【作者】 张海亭；

【导师】 胡景江； 张林森；

【作者基本信息】 西北农林科技大学 ， 植物学， 2012， 硕士

【摘要】 以苹果砧木平邑甜茶（Malus hupehensis）幼苗为实验材料，采用盆栽控水的方法研究了水分胁迫条件下和不同施钾水平下幼苗的水分传导特征。同时以田间大树（苹果树）为材料，研究了分根灌溉对树体水力学特征影响，取得了以下研究结果：1、水分胁迫能够显著降低平邑甜茶根系、叶片、冠层导水率，叶片、冠层的叶比导水率，冠层的茎比导率；与正常水分状况相比，在中度和重度水分胁迫下叶片的叶比导水率分别下降了35%和29%。2、正常灌水时，施钾能够提高根系、冠层导水率，根系、叶片、冠层的叶比导水率，冠层的茎比导率。中度钾和高钾水平条件下，叶片叶比导水率与低钾水平的叶片叶比导水率相比分别提高了17%和降低了27%。在严重水分亏缺时，中度钾条件下气孔导度比低钾条件下增加了28%。水分胁迫导致气孔导度降低，而施钾素能在一定程度能缓解这种影响。3、对13年生富士苹果树在田间条件下进行全根干旱（NI）、分根灌溉（PDI）与常规灌溉（CI）处理，树体水势、气体交换、叶片和枝条导水特性进行测定分析，结果表明：三个处理的茎水势和叶水势在全天中的日变化呈“V”形，午后14点的水势值最低。各月份的茎水势、叶水势及其日变化为7月份到达最低值。4、随着干旱程度的增加，树体的叶片导水率和枝条导水率逐渐下降， PDI和NI处理的叶片导水率与CI处理相比降低了13.27%和42.01%，PDI和NI处理的枝条导水率与CI处理相比降低了3.01%和34.36%； PDI处理的叶比导水率和枝条叶比导水率出现升高，分别比CI与NI处理高出14.32%、14.43%和96.12%、16.55%。与CI和NI处理相比，PDI处理下有更大的叶比导水率，但是其RWC介于CI和NI处理之间，可以看出在一定RWC变化范围内，叶比导水率的增加是以牺牲部分叶片相对含水量为代价的。PDI处理的WUE较CI和NI处理显著提高了29.08%和26.82%，其最大净光合效率、表观量子效率和暗呼吸速率介于NI和CI之间。这表明在半干旱地区分根灌溉能够在不影响苹果树体生理指标的前提下，来提高水分利用效率和光能利用率。5、利用高压流速仪（HPFM）测定对平邑甜茶和楸子（Malus prunifolia，苹果砧木）在干旱条件下对根系水力结构及其PV曲线水分参数的影响，结果表明：干旱条件下，平邑甜茶和楸子的根系导水率、根系叶比导水率、根系茎比导水率均降低。但两砧木相比存在一定差异。在适宜水分和干旱条件下，平邑甜茶根系叶比导水率分别为楸子根系叶比导水率的95%和92%，平邑甜茶根系茎比导水率分别为楸子根系茎比导水率的52%和62%，楸子与平邑甜茶相比在根系茎比导水率和根系叶比导水率上出现了增加。干旱胁迫引起了根系导水率的下降，继而导致了地上部分气体交换受到影响。在2种水分条件下，楸子的ψs^tlp、ψs^sat、RWC^tlp、ROWC^tlp、ε＇值与平邑甜茶相比较均处于较低水平，Va值处在较高水平。对PV曲线水分参数进行隶属函数综合评价得出的值为楸子大于平邑甜茶，平邑甜茶和楸子之间b值差异不明显。在适宜水分和重度干旱条件下楸子所体现出的输水策略优于平邑甜茶。PV曲线水分参数同苹果砧木根系的水力结构一样能够随着植物所处的环境做出相应的调整。对于PV曲线水分参数研究发现，楸子在膨压保持方面与平邑甜茶相比，其抗旱性优于平邑甜茶。更多还原

【Abstract】 In this study, we use the material of apple rootstock Malus hupehensis seedlings toexperiment materials; use the method of pot water control under the condition of water stressand different potassium levels, study hydraulic structure characteristics of seedlings.Meanwhile, we use field tree （Fuji apple tree） for materials, research paritial rootzonesirrigation effects on the hydraulic characteristics of the tree. The following results wereobtained in this study:1. Water deficit greatly decreased hydraulic conductance of root, leaf and plant, leaf areaspecific conductance of leaf and plant, sapwood area specific conductance of plant of Malushupehensis, the leaf area specific conductance of leaf in the moderate and severe water stressreduced to the35%and29%of normal water conditions respectively.2. On the normal irrigation conditions and potassium addition can greatly enhancedhydraulic conductance of root and plant; greatly enhanced leaf area specific conductance ofroot, leaf and plant; also greatly enhanced sapwood area specific conductance of plant ofMalus hupehensis. The leaf area specific conductance of leaf in the moderate and highpotassium level were increased by17%and lowered27%compared with low potassium levelrespectively. In the severe water deficit, stomatal conductance in the moderate potassiumlevel increases by28%compared with low potassium level. Water deficit reduced stomatialconductance（GS）, however, potassium can decreased this result on some levels.3. Taking thirteen years Fuji apple trees as experiment material, we studied the effects ofall root drying irrigation（NI）, partial root zone irrigation（PDI）, conventional irrigation（CI）,three irrigation modes on the water potential, gas exchange, leaf and shoot hydraulicconductivity characteristics in the field conditons. The results indicated that leaf waterpotential and stem water potential reach the lowest valve in July of Fuji apple trees, diurnalvariations of water potential at reach the lowest valve in the14o ’clock, diurnal variations ofleaf water potential and stem water potential presented “V” type.4. The leaf hydraulic conductance and leaf area specific conductance have graduallydecline as the increase of the degree of drought, leaf hydraulic conductance of PDI and NIreduced13.27%and42.01%, shoot hydraulic conductance of PDI and NI reduced3.01%and34.36%compared with that of CI. But compared with CI and NI, leaf area specific conductance and shoot area specific conductance of PDI are enhanced by14.32%and14.43%,96.12%and16.55%, respectively. PDI has a bigger leaf area specific conductance comparedwith CI and NI, however, value of RWC is between the two, it showed that in a certain RWCrange, increase of leaf area specific conductance at the expense of RWC. Compared with CIand NI,WUE of PDI greatly improved29.08%and26.82%, and its max net photosyntheticrate, apparent quantum efficiemty and dark respiration rate are between the CI and NI. Thisshows in the semiarid areas of Northwest, PDI treatment can improve water use efficiencywithout influence the apple tree normal physiological indices and utilization rate of solarradiation.5. Measured with the high pressure flow meter （HPFM）, study the effects of water deficiton hydraulic architecture and pressure-volume curve water parameters of Malus hupehensisand Malus prunifolia. The results indicated that water deficit decreased hydraulic conductance,leaf area specific conductance, sapwood area specific conductance on root of Malushupehensis and Malus prunifolia. But there are certain differences compared to the rootstock.On the condition of suitable soil moisture and severe drought, leaf area specific conductanceon root of Malus hupehensis is95%and92%of Malus prunifolia respectively, sapwood areaspecific conductance on root of Malus hupehensis is52%and62%of Malus prunifoliarespectively, aspects of leaf area specific conductance and sapwood area specific conductanceon root, Malus prunifolia has larger value than Malus hupehensis. Drought stress maydecrease decreased hydraulic conductance of root, and then affected gas exchange of theground part. On the condition of suitable soil moisture and severe drought, compared valuesof ψs^tlp、ψs^sat、 RWC^tlp、 ROWC^tlp、ε＇of Malus prunifolia with Malus hupehensis, Malusprunifolia was on a low level, values of Va of Malus prunifolia was on a high level. Used bythe subordinate function comprehensive estimating analysis, pressure-volume curve waterparameters, value of Malus prunifolia was larger than Malus hupehensis’s, b value betweenMalus prunifolia and Malus hupehensis have no obvious difference. On the condition ofsuitable soil moisture and severe drought, Malus prunifolia reflects the water strategy whichwas better than Malus hupehensis. Pressure-volume curve water parameters in plants canadjust accordingly with environment. Studied with pressure-volume curve water parameters,Malus prunifolia is better than Malus hupehensis in the abilities of maintaining turgor of andthe drought resistance.更多还原