梨树在自然水分亏缺下的生理反应

１９９４～１９９６年对梨树在自然水分亏缺和水分充足条件下的主要水分生理参数、气孔相对开张度（ＲＳＯＤ）、蒸腾速率（Ｔｒ）和光合速率（Ｐｎ）进行了比较研究。结果表明，梨树属于低水势耐旱类型，在自然水分亏缺下，其叶水势（ψｗ）显著降低，膨压（ψｐ）明显增高，而ＲＳＯＤ、Ｔｒ和Ｐｎ则无显著变化。梨树具有明显的渗透调节和一定的弹性调节作用，在中度水分亏缺下，其渗透调节能力△π１００或△π０分别为０．４４ＭＰａ和０．７７ＭＰａ，弹性调节能力△｜β｜和△εｍａｘ分别为２．７８和３．１９。另外，在自然水分亏缺下，梨树叶片还具有较强的保水能力，反映在基本无变化的膨压消失点的相对含水量（Ｒ０）、叶表面水分散失率（ＷＬ０）和明显高于ＣＫ的一定ψｗ下的相对含水量（Ｒ）值以及无灌溉园较高的εｍａｘ或｜β｜等方面。     

果树叶螨

叶螨又名红蜘蛛，属蛛形纲，蜱螨目，叶螨科。叶螨以成虫、幼虫和若虫刺吸叶片上的汁液，造成叶片失绿、焦枯，甚至脱落。为害落叶果树的叶螨，主要有几下几种。一、种类与为害寄主（一）山楂叶螨：为害苹果、梨、山楂、桃、李、杏、樱桃等果树。（二）苹果全爪螨（苹果叶螨）：主要为害苹果，也可为害梨、桃、李、杏等果树。（三）苜蓿苔螨：为害苹果、梨等。（四）二斑叶螨：俗称白蜘蛛，食性较杂，为害苹果、梨、桃等果树，也可为害花卉、蔬菜、作物、杂草等。（五）、葡萄缺须螨：为害葡萄。二、形态特征（一）山楂叶螨成虫雌成虫体长０…     

宁夏果树种质资源保存与利用

宁夏果树种质资源保存与利用宁夏果树资源共有２５个属、７５个种、８３２份。其中，苹果２８２份、梨１１７份、葡萄２３８份、桃１０４份、李３４份、杏６７份。（１）种质资源引种保存我所果树品种资源圃面积７．８ｈｍ２，共保存６个树种，苹果（１６０个）、梨（１０...     

国外果树科技

国外果树科技日本１９９１年的果树栽培面积统计日本１９９１年的各种果树栽培面积及其与１９８２年的比较，苹果５３４００ｈｍ２（公顷），比１９８２年增加０．６％；梨２１２６０ｈｍ２，增加１．０％；葡萄２５９００ｈｍ２，减少１２．５％；桃１３５００ｈｍ２，减...     

重茬果园调换树种好

重茬果园合理调换树种。能较好地解决再植障碍问题。据试验，苹果茬植桃、李、杏、葡萄、核桃，枣茬植苹果、梨、葡萄、桃、李、杏，葡萄茬植苹果、梨、桃、李、杏，苗木生长均基本正常。桃茬栽植苹果时，则前期生长较慢，3a（年）后逐步正常。可见，重茬果园以合理调换树种为好。     

阜新市果树生产现状及发展战略

阜新市果树生产现状及发展战略霍庆贞（辽宁省阜新市果树技术指导站１．果树生产发展现状阜新果树栽培历史较久，资源丰富。主要树种有苹果、梨、山楂、葡萄。其次有枣、杏、桃、李等１０余种。据１９９５年末统计，全市果树栽培面积已达３９．５９万亩，水果产量达５００...     

叶面喷施抗蒸剂对苹果树水分状态的影响

研究了叶面喷施抗蒸剂对盆栽苹果水分状态的影响。结果表明，抗旱剂一号（主要成分为黄腐酸）可明显降低树体蒸腾（最低时为对照的３９．２１％）提高气孔阻力（最大时为对照的２４３．９６％）和叶片水势（一般比对照提高０．２－０．４ＭＰａ，最大０．７ＭＰａ）并对叶温未产生明显的影响（变化一般小于１℃）有效作用期长达１５ｄ以上，在果树旱期喷施，可明显改善树体水分状态，腐殖酸效果不明显。     

叶面喷施抗蒸剂对苹果树水分状态的影响

研究了叶面喷施抗蒸剂对盆栽苹果水分状态的影响。结果表明：抗旱剂一号（主要成分为黄腐酸）可明显降低树体蒸腾（最低时为对照的３９．２１％）、提高气孔阻力（最大时为对照的２４３．９６％）和叶片水势（一般比对照提高０．２－０．４ＭＰａ、最大０．７ＭＰａ），并对叶温未产生明显的影响（变化一般小于１℃），有效作用期长达１５ｄ以上。在果树旱期喷施，可明显改善树体水分状态。腐殖酸效果不明显。     

盐碱地栽植果树时的防盐措施

盐碱地栽植果树时的防盐措施刘新华（山东省聊城地区农科所２５２０５８）盐碱地栽培果树，是充分利用盐碱地、发展高效农业的有效途径之一。树种中以枣、梨、葡萄等抗盐碱能力强，苹果、桃、杏等果树抗盐碱能力差。梨树耐瘠薄、喜轻质土壤、经济价值高，以杜梨为砧木的鸭...     

山杏等砧木对仁用龙王帽杏生育状况的影响

关于苹果、葡萄等果树砧木的研究较多。关于杏树砧木的研究报道很少,有的报道指出,山杏［Ａ．ｖｕｌｇａｒｉｓＬａｍ．ｖａｒ．ａｎｓｕ（Ｍａｘｉｍ）］、西伯利亚杏（Ａ．ｓｉｂｉｒｉｃａＬａｍ．Ｖａｒ．ｓｉｂｉｒｉｃａ）和毛桃（Ａ．ｐｅｒｓｉｃａＬ．ｖａｒ．...     

Purple spot in loquat (Eriobotrya japonica Lindl.) is associated to changes in flesh-rind water relations during fruit development

Experiments were conducted to assess the link between purple spot in loquat fruit (Eriobotrya japonica Lindl.) and changes in the water relations of the flesh and the rind. Panicles were thinned to 1, 3 or 5 fruit or left unthinned (control), fruit wrapped in foil or exposed to the sun, or trees grown under plastic (night temperature >15 °C) or in the open (night temperature 5–3 °C) to induce different levels of the disorder. Typically, spotting increased with thinning (R² = 0.95), and was higher in exposed fruit (26.3% of fruit affected) than in wrapped fruit (nil), and higher with cool nights (16.2%) than with warm nights (2.7%). Mean tissue water potential (Ψ_w) was similar in the flesh and rind, whereas osmotic potential (π) was higher (less negative) in the flesh, and pressure potential (Ψ_p) lower in the flesh. There were no consistent effects of thinning on Ψ_w, whereas π of the rind decreased (more negative) with thinning during fruit color break. This response was associated with an increase in Ψ_p (more positive) in the rind at the same time. The external rind of exposed fruit had lower π than the external rind of warped fruit, and higher Ψ_p. Similarly, the fruit from trees grown under cool nights had lower rind π and higher rind Ψ_p than fruit under warm nights. These results suggest that low rind π and high rind Ψ_p are associated with purple spotting in loquat, and possibly reflect relatively high sugar concentrations in the flesh that increases the gradient of solute concentration between the flesh and the rind, making easy a dehydration process in the rind, which is responsible for purple spot.     

干旱过程中桃树茎和叶水势的变化

对田间生长的四年生桃树在充分灌水后的２２ ｄ 干旱周期内,分别在早上６∶００ 和中午１４∶００对茎、叶水势进行跟踪测定。同时测定了土壤充分湿润、中度水分亏缺及严重水分亏缺条件下上述指标的日变化。结果表明：在三种土壤水分条件下叶水势的变化幅度在０ ．２ ＭＰａ 左右,差异不明显;而午间茎水势则由土壤充分湿润时的－ ０．６ ＭＰａ 降至土壤水分严重亏缺时的－ １ ．８ ＭＰａ,下降了１ ．２ ＭＰａ。在整个干旱周期中,午间茎水势的变化虽受日蒸发量的影响,其变化趋势与土壤水势的变化趋势比较一致。随着干旱的加重,午间茎、叶水势之差即茎、叶水势梯度也出现极大变化。在土壤充分湿润时,茎叶水势梯度高达１ ．５ ＭＰａ,在土壤水分严重亏缺条件下,差异缩小为０。研究认为桃树外围新梢水势及茎、叶水势梯度的变化对土壤水分亏缺的反应比叶水势的变化更敏感,因此较适宜用作衡量果树水分亏缺程度的生理指标。     

核桃果实发育初期的水分状况

对在不同土壤水分条件下核桃枝条、叶片和果实水分含量动态与生长发育关系的研究结果表明,土壤供水不足时,树体水分亏缺,影响枝条生长和果实发育,降低坐果率.对有关水分生理指标测试表明,不同品种核桃叶水势(φW)日变化虽有差别,但相似,呈双峰型,叶φw愈低,晚上回升愈缓慢.叶φw日变化还受枝条上着生果实的影响,未着生果实枝条叶φw高于有果枝的.叶φw降低抑制光合产物的形成和累积.核桃蒸腾作用的日变化也呈双峰曲线,并与环境因子有密切关系.叶组织水分亏缺时,抗脱水能力强,具有一定的抗旱性能,晚熟品种优于早熟品种.     

A comparative study of young ‘Thompson Seedless’ grapevines (Vitis vinifera L.) under drip and furrow irrigation. II. Growth, water use efficiency and nitrogen partitioning

The response of 3-year-old grapevines (Vitis vinifera L. cultivar ‘Thompson Seedless’) to furrow and drip irrigation was quantified in terms of water status, growth, and water use efficiency (WUE). Drip irrigation was applied daily according to best estimates of vineyard evapotranspiration while furrow irrigations were applied when 50% of the plant available soilwater content had been depleted. Drip and furrow irrigated vines showed similar water status (midday leaf water potential, Ψ₁) and shoot growth patterns throughout the season. Dry weight partitioning was not significantly different between treatments but root mass was somewhat larger for the furrow than drip irrigated vines. Nitrogen concentrations of the fruit and roots were significantly (P < 0.05) less for the drip irrigated vines when compared with the furrow treatment. Similar WUE (kg water kg⁻¹ fresh fruit wt.) were obtained for both treatments indicating that furrow irrigation was as efficient as drip irrigation under the conditions of this study. The data indicate that drip irrigation may increase the potential for control of vine growth by making vines more dependent on irrigation and N fertilization than furrow irrigation.     

甜菜作为能源作物的优势及其发展前景

从种植,生产工艺,经济效益等方面论述了甜菜作为能源作物的优势,并讨论了其存在的问题及发展前景。     

不同砧木对苹果树水分状况年变化的影响

苹果树各器官水势的年变化中，大部时间乔砧树高于矮化中间砧树，与半矮化中间砧树差异较小，与矮化中间砧树差异较大。水势较低影响树体营养生长而有利生殖生长。     

Models of water competition between fruits and leaves on spurs of ‘Bartlett’ pear trees and its measurement by a heat-pulse method

Water streams through the conducting systems in spurs of ‘Bartlett’ pear trees were modelled in piped water-streams or electric currents, and measured by a heat-pulse method. Water-potential measurements showed that water potentials of stems (ψ_s), leaves (ψ_l) and fruits (ψ_f) were highest, lowest and intermediate, respectively, at mid-day throughout fruit growth. Retaining this condition (ψ_s >ψ_f >ψ_l), a model was constructed where streams of water through pipes connecting 3 tanks with different water-levels was analogous to water streams among 3 organs of a spur. It was then possible to estimate the possibility of water flowing from the fruit into the leaf against a reverse gradient of water-potential between the stem and the fruit. Another model used electric currents passing through 3 connected electric cells with different voltages. As the electric resistances of the 3 paths were equal, the voltage gradients toward each cell in the circuit were calculated using Kirchhoff's law. Replacing voltages by water potentials allowed the gradients of water potential toward each organ to be estimated, $\text{2}\text{3}\text{ψ}{}_{\mathrm{<mtext>l</mtext>}}\text{?}\text{1}\text{3}\text{(ψ}{}_{\mathrm{<mtext>s</mtext>}}\text{+ ψ}{}_{\mathrm{<mtext>f</mtext>}}\text{)}$ toward the leaf, $\text{2}\text{3}\text{ψ}{}_{\mathrm{<mtext>f</mtext>}}\text{?}\text{1}\text{3}\text{(ψ}{}_{\mathrm{<mtext>s</mtext>}}\text{+ ψ}{}_{\mathrm{<mtext>l</mtext>}}\text{)}$ toward the fruit and $\text{2}\text{3}\text{ψ}{}_{\mathrm{<mtext>s</mtext>}}\text{?}\text{1}\text{3}\text{(ψ}{}_{\mathrm{<mtext>l</mtext>}}\text{+ ψ}{}_{\mathrm{<mtext>f</mtext>}}\text{)}$ toward the stem of the spur. Adverse water fluxes from fruits (for instance, ?0.5 ml peduncle^?1 h^?1 at the maximum rate) were determined by a heat-pulse method at mid-day in early August. Demonstrations of water fluxes through the peduncles and the petioles by this method gave close agreement with results from the 2 models in relation to the diurnal shifts of direction of the water streams. The gradients of water potential estimated by the electric current model was closely related to water fluxes during the day (r = ?0.9832 for peduncles, r = ?0.9604 for petioles). Hydraulic conductivities (L_p) for petioles or peduncles were in the order of 10^?4 cm s^?1 bar^?1.     

水势和盐胁迫对拟南芥种子萌发和根部生长的影响

以拟南芥为试验材料,向培养基中添加不同浓度的NaCl模拟盐胁迫、不同比例的PEG-6000模拟水势胁迫,观察并记录种子萌发率、幼苗根长、幼苗存活率等生理指标,检测幼苗中丙二醛(MDA)含量,研究了盐胁迫和水势胁迫对拟南芥种子萌发及幼苗生长的影响,以期明确盐胁迫程度和水势影响拟南芥植株生理状态的规律,为水势和盐胁迫处理提供依据。结果表明:当NaCl浓度等于及高于150 mmol·L-1时,幼苗平均根长为5.2 mm,显著低于对照组(24.8 mm);幼苗平均存活率为52.1%,显著低于对照组(98.1%)。当水势等于及低于-0.7 MPa时,幼苗无侧根生长,平均存活率为89.2%,显著低于对照组(98.7%),由此可知,NaCl浓度150 mmol·L-1和水势-0.7 MPa是拟南芥胁迫处理的阈值,当NaCl浓度高于150 mmol·L-1,或水势低于-0.7 MPa时,拟南芥种子萌发及幼苗生长被明显抑制。     

不同光周期条件下羽扇豆的生长发育状况

羽扇豆为羽扇豆属的多年生草本植物,在植物的研究领域它是一种很重要的模式植物,已成为当今城市装饰的宠儿。本试验充分利用羽扇豆对光周期的敏感性,采用光周期调控措施,对其营养生长及生殖生长的情况进行系统的观测。具体办法实施采用2种措施,第1种为长日照,利用白灯泡每日2:00～6:00补光,第2种为短日照处理,利用遮光补每日17:30～8:30遮光。试验过程中,外部形态特征要观测其高度,真叶片数及冠幅。从而更充分更系统的掌握羽扇豆的生长规律,有效控制其花期的长短。     

浅析农地整理潜力评价

农地整理潜力评价是农地整理事业持续健康道路上的必要保证。本文在分析农地整理潜力评价相关理论基础上,针对农地整理的设计阶段、施工阶段、运营阶段3个大阶段开展农地整理潜力评价指标体系的研究。设计阶段从扩展潜力、强度潜力、管理潜力3个方面来反应,施工阶段从质量管理、进度管理、资金管理、合同和信息管理和安全管理来反映,运营阶段主要从运营管理制度的完备情况、运营管理组织结构情况、运营经费支持情况、运营管理重视度、农业生产投入几个方面来分析,最后得到农地整理潜力评价的指标体系。