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土壤分水与毛白杨蒸腾耗水关系的研究 总被引：4，自引：0，他引：4
以不同水分条件下盆栽苗木和大苗幼林为材料，对土壤水分与毛白杨蒸腾耗水的关系进行了分析研究，并建立了蒸腾耗水量模型。结果表明，土壤水分含量与蒸腾耗水量之间呈极显著正相关，且土壤水分状况还影响蒸腾节律；蒸腾耗水量因不同的土壤水分条件、供水历程、气象等因素而具有不同的变化特点。 相似文献
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水分和热胁迫处理对4种针叶树苗木气体交换和水分利用效率的影响 总被引：24，自引：2，他引：24
以杉木、马尾松、花旗松和北美乔柏为研究对象 ,研究了水分和热胁迫对生长期间苗木的气体交换、瞬间水分利用效率和稳定碳同位素组成 (δ1 3C值 )等生理生态指标的影响 ,结果如下 :(1 )水分胁迫使杉木、马尾松、花旗松和北美乔柏 4个树种的净光合速率显著下降。但热胁迫只影响杉木和北美乔柏的净光合速率 ,对马尾松的净光合速率影响不大。 (2 )对针叶气孔导度的研究发现 ,水分和热胁迫均对马尾松苗木针叶气孔导度有显著影响 ,但对杉木和北美乔柏苗木针叶的气孔导度只有轻微影响。 (3)水分和热胁迫处理对马尾松苗木的瞬间水分利用效率有显著影响 ,但对杉木和北美乔柏的瞬间水分利用效率无显著影响。 (4 )水分胁迫处理对杉木、马尾松、花旗松和北美乔柏 4个树种的稳定碳同位素组成 (δ1 3C值 )均有显著影响 ,随着水分胁迫程度的加深 ,4个树种苗木针叶的δ1 3C值增大 (负值绝对值变小 ) ,说明其永久水分利用效率更高。 (5 )热胁迫对杉木和北美乔柏苗木针叶的δ1 3C值有显著影响 ,且在热胁迫下 ,两树种苗木针叶的δ1 3C值减小 (负值绝对值增大 ) ,即永久水分利用效率下降。但热胁迫对马尾松和花旗松苗木的δ1 3C值没有显著影响 相似文献
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通过对干旱区4种木本植物体内Na+,K+浓度和水分、光合等指标的测定、比较,分析盐分积累与其耐旱性的关系。结果表明:梭梭和柽柳能够吸收、积累较多的Na+,而花棒和沙枣组织Na+浓度相对较低;与花棒和沙枣相比,梭梭和柽柳具有较低的组织水势和渗透势、较小的蒸腾失水量和较大光合作用有效水势范围。表现为植株水势、渗透势和蒸腾失水量与其组织Na+浓度呈负相关,而光合作用有效水势范围大小则与其呈显著正相关。由此可见:盐分积累能够降低组织渗透势和水势、增强水分吸收的动力,同时还可以减少蒸腾耗水,有利于植株在低水势下维持较高的光合作用能力,即干旱地区的植物通过积盐可以增强其抗旱能力。 相似文献
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采用室内盆栽试验,研究不同程度水分胁迫24 d对新西伯利亚银白杨叶片光合生产力和渗透调节物质含量的影响.结果表明：水分胁迫抑制了新西伯利亚银白杨幼苗叶片的光合能力,提高了叶片细胞中可溶性蛋白质含量,并影响了叶片中可溶性糖含量.随着胁迫强度和胁迫时间的增加,叶片净光合速率、蒸腾速率和气孔导度均显著减小.叶片净光合速率与蒸腾速率和气孔导度呈极显著正相关关系,与土壤含水量呈显著正相关关系.气孔导度蒸与腾速率呈极显著正相关关系,与土壤含水量、可溶性糖含量呈显著正相关关系.蒸腾速率与可溶性糖含量呈显著正相关关系.在土壤相对含水量≥25％的条件下,净光合速率下降主要由气孔因素导致.在土壤相对含水量＜25％的条件下,净光合速率下降主要由非气孔限制导致. 相似文献
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以4年生曼地亚红豆杉扦插苗为试材,实验前1个月将苗木移栽至花盆中置于大棚内进行正常水分管理.将苗木分为3组,每组10株,3个重复,分别进行干旱胁迫.重度干旱(从试验开始时停止浇水),中度干旱(试验期间3d浇1次水,浇水量为对照的50％),对照(充足供水).在重度干旱和中度干旱下分别胁迫35 d,研究曼地亚红豆杉对不同程度干旱胁迫的生理响应,以分析曼地亚红豆杉的抗旱性及抗旱机理.结果表明,水分胁迫下曼地亚红豆杉PD、E、Gs与对照相比显著下降,Ci在胁迫初期升高,胁迫21d后下降.水分利用效率(RwuE)先升高后下降,羧化效率(RCE)显著下降.叶绿素a、叶绿素b和总叶绿素含量在胁迫后与对照没有显著差异;Fv/Fm在胁迫期间没有显著变化,而IP1随胁迫强度增加和胁迫时间延长显著下降.推测曼地亚红豆杉在干旱胁迫下叶绿素含量和光系统Ⅱ (PSII)光能转化能力保持相对稳定,对水分有较高的利用效率,引起光合下降的主要是非气孔因素,即羧化效率的显著下降.在水分胁迫条件下,曼地亚红豆杉SOD活性、POD活性,MDA含量、Pro含量都呈现先升后降的变化,说明曼地亚红豆杉在水分胁迫初期能通过增加保护酶活性来提高对逆境下产生的过氧化物的清除能力,同时增加细胞中游离脯氨酸等渗透调节物质来提高植株的吸水保水能力,维持自身水分平衡,具有较强的抗旱性. 相似文献
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土壤干旱胁迫对黄栌叶片光合性能的影响 总被引：1，自引：0，他引：1
为探索土壤干旱胁迫和光照强度对黄栌光合作用性能的影响规律,应用CIRAS-2型便携式光合作用系统,测定4种土壤水分（对照、轻度、中度和重度胁迫）处理下,3年生黄栌（Cotinuscoggygria var．cinerea）苗木叶片光合作用的光响应过程。结果表明：1）土壤干旱胁迫对黄栌叶片的光合性能参数具有明显影响,随着土壤水分胁迫的加剧,黄栌叶片的光合速率、蒸腾速率、光量子效率明显降低,光补偿点增高,叶片水分利用效率在轻度水分胁迫（土壤相对含水量60-65％）下的水平最高;2）黄栌叶片光合作用对强光胁迫的适应性较强,在较大幅度的强光（有效辐射强度1000-1800μmol·m^-1·s^-1）范围内,均能获得较高的光合速率和水分利用效率;3）黄栌光舍作用对弱光的光能吸收、转换和利用效率（光合量子效率）较低,并随土壤水分胁迫加剧而明显下降。 相似文献
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李吉跃 《中国林学(英文版)》1996,(2)
本文研究了多重复干旱循环对１年生北美短叶松（ＰｉｎｕｓｂａｎｋｓｉａｎａＬａｍｂ．）和黑云杉（Ｐｉｃｅａｍａｒｉａｎａ［Ｍｉｌ］Ｂ．Ｓ．Ｄ．）苗木的气体交换速率及水分利用效率的影响。结果表面，多重干旱循环对它们的气体交换（Ｃｓ，Ｐｎ，Ｔｒ）有显著影响（Ｐ＜０．５），而对其水分利用效率（ＷＵＥ）影响不大（Ｐ＞０．１）。尽管北美短叶松的气孔对轻度干旱胁迫不如黑云杉敏感，但是它对中度及严重干旱胁迫的敏感程度却高于黑云杉。在轻度及中度干旱胁迫下，北美短叶松的光合作用主要受非气孔因素的影响，而黑云杉则主要受气孔因素的影响。解除干旱胁迫后，黑云杉的气孔敏感性、光合能力及水分利用效率的恢复都要比北美短叶松更快．我们认为，延迟脱水是北美短叶松的主要耐旱机理，而忍耐脱水则是黑云杉重要的耐旱途径。轻度的干旱胁迫锻炼可以帮助北美短叶松在更严重的干旱胁迫下保持固有而较强的耐旱能力。然而，通过多重复干旱循环锻炼后黑云杉在改善耐旱能力的强度方面则大于北美短叶松 相似文献
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杨树无性系幼苗光合作用和PV水分参数对水分胁迫的响应 总被引：24，自引：0，他引：24
比较研究了不同水分条件下杨树2个无性系幼苗的生长、光合特性和多种水分参数等，探讨其对水分胁迫的适应机制。结果表明，水分胁迫下2个无性系幼苗的生长减慢．净光合速率降低，昭林杨6号受水分胁迫影响较小，欧美杨64号受水分胁迫影响较大。胁迫初期，2个无性系光合作用受气孔限制，胁迫后期及复水后的恢复期，光合作用受非气孔限制。胁迫时杨树呼吸速率降低，尤其是昭林杨6号，以保持碳平衡。胁迫时2个无性系的ψs^100、ψs^0、ROWC^0均降低，ψs^100与ψs^0差值增大，表明杨树可以通过渗透调节维持压力势，对水分胁迫作出适应性反应，与欧美杨64号相比昭林杨6号这种能力更强，表明其抗旱性强。 相似文献
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Effects of water stress on Haloxylon ammodendron seedlings in the desert region of Heihe inland river watershed, Gansu Province, China 总被引：1，自引：0，他引：1
LIUFa-min WUYan-qing SUJian-ping DUMing-wu 《林业研究》2003,14(3):197-201
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 decrease 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 water-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. 相似文献
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Stomatal conductance, transpiration and xylem pressure potential of African locust bean (Parkia biglobosa (Jacq.) Benth.) seedlings subjected from the sixth week after emergence to four weeks of continuous soil drought did not differ from those of well-watered, control plants until two-thirds of the available soil water had been used. In both well-watered and drought-treated plants, stomatal conductance was highest early in the day when vapor pressure deficits were low, but decreased sharply by midday when evaporative demand reached its highest value. There was no increase in stomatal conductance later in the day as vapor pressure deficit declined. The relationship between transpiration rate and xylem pressure potential showed non-linearity and hysteresis in both control and drought-treated plants, which seems to indicate that the plants had a substantial capacity to store water. The rate of leaf extension in African locust bean seedlings subjected to six consecutive 2-week cycles of soil drought declined relative to that of well-watered, control plants, whereas relative root extension increased. It appears that African locust bean seedlings minimized the impact of drought by: (1) restricting transpiration to the early part of the day when a high ratio of carbon gain to water loss can be achieved; (2) utilizing internally stored water during periods of rapid transpiration; (3) reducing the rate of leaf expansion and final leaf size in response to soil drought without reducing the rate of root extension, thereby reducing the ratio of transpiring leaf surface area to absorbing root surface area. 相似文献
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在温室内用盆栽法栽植了1年生茶条槭、山梨和山桃苗木,并采用4种土壤水分处理,土壤相对含水量分别为75.0%、61.1%、46.4%和35.4%。结果表明:随土壤含水量降低,3树种苗木净光合速率,蒸腾速率和气孔导度均下降,土壤含水量最低时,茶条槭苗木各生理指标降低幅度最大,山梨和山桃次之。茶条槭和山梨水分利用效率随土壤含水量的减少呈降低趋势,山桃水分利用效率呈升高趋势。水分胁迫下,3树种苗木根分配生物量显著增加。茶条槭在水分胁迫下,根冠比增加幅度最大,山梨次之,山桃最小。此外,茶条槭叶形态可塑性强,随土壤含水量降低,茶条槭单叶叶面积和总叶面积显著减小,叶厚度增加。山梨和山桃在水分胁迫下单叶叶面积及总叶面积无显著变化。综合3树种苗木在水分胁迫下的生理和形态指标及生物量分配的变化,茶条槭对水分胁迫的适应能力强于山桃和山梨。表3参31。 相似文献
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模拟降水量变化对毛乌素油蒿幼苗生物生态过程中的影响研究 总被引：10，自引：0，他引：10
毛乌素是中国干旱、半干旱沙区典型沙地，其中水分是最大限制因子，随着未来全球变化，尤其是降水变化进一步激烈，将给这里的陆地生态系统分布格局和生产力带来巨大影响，本文选择毛乌素沙地优势灌木油蒿为研究对象，人控４种降水量梯度来探讨油蒿幼苗的生理生态对降水量的响应。结果表明，不同施水量的油蒿幼苗净水合速率、蒸腾速率、气孔导度、胞间ＣＯ２浓度、叶片温度、光能利用率、水分利用率日变化动态存在明显差异，当少量施水时，幼苗受到明显水分胁迫，故而关闭气孔，降低气孔度和蒸腾速度，以免过多的蒸腾失水。当充分施水时，幼苗叶片气孔开放，提高气孔导率、胞间ＣＯ２浓度和蒸腾速率，降低叶片温度、以此提高光合作用。不同施水的油蒿幼苗表现出不同的生理生态适应策略，幼苗荧光效率随着施水量增大，从机理上解释了幼苗光合作用随着施水量的增加而增长；向后剔除变量分析表明，随着施水量的增加，限制幼苗净光合速度的主要因子逐渐减少。当充人地水时，幼苗主要受到光合有效辐射和叶片温度的限制。当中度施水时，幼苗主要受到蒸腾速率、胞间／大气ＣＯ２浓度差值的限制，不少量施水量时，幼苗主要受到蒸腾速率、气孔导度、胞间／大气ＣＯ２浓度差值、叶片／大气温度差值及其大气温度的限制。 相似文献
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对朝阳地区常见的3个品种枣苗(大平顶枣、金铃圆枣、三星大枣)2年生嫁接苗进行4个不同的土壤控水处理,测定出3个品种枣苗在不同水分胁迫条件下的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)等光合特性指标,并计算水分利用效率,以探讨水分胁迫对3个枣品种光合特性及水分利用率的影响,结果表明:土壤水分的变化与净光合速率和气孔导度的变化呈正比关系;在重度胁迫条件下,随着胁迫时间的增加,3个枣品种胞间CO2浓度值接近直线上升状态;随干旱胁迫强度加大,蒸腾速率呈下降趋势。三个枣品种抗旱性大小顺序为三星大枣金铃圆枣大平顶枣。 相似文献
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We examined the interactive effects of elevated CO2 concentration ([CO2]) and water stress on growth and physiology of 1-year-old peach (Prunus persica L.) seedlings grown in 10-dm3 pots in open-top chambers with ambient (350 micromol mol-1) or elevated (700 micromol mol-1) [CO2]. Seedlings were supplied weekly with a non-limiting nutrient solution. Water was withheld from half of the plants in each treatment for a 4-week drying cycle, to simulate a sudden and severe water stress during the phase of rapid plant growth. Throughout the growing season, seedlings in elevated [CO2] had higher assimilation rates, measured at the growth [CO2], than seedlings in ambient [CO2], and this caused an increase in total dry mass of about 33%. Stomatal conductance, total water uptake, leaf area and leaf number were unaffected by elevated [CO2]. Because seedlings in the two CO2 treatments had similar transpiration despite large differences in total dry mass, water-use efficiency (WUE) of well-watered and water-stressed seedlings grown in elevated [CO2] was an average of 51 and 63% higher, respectively, than WUE of comparable seedlings grown in ambient [CO2]. Elevated [CO2] enhanced total biomass of water-stressed seedlings by 31%, and thus ameliorated the effects of water limitation. However, the percentage increases in total dry mass between well-watered and water-stressed seedlings were similar in ambient (53%) and elevated (58%) [CO2], demonstrating that there was no interaction between elevated [CO2] and water stress. This finding should be considered when predicting responses of trees to global climate change in hot and dry environments, where predicted temperature increases will raise evaporative demands and exacerbate the effects of drought on tree growth. 相似文献
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WANGQing-cheng SUNZhi-hu ZHANGYan-dong 《林业研究》2003,14(4):280-284
One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moisture contents (75.0%,61.1%, 46.4% and 35.4%). The results showed that net photosynthesis rate (NPR), transpiration rate (TR) and stomatal conductance (Sc) of seedlings of the three species decreased with the decease of soil moisture content, and Amur maple seedlings had the greatest change in those physiological indices, followed by Ussurian pear, David peach. Amur maple and Ussurian pear seedlings also presented a decrease tendency in water use efficiency (WUE) under lower soil moisture content, whereas this was reversed for David peach. Under water stress the biomass allocation to seedling root had a significant increase for all the experimental species. As to root/shoot ratio, Amur maple seedlings had the biggest increase, while David peach had the smaliest increase. The leaf plasticity of Amur maple seedlings was greater, the leaf size and total leaf area decreased significantly as the stress was intensified. No significant change of leaf size and total leaf area was found in seedlings of Ussurian pear and David peach. It was concluded that Amur maple was more tolerant to soil moisture stress in comparison with David peach and Ussurian pear. 相似文献
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Photosynthetic and stomatal responses to a soil drying cycle were examined in half-sib seedlings of four walnut (Juglans nigra L.) families. Well-watered seedlings of an Iowa seed source had significantly higher rates of net photosynthesis than seedlings from New York or Michigan sources. This superior photosynthetic potential was associated with both greater stomatal conductance and mesophyll capacity for CO(2) fixation. In a drying soil, net photosynthesis and leaf conductance to water vapor of all families declined substantially, even under mild water stress. These responses were more strongly related to soil water status, as estimated by predawn leaf water potential, than to leaf water potential at the time of gas exchange measurement. There were no differences among families in the pattern of gas exchange response to developing water stress; however, families differed in capacity for recovery of gas exchange from water stress following rehydration. Sensitivity of photosynthesis of black walnut seedlings to water stress may be associated with poor growth and survival of this species in xeric habitats. 相似文献
19.
油茶不同叶龄叶片形态与光合参数的测定 总被引：1，自引：0，他引：1
为了探讨油茶叶片形态特征、光合特性与叶龄的相关性,从而为油茶的生产经营提供理论参考,利用CI-203叶面积分析仪和LI-6400便携式光合仪测定了油茶新梢不同叶龄叶片的形态特征和光合参数。结果表明:油茶叶面积和叶片鲜质量,从第1到第3位叶逐渐变大,又从第3到第7位叶逐渐减小;叶片的叶绿素含量和净光合速率均随着叶龄的增大而增大;叶龄与蒸腾速率和气孔导度均呈极显著正相关,而与胞间CO2浓度呈极显著负相关;叶片比叶面积与胞间CO2浓度间呈极显著正相关,而与净光合速率、蒸腾速率和气孔导度间均呈极显著负相关;叶片干物质含量比值与其净光合速率、气孔导度和蒸腾速率间均呈极显著负相关;叶片生长20 d,叶面积等形态特征基本发育完全,经过60 d的生长后,基本成为主要功能叶。 相似文献
20.
光叶子花不同叶位叶片叶绿素含量和光合作用研究 总被引：1，自引：0，他引：1
本文以光叶子花炼苗60 d组培苗为材料,对光叶子花不同叶位叶绿素含量、呼吸作用(Re)、气孔导度(Gs)、胞间CO2浓度(Ci)、净光合速(Pn)、蒸腾速率(Tr)、叶面饱和水汽压亏缺(Vpdl)等进行了测定。试验结果表明,光叶子花叶片单位重量和单位面积叶绿素含量、净光合速度和水分利用效率(WUE)均随叶位上升呈先增大后减小趋势变化,其最大值都出现在第6叶位叶片;叶片呼吸速率、气孔导度和蒸腾速率均随叶位上升而减小;叶片胞间CO2浓度随叶位上升呈先减小后增大变化;叶面饱和水汽压亏缺随叶位上升而增大。由于光叶子花中部叶片叶绿素含量、Pn和WUE相对较高,因此在今后的栽培管理中应对中部叶片加强保护。 相似文献