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盐分胁迫条件下苜蓿根系吸水特性的模拟与分析 总被引：5，自引：0，他引：5
体文借鉴Ｈｏｍａｅｅ有关盐分胁迫的部分试验研究结果及一种新的数值迭代反求方法，对无水分、养分限制条件下，Ｈｏｍａｅｅ苜蓿盐分胁迫试验中苜蓿根系的吸水规律进行了数值模拟与分析，提出了一种计算相对根长密度分布函数的简便计算方法，建立了盐分胁迫条件下苜蓿根系的吸水模型．结果表明：盐分的存在会显著降低苜蓿的根系吸水速率，当土壤溶液的电导率达到约５ｄＳ／ｍ时，将极大地影响苜蓿的根系吸水；本文提出的计算相对根长密度分布函数的计算方法较为简便、可靠；基于相对根长密度分布函数的吸水模型可以较好地模拟根系的吸水规律． 相似文献
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水分胁迫后复水冬小麦根系吸水的恢复 总被引：4，自引：1，他引：4
温室盆栽试验结果表明，水分胁迫使冬小麦根系吸水功能受到抑制，复水不能使之恢复到对照水平。水分胁迫后复水根系吸水功能的恢复与胁迫时期、胁迫持续时间及胁迫程度有关，在相同水分胁迫程度下早期比中后期水分胁迫后复水根系吸水功能恢复的程度低；水分胁迫持续时间的延长使根系吸水功能恢复程度进一步降低。水分胁迫程度的加重在不同水分胁迫时期对根系吸水的影响不同，起始于三叶期的重度水分胁迫后复水其根系吸水恢复程度可超过相应中度水分胁迫，说明早期水分胁迫程度的加重不会加剧对根系功能的不利影响。其他时期水分胁迫后复水，胁迫程度的加重对根系吸水恢复有负面影响。冬小麦最大根重与最大根系吸水强度的对比显示，中度水分胁迫下根系吸水功能的恢复主要依赖于复水对原有根系活性的激发，而重度水分胁迫下主要取决于新根的增加，胁迫后复水根系吸水功能的不可恢复是冬小麦产量降低的重要因素。 相似文献
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水分胁迫条件下绿洲农田冬小麦水分运移规律研究 总被引：5，自引：5，他引：5
以干旱区绿洲农田冬小麦水分胁迫试验为基础,研究了不同水分胁迫条件下的冬小麦生长发育、水分利用以及土壤水分运动特征,建立了含有根系吸水项的一维土壤水动力学模型,模拟了不同水分胁迫条件下冬小麦蒸腾、棵间蒸发、根系吸水、根系生长以及田间土壤水分运移过程。结果表明:在冬小麦生育前期、中期根系吸水主要在80cm以上,生育后期根系对下层土壤水分吸收量增加,但所占比例很小。根据实测根系生长资料分析水分胁迫下生育中期根系受到水分胁迫,在生育后期恢复灌水后根系早衰,生长缓慢;从胁迫程度上来说中度胁迫复水后的后效影响要大于重度胁迫处理。 相似文献
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盐胁迫下三角叶滨藜根系超滤特性的分析 总被引：2，自引：1，他引：1
对耐盐蔬菜三角叶滨藜(Atriplex triangularis)在盐胁迫下的蒸腾吸水量、Na+吸收和根系径向反射系数进行了测定,分析其根系超滤特性与植物耐盐性的关系。结果表明,随着盐胁迫强度的增加,三角叶滨藜的Na+吸收量逐渐增多、蒸腾吸水量和根系径向反射系数则逐渐降低;但以根外溶液盐浓度为基础的Na+相对吸收量却呈降低趋势,同时进入木质部的Na+的量也不随根的径向反射系数的减小而显著增多。说明三角叶滨藜在盐胁迫下一方面通过改变根系的超滤特性,降低根系径向反射系数来防止木质部拉力过大导致的木质部空化的危险,另一方面通过减少对盐分的吸收来避免盐分过多积累对植株的伤害。 相似文献
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土壤含水率剖面实测时间间隔T与实测点间距SI是影响平均根系吸水速率反求方法的2个主要因子。通过数值实验，首先探讨分析了T和SI的不同取值条件下，平均根系吸水速率模拟值的误差效应，从实际应用角度出发，若设定平均根系吸水速率的最大绝对误差≤0.0015 d-1，总体相对误差≤15%，则T和SI的选取最好能限制在如下范围之内：5 d≤T<15 d，SI<20 cm。应用上述检验分析结果，对两种水分胁迫条件下土柱实验中苗期冬小麦的根系吸水进行了模拟分析，结果表明：持续的水分胁迫将显著地降低冬小麦根系的吸水速率，抑制其根系的生长；当上部土层水分供应不足时，小麦的自我调节功能可导致根系扩大其吸水范围，向下部土层生长。 相似文献
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为了阐明小麦苗期耐低氮、低磷胁迫的生物学响应特征,以矮抗58品种为试验材料,采用水培试验法研究了小麦在不同营养环境中(全营养、低氮胁迫、低磷胁迫)的地上部生物学特性(地上部干重、株高、叶面积)、根系形态学特性(最大根长、总根数、根系总长度、根系干重和根冠比)和根系生理特性(根系活力、根系吸收面积),以及小麦苗期氮、磷素吸收与根系形态之间的关系。结果表明,在低氮和低磷胁迫下,小麦的株高、叶面积、茎叶干重、含氮量、根系干重、总根长、总根数及根冠比均明显降低,其中低磷胁迫下根系干重、总根长及根冠比的下降幅度大于低氮胁迫,低氮下最大根长的增加幅度较低磷增加7.3%;在低磷条件下小麦的含氮量下降了57.7%。低氮、低磷胁迫下小麦根系的总吸收面积、活性吸收面积及根系活力均明显降低;正常条件下的小麦氮、磷素吸收量与根系形态指标之间相关性较差,在低氮和低磷条件下小麦的氮、磷吸收量与根系干重、总根长、总吸收面积、活性吸收面积及根系活力呈极显著正相关。总之,该小麦品种根系对低磷环境反应较为敏感,而对低氮胁迫具有较好的适应性,小麦通过改变根系形态增加对低氮、磷胁迫的适应。 相似文献
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基于Hydrus-1D模型的玉米根系吸水影响因素分析 总被引：2，自引：1，他引：1
为探索土壤质地、植物生长状况和气象条件对不同土壤水分条件下根系吸水速率的影响机理,该文以相对根吸水速率与土壤含水率的关系衡量土壤水分有效性,利用Hydrus-1D模型模拟了3种土壤（壤黏土、黏壤土和砂壤土）中不同玉米生长状况（包括叶面积指数、根系深度和根系剖面分布）或蒸发力条件下根系吸水速率随含水率的动态变化,确定了不同条件下根系吸水速率开始降低的临界含水率。结果表明：土壤质地、植物的叶面积指数和根系分布及大气蒸发力都对根系吸水动态曲线的临界含水率有一定影响,其中根系深度和根系分布形状还影响根系吸水速率与含水率关系曲线的形状,但在3种土壤中,根系吸水速率的动态变化对植物生长和大气蒸发力的响应不同。总体而言,3种土壤临界含水率的大小是壤黏土＞黏壤土＞砂壤土;临界含水率随大气蒸发力的升高而升高,随根系深度和深层根系分布的增加而降低;各因子对玉米根系吸水影响程度的大小是土壤质地＞根系分布形状＞根系深度＞大气蒸发力＞叶面积指数。 相似文献
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盐分胁迫对菠菜生长和吸氮量的影响 总被引：1，自引：0，他引：1
为了研究盐分胁迫对菠菜生长和吸氮量的交互影响,在光培养室内开展了土柱栽培试验。试验设置3个灌溉水含盐量水平:0.87dSm-(1淡水,S0)、2.0dSm-(1盐分胁迫,S1)和5.0dSm-(1盐分胁迫,S2),2个氮肥水平:100kg Nhm-2(N1)和300kgNhm-(2N2)。本试验条件下,菠菜生育期为54天。在前44天,随着盐分胁迫程度增加,菠菜相对生长速率(relative growth rate,RGR)降低,其中在33~44天时,N1水平下,S0处理的RGR最大,为1.30×10-1gg-1day-1;在生育期的后10天,随着盐分胁迫增加,RGR升高。盐分胁迫导致菠菜吸氮量和干物质重下降。盐分胁迫和氮肥的交互影响使菠菜吸氮量降低47.02mgpot-1。菠菜吸氮量是其生长时间的二次函数。该研究表明,S2水平下,菠菜生育前期施肥量高,抑制作物生长。 相似文献
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根系吸水模型模拟覆膜旱作水稻气孔导度 总被引：2，自引：1，他引：1
为构建覆膜旱作水稻根系吸水模型,进一步改进气孔导度模型,该文在湖北十堰开展包含3个水分处理(淹水、覆膜湿润和覆膜旱作栽培)的田间试验,分析覆膜旱作水稻蒸腾(根系吸水)与根长之间的关系,在此基础上建立覆膜旱作水稻根系吸水模型,并将其代替彭曼(Penman-Monteith,PM)方程来估算蒸腾强度,进而与脱落酸(abscisic acid,ABA)参与调控的气孔导度模型耦合,模拟覆膜旱作条件下水稻气孔导度的日变化过程。结果表明,水稻蒸腾与根长呈线性正比关系(R~2=0.96,P0.05),据此建立的根系吸水模型可以较好地模拟覆膜旱作水稻的蒸腾(根系吸水)规律,使蒸腾强度模拟值和实测值间的相对误差基本控制在15%以内;经改进后的Tardieu-Davies气孔导度模型(TD模型)可有效描述不同土层根系吸水流中的ABA浓度及不同根系层ABA的合成对木质部蒸腾流中总ABA含量的贡献,可较好地模拟气孔导度的日变化过程。改进TD模型大大提高了模拟精度,使相对误差不超过7.0%。该研究可为覆膜旱作水稻生理节水机理和水分利用效率评估提供一定的理论依据。 相似文献
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Valère Cesse Mel Vincent Boubié Bado Saliou Ndiaye Koffi Djaman Delphine Aissata Bama Nati Baboucarr Manneh 《Communications in Soil Science and Plant Analysis》2019,50(11):1321-1329
Estimation of yield reduction in crop caused by the salinity stress is mostly based on variations of soil electrical conductivity and the severity of water stress. Crop response curves to salinity were developed without considering ion toxicity and nutritional imbalance in the plant. The objective of this study was to explore the possibility of using the ratio of the concentration of potassium by sodium in rice leaf (leaf-K/Na) to predict yield under the salinity stress. The rice (Oryza sativa L.) yield under fresh and saline condition and the leaf-K/Na related database was created. Data were collected from consecutive three seasons of a field experiment in the Africa Rice Center experimental farm in Senegal (16° 11? N, 16° 15?W). We studied the relationship between the relative yield (Yr), a ratio of yield under the salinity stress to the potential yield and the leaf-K/Na (x). Furthermore, we did regression analyses and F-test to determine the best fitting function. Results indicate that the exponential function [i.e. Yr = 100 exp (-b x)] was the best fitting model with the lowest root mean square error (9.683) and the highest R2 value (0.90). Example applications on independent data from published papers showed relatively good predictions, suggesting that the model can be used to predict rice yield in saline soils. 相似文献
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The effects of nitrogen (N) forms (ammonium- or nitrate-N) on plant growth under salinity stress [150 mmol sodium chloride (NaCl)] were studied in hydroponically cultured cotton. Net fluxes of sodium (Na+), ammonium (NH4+), and nitrate (NO3?) were also determined using the Non-Invasive Micro-Test Technology. Plant growth was impaired under salinity stress, but nitrate-fed plants were less sensitive to salinity than ammonium-fed plants due mainly to superior root growth by the nitrate-fed plants. The root length, root surface area, root volume, and root viability of seedlings treated with NO3-N were greater than those treated with NH4-N with or without salinity stress. Under salinity stress, the Na+ content of seedlings treated with NO3-N was lower than that in seedlings treated with NH4-N owing to higher root Na+ efflux. A lower net NO3? efflux was observed in roots of nitrate-fed plants relative to the net NH4+ efflux from roots of ammonium-fed plants. This resulted in much more nitrogen accumulation in different tissues, especially in leaves, thereby enhancing photosynthesis in nitrate-fed plants under salinity stress. Nitrate-N is superior to ammonium-N based on nitrogen uptake and cotton growth under salinity stress. 相似文献
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大气CO2浓度升高对小麦蒸腾耗水与根系吸水的影响 总被引：3，自引：3，他引：0
为了探索大气CO2浓度升高对作物蒸腾耗水与根系吸水的影响,该文布置了春小麦室内水培试验,试验共设置3个CO2浓度梯度(400±50、625±50、850±50μmol/mol),期间对各处理条件下小麦生长与蒸腾耗水的动态变化过程进行监测,包括水气交换、干物重、叶面积、根长、蒸腾速率等。试验结果表明:当CO2浓度从400μmol/mol升高至625、850μmol/mol时,短期(约3 d)内叶片气孔导度迅速降低,蒸腾耗水减弱,光合作用增强,导致水分利用效率升高;随着小麦被置于高CO2浓度条件下时间的延长,叶片气孔导度与蒸腾速率的降低幅度以及光合速率的增大幅度都逐渐缩小,即发生了CO2驯化现象。此时小麦生长仍然很旺盛,但蒸腾耗水并未发生显著变化,因此水分利用效率升高。CO2浓度升高可显著促进根系生长发育,导致单位根长潜在吸水系数显著降低(P<0.05),但其与单位根长氮含量之间仍呈线性正相关关系(R^2=0.83)。研究结果可为改进根系吸水模型与作物生长模型提供参考依据,并有助于系统理解土壤-作物-大气连续体。 相似文献
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Soil or foliar application of nitrogen (N) can increase plant growth and salinity tolerance in cotton, but a combination of both methods is seldom studied under salinity stress. A pot experiment was conducted to study the effects of soil application (S), foliar application (F), and a combination of both (S+F) with labeled nitrogen (15N) on cotton growth, N uptake and translocation under salinity stress (ECe = 12.5 dS m?1). Plant biomass, leaf area, leaf chlorophyll (Chl) content, leaf net photosynthetic (Pn) rate, levels of 15N and [Na+] and K+/ Na+ ratio in plant tissues were determined at 3, 7, 14 and 28 days after N application (DAN). Results showed that soil or foliar nitrogen fertilization improved plant biomass, leaf area per plant and leaf photosynthesis, and a combination of soil- plus foliar-applied N was superior to either S or F alone under salinity stress. Although foliar application favored a rapid accumulation of leaf N and soil application a rapid accumulation of root N, S+F enhanced N accumulation in both leaf and root under salinity stress. The combined N application also maintained significantly greater [K+] and K+/Na+ than either soil or foliar application alone. Therefore, the improved plant growth and salinity tolerance under S+F relative to soil or foliar N application alone was attributed to the increased total uptake of N, balanced N concentrations in different tissues through enhanced uptake and accumulation in both leaves and roots, and higher ratio of K+/Na+. 相似文献
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Fertilizer location modifies root zone salinity,root morphology,and water‐stress resistance of tree seedlings according to the watering regime in a dryland reforestation 
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下载免费PDF全文 There is a direct relationship between soil nutrient concentration in localized zones and root proliferation and elongation under well‐watered conditions. However, in field studies under semiarid conditions this relationship can change due to higher salt accumulation and soil dryness that affect root growth, water stress resistance, and seedling survival. We assessed the effect of different locations of fertilizer placement in the soil profile and water availability on root zone salinity, root development and ecophysiological responses of Quillaja saponaria Mol. after outplanting. A single dose (6 g L?1) of controlled‐release nitrogen fertilizer (CRFN) was placed at 0 cm (top layer), 15 cm (middle layer), or 30 cm (bottom layer) depth in the containers in a greenhouse, in addition to an unfertilized treatment (control). After 6 months, seedlings were transplanted to the field and subjected to weekly watering regimes (2 L plant?1 and unwatered). Morphological and ecophysiological parameters were periodically measured on seedlings, as well as soil electrical conductivity (EC). After 1 year, the shoot : root ratio of unwatered seedlings decreased as a function of CRFN placement depth, which was attributed to lower shoot growth and not to greater root growth. The root morphology of the bottom layer treatment was negatively affected by high EC in unwatered seedlings. Greater total root length and root volume of the middle layer treatment was found only when well‐watered; however, this did not contribute to improve physiological responses against water stress. The lowest EC and the highest photochemical efficiency, net photosynthesis, and stomatal conductance were shown by unfertilized seedlings, independent of water availability. Our findings suggest that varying depth of CRFN placement does not contribute significantly to improve root growth under water restriction. Water supplements, independently of the CRFN location in the substrate, contribute to decrease root zone salinity, and consequently, improve root volume growth. 相似文献
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The present study was conducted to assess the effect of soil salinity on yield attributes as well as nutrient accumulation in different plant parts of seven Brassica cultivars from two different species raised in pot culture experiment with two levels of salinity treatments along with control corresponding to soil electrical conductivity (EC) values of 1.65 (S0), 4.50 (S1) and 6.76 (S2) dS m?1. The experiment was consisted of twelve replications in a completely randomized design. Imposition of salinity stress affected various yield attributing characters including plant height, which ultimately led to severe yield reduction. However, tolerant cultivars, CS 52 and CS 54 performed better under salt treatment showing lesser yield loss. Salinity stress reduced the nitrogen (N) content in leaves of the Brassica plants, which reflected in decreased seed protein content. Reduced accumulation of iron (Fe), manganese (Mn) and zinc (Zn) was observed in leaf, stem and root at flowering and post-flowering stages, while CS 52 and CS 54 showed less reduction than susceptible cultivars under salinity stress. 相似文献