共查询到16条相似文献，搜索用时 125 毫秒
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该研究以春季温室番茄为试验材料,以筒栽和小区相结合的方法探索了番茄茎直径变化的机理与规律、外界环境因素对茎直径变化的影响以及如何消除气象因子对实测日最大收缩量（MDS）数值干扰等问题,目的在于为基于茎直径变化监测作物水分状况、实现自动灌溉的技术提供理论和实践依据。试验结果表明,番茄茎直径变化落后于叶水势变化,二者存在很好的相关性。番茄茎直径收缩过程是由韧皮部及木质部收缩同步构成,而恢复过程则是不同步的,木质部恢复较快。番茄盛果期蒸腾强度大于花果期蒸腾强度,蒸腾强度越大一天中最小茎直径出现的时间越晚,而其茎直径开始恢复的临界气孔导度值越小。番茄MDS的变化趋势和日均辐射的变化趋势一致,但变化幅度由土壤水分决定。当土壤相对含水率由田间持水率降至50%时,MDS随土壤水分的下降而变大,天气晴好时MDS能够很好的反映出土壤水分的差异;而当土壤相对含水率小于50%后,MDS随土壤水分的下降而变小。通过统计分析,由实测MDS与参照MDS相比的相对日最大收缩量（RMDS）指标基本上可以消除气象因子对监测结果的影响,稳定的反映土壤水分状况。 相似文献
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以番茄为试验材料,测定其在温室内基质栽培负水头供液条件下的日耗液量、空气相对湿度、气温和太阳辐射强度等气象因子数据,采用通径分析方法,建立多元回归模型,计算各气象因子对番茄日耗液量的直接通径系数、间接通径系数、决定系数和对回归方程估测可靠程度R~2的总贡献值。结果表明:作物系数和日平均太阳辐射强度的直接通径系数达到极显著水平(P0.01),2个因子的决定系数和对R~2总贡献值最大,是影响番茄日耗液量的重要因子;气象因子减少对番茄日耗液量影响的通径分析发现,敏感性最强的气象因子是日平均太阳辐射强度,其次分别是作物系数和日最高太阳辐射强度。 相似文献
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以番茄“MEISHUAI”品种为试验材料,研究了廊坊市春茬番茄温室内气温的影响因素、番茄生长与温度的关系及室温调控措施。结果表明:温室内日平均气温与温室内日平均10 cm土壤温度、日平均光合有效辐射及温室外日平均气温均存在极显著相关关系,相关系数分别为0.693、0.432和0.759;番茄茎粗、株高和果实橫纵径的生长量与积温成显著或极显著正相关。针对温室内温度过高的问题,提出了具体的室外气温调控指标和调控措施。 相似文献
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温室作物的耗水量与植株茎流变化密切相关,掌握温室作物茎流变化可提高灌溉制度的合理性。以温室滴灌番茄为研究对象,综合考虑气象因素和作物生长状况对番茄茎秆液流(T_f)变化的影响,探索了茎流计法监测温室番茄需水量的可行性,分析了不同典型天气条件下番茄T_f的变化规律及影响因素,考虑了叶面积指数(LAI)与T_f的关系,并与称重法进行了对比,最后采用通径分析法建立了气象因子与T_f的回归方程。结果表明,不同天气条件下,番茄茎秆的T_f表现为晴天多云天阴雨天。T_f与LAI密切相关,相关系数为0.77,达到了极显著水平(P0.01),此外,采用LAI对T_f进行标准化后可减少不同植株之间的个体差异。通径分析法结果表明,气象因子与T_f之间的关系可以表示为T_f=0.213 R_s+1.536 VPD-0.305,气温和风速对T_f的影响主要是通过太阳辐射(R_s)和水汽压差(VPD)实现的,R_s对T_f的影响大于VPD。研究为基于茎流计法测定温室滴灌番茄需水量提供了理论依据。 相似文献
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以温室春-夏季番茄为试验材料,采用小区试验方法,探讨了花果期和盛果期不同土壤水分条件下番茄叶片生理指标日变化特性、水分利用效率WUEL及生态因子间相关性。结果表明,番茄不同生育期生理指标日变化峰值时间不同;日均气孔导度、蒸腾速率随土壤水分的增加而变大,而日均光合速率最大值出现在70%土壤相对含水率的处理;两生育期蒸腾速率和光合速率受气孔调节的效应明显。在试验范围内,土壤水分越低,WUEL越高,番茄花果期WUEL较大。光合有效辐射是影响叶片光合速率重要生态因子。 相似文献
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在夏季玻璃温室内,进行了环境因子对番茄苗期生长与生理特性影响的试验,分析了环境因子(土壤含水量、太阳辐射、空气温度、空气相对湿度等)的变化对番茄苗期的影响.试验表明: 温室内太阳辐射、空气温度以及相对湿度的变化对番茄苗期的茎流量有着显著的影响,14:00时左右,茎流量达到最大;灌溉下限为田间持水量的80%时,番茄苗期长势最好. 相似文献
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夏玉米茎流和茎直径变化规律及其关系分析 总被引：3，自引：0，他引：3
通过对夏玉米生育期的茎直径微变化和茎流变化过程的监测,分析了茎直径微变化、茎流随土壤含水率和气象因子的变化规律,并对茎流与茎直径微变化之间的关系进行了分析。结果表明,茎直径微变化的日变化过程呈现明显的昼夜变化规律,白天收缩,夜间复原;茎直径日最大收缩量随含水量的升高而降低,可将其作为诊断作物水分状况的一个指标。茎流同样呈现明显的昼夜变化规律,白天茎流逐渐增大,在13:30左右达到最大值,然后减小。茎直径微变化、茎流的变化均受到太阳辐射、饱和水汽压差、空气温度、风速的影响。茎直径微变化与主要气象因子均呈负相关,茎流与其均为正相关关系。茎直径微变化与茎流之间呈负相关关系,且相关性很好。 相似文献
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根据避雨番茄筒栽试验结果,分析了不同旱渍胁迫组合及不同天气条件下的茎流速率日变化,采用通径分析和灰色关联分析的方法,计算了以太阳辐射、气温、相对湿度和土壤含水率4种环境影响指标为自变量对番茄茎流速率的相关系数、决定系数及灰色关联度.结果表明:不同天气下番茄茎流速率日变化规律差异显著,晴天下呈现峰值在正午的单峰型曲线,多云下呈现在10:00和14:00左右达到峰值的双峰型曲线,阴雨下茎流速率较小且波动不大;相同环境下不同旱渍组合的茎流速率日变化曲线可以反映水分的亏缺和渍害程度,轻度亏缺能够抵抗渍水的迫害,增大茎流速率,但是亏缺程度超过一定范围会显著降低茎流速率;通径分析与灰色关联分析的结果基本一致,影响茎流速率最大的是太阳辐射,决定系数达到0.91. 相似文献
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The sensitivity of stem diameter variations (SDV) measured with linear variable transducer (LVDT) sensors as indicators of plant water status in tomato was evaluated. Two tomato crops were grown sequentially in a sandy loam soil in an unheated plastic greenhouse. These were an autumn–winter tomato crop (autumn crop) and a spring–summer tomato crop (spring crop). One drying cycle of 61 days was imposed to the autumn crop in winter at 92 days after transplanting (DAT). Two drying cycles, each of 29 days, were applied to the spring crop, to young (58 DAT) and mature plants (121 DAT). For each drying cycle, four replicate plots did not receive irrigation, and four were well watered. During each drying cycle, LVDT sensors continuously measured SDV, and daily measurements were made of leaf (Ψ
leaf) and stem water potential (Ψ
stem). SDV data was interpreted using the SDV-derived indices, maximum daily shrinkage (MDS) and stem growth rate (SGR). The response of SDV-derived indices to water deficit differed with (1) climatic conditions during stress imposition and (2) crop age. In the winter drying cycle of the autumn crop, the responses of the SDV-derived indices to soil drying were relatively small and slower than Ψ
leaf and Ψ
stem. Under warmer conditions, the SDV-derived indices were much more responsive to soil drying. In rapidly growing young plants, where SDV was characterized by high SGR and small MDS, SGR was the most sensitive SDV-derived index. In more mature plants with little stem growth, MDS was the most sensitive SDV-derived index. In mature plants grown in warm to hot conditions, MDS (1) responded at a similar time or earlier than Ψ
leaf and Ψ
stem and (2) had larger “signal” values (ratio of values from unwatered to control plants) than Ψ
leaf and Ψ
stem. However, there was appreciably more “noise” (coefficient of variation, CV) associated with the SDV-derived indices, giving lower “sensitivity” values, determined from “signal” to “noise” ratios, than for Ψ
leaf and Ψ
stem. Regression analysis between MDS of well-watered plants and climatic variables gave best results for a linear relationship between MDS and daily maximum vapor pressure deficit. There were strong linear relationships between MDS and Ψ
leaf for each drying cycle. The slopes of these relationships differed with crop age indicating that there was no constant relationship between MDS and Ψ
leaf for a whole season. Overall these results demonstrated that MDS and SGR can be sensitive indicators of the water status of tomato crops under conditions of moderate to high evaporative demand. However, the variability associated with the SDV-derived indices and the changing MDS–Ψ
leaf relationship with crop age represent major issues regarding the development of irrigation scheduling protocols for tomato. 相似文献
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河套灌区玉米农田蒸散动态变化及其影响因子的通径分析 总被引：1，自引：0，他引：1
采用大型称重式蒸渗仪研究了内蒙古河套灌区玉米蒸散动态规律,并运用通径分析法探讨了玉米蒸散量ET与各影响因子间的相关关系.结果表明:充分灌溉处理下玉米生育期(播前-收获)累积蒸散量为593.72 mm,亏缺灌溉处理下为395.21 mm,日平均蒸散量分别为4.24和2.82 mm/d.由各生育期的分布情况可知苗期蒸散量最小,分别占全生育期的3.7%和5.8%;拔节期开始,蒸散量逐渐增大,在抽雄期达到峰值,2种处理总蒸散量分别为279.38和166.76 mm,日平均蒸散量分别为8.47和5.05 mm/d,分别占整个生育期蒸散总量的47.1%和42.2%.由小时尺度蒸散量变化规律可知,玉米日蒸散量变化规律表现为早晚低、中午高的“单峰型”曲线特征.通径分析表明:2种灌溉处理下,饱和水气压和平均气温对ET的综合决定能力较大,是2个主要的环境驱动因子;2种灌溉处理下对蒸散作用最小的因子均为风速,且风速对ET的影响以间接作用为主.影响河套灌区玉米蒸散的主要气象因子为饱和水气压与气温. 相似文献
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为探明滴灌条件下温室番茄植株茎流速率变化规律及其影响因素,本文采用Dynamax公司开发的包裹式茎流计观测日光温室番茄植株的茎流变化,研究茎流速率的变化规律及茎流速率监测结果的标准化处理技术,探索植株茎流与气象因子的相互关系,分析水分胁迫对番茄植株茎流速率的影响。研究表明,采用单位叶面积上的茎流速率表征茎流变化规律可在一定程度上降低因探头安装位置不同对监测结果的影响;在充分供水条件下,影响番茄植株茎流速率的主要因子是太阳辐射和饱和水气压差,番茄植株的日茎流速率与太阳辐射呈线性关系,与饱和差呈对数关系（R2＞0.90,P＜0.01）;土壤水分状况会明显影响番茄植株茎流状况,茎流速率随水分胁迫加剧而骤减。研究结果证明番茄植株茎流速率经标准化处理后可以真实的反映植株蒸腾规律。 相似文献
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在湖北省鄂州节水示范基地展开试验研究,利用LPS-05型植物生长检测仪对温室番茄的生理状况及室内环境进行实时监测,定性分析番茄主要器官(茎、叶)对室内温湿环境所响应的微动态变化,以作物自身生理状况为参考标准,确定了适宜番茄生长的温室环境指标。番茄茎粗生长最优的临界夜间最低温度为17.8℃;2类典型天气条件下叶表面露水汽化时间分别为09:30(晴)和11:30(阴雨),均比空气滞后1h;在充分灌水条件下,温室番茄发生水分胁迫时空气饱和水汽压差的临界值约为2.7kPa。 相似文献
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Could trunk diameter sensors be used in woody crops for irrigation scheduling? A review of current knowledge and future perspectives 总被引：3，自引：0，他引：3
M.F. Ortuño F. Moreno D.S. Intrigliolo C.D. Mellisho R. Domingo M.C. Ruiz-Sánchez J. Casadesus A. Torrecillas 《Agricultural Water Management》2010,97(1):1-35
The use of trunk diameter fluctuations and their derived parameters for irrigation scheduling in woody crops is reviewed. The strengths and weaknesses of these continuously measured plant-based water stress indicators compared with other discretely measured indicators for diagnosing plant water status in young and mature trees are discussed. Aspects such as sensor reading variability, signal intensity and the relationship between trunk diameter fluctuations and plant water status are analyzed in order to assess their usefulness as water stress indicators. The physiological significance of maximum and minimum daily trunk diameter and maximum daily trunk shrinkage (MDS) are also considered. Current knowledge of irrigation protocols and baselines for obtaining maximum daily trunk shrinkage reference values is discussed and new research objectives are proposed. We analyze the response of woody crops to continuous deficit irrigation scheduled by maintaining MDS signal intensity at threshold values to generate mild, moderate and severe water stress and assess the possibility of using linear variable displacement transducer (LVDT) sensors in trunk as a precision tool for regulated deficit irrigation scheduling. Finally, the possibility of using MDS signal intensity as a tool to match the irrigation regime to tree water requirements is also reviewed. 相似文献
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《Agricultural Water Management》2006,84(3):290-294
Measurements of maximum daily trunk shrinkage (MDS) were performed on adult olive (Olea europaea L. cv. Manzanillo) trees in an experimental farm in Seville (Spain). The objective was to study the feasibility of obtaining maximum daily trunk shrinkage baselines or reference values for use in irrigation scheduling. The trees were irrigated daily above their water requirements in order to obtain non-limiting soil water conditions. The results indicated it is possible to obtain baselines for MDS, despite a certain scattering of the data points representing the relations between MDS and the climatic variables (reference evapotranspiration, solar radiation, vapour pressure deficit and temperature). MDS behaviour was best correlated with midday vapour pressure deficit and midday air temperature (r2 = 0.83 and 0.79, respectively). 相似文献