力(WHC)、叶片和花的脯氨酸、可溶性糖和可溶性蛋白含量等生理指标的影响,以揭示其抗旱特性及其生理机制.结果显示:(1)持续6d干旱胁迫条件下,万寿菊9个品种花的最大直径显著降低,叶绿素含量和相对含水量均呈明显下降趋势.(2)万寿菊叶片的脯氨酸、可溶性蛋白和可溶性糖含量均呈上升趋势;而花的脯氨酸含量持续上升,可溶性蛋白含量呈下降趋势,但可溶性糖含量变化趋势复杂.(3)万寿菊旱害指数与其叶片相对含水量、叶绿素总含量、叶片和花的脯氨酸含量、叶片可溶性蛋白含量呈极显著相关.研究表明,抗旱性强的品种可以通过调节自身的渗透调节物质含量减轻干旱伤害;9个品种初花期抗旱性强弱依次为:珍妮>金门>鸿运>拳王>巨人>发现>小英雄>大英雄>迪阿哥.

干旱胁迫下叶面喷施褪黑素对滁菊幼苗生理生化特性的影响

以滁菊品种"金玉"幼苗为材料,通过日光温室内盆栽实验,在中度干旱胁迫条件下(土壤田间持水量的40%),研究叶面喷施外源褪黑素(MT,100μmol·L-1)对滁菊幼苗生长及生理生化特性的影响,探讨提高滁菊耐干旱性的新途径。结果表明:(1)与对照相比,干旱胁迫处理降低了滁菊叶片叶绿素含量、净光合速率和水分利用效率,提高了可溶性蛋白质、可溶性糖和脯氨酸含量,而叶片MDA含量和相对电导率显著增加,显著抑制了滁菊幼苗的生长。(2)在干旱胁迫条件下,外源MT可显著提高滁菊幼苗叶片脯氨酸、可溶性蛋白质和可溶性糖的含量,并显著降低了叶片相对电导率和MDA含量,使幼苗保持较高叶绿素含量和净光合速率。(3)与干旱胁迫处理相比,外源MT处理的滁菊地上部和根系干重、鲜重均显著增加。研究发现,外源褪黑素(MT)在一定程度上可通过促进滁菊幼苗渗透调节物质的积累,有效降低干旱胁迫对其细胞膜的伤害,维持其正常的细胞膜功能,保持其较高的光合速率和水分利用效率,从而增加其对干旱环境的适应性。

干旱条件下臭柏的生理生态对策

为了探讨臭柏(Sabina vulgaris)的耐旱生理生态适应对策,进行了长期的野外调查和室内模拟实验。野外调查是在毛乌素沙地的天然臭柏分布区内,设置固定样方,调查分析;室内实验是将臭柏插穗带往日本冈山大学,移植于砾耕栽培装置中,设置对照区,弱干旱胁迫区,强干旱胁迫区(培养液渗透势分别为0 MPa,-0.1 MPa和-0.3 MPa)3种处理进行长期的干旱胁迫室内模拟实验,研究各处理区臭柏的生理生态学特性,结果表明,在干旱胁迫条件下,臭柏表现出积极的生理生态适应对策:(1)在生长方面,通过降低密度、自然稀疏及下部枝叶干枯的方式,以牺牲局部,确保个体生存的生态策略,有效地利用资源,维持种群的生存。(2)在气体交换方面,气孔关闭,气体交换速率减缓,光合速率和蒸腾速率都下降,但是,与光合速率相比,由于蒸腾速率受到更强烈的抑制,水分利用率提高。(3)在吸水保水方面,通过渗透调节能力的增强,细胞壁弹性的降低,增强忍耐脱水能力和吸水能力;通过增加气孔密度,提高气孔调节的敏感性,增加角质层厚度,减少水分的散失;增强耐旱性。