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。     

几种果树水分生理指标的比较研究

以盆栽２年生苹果、杏、桃和葡萄为试材，研究了水分逆境对果树水分关系的形响及差异。从正常灌水（田间持水量８０％）所测定的萎蔫点相对合水量（ＲＷＣｐ）、萎蔫点水势（ψｗｐ）和总体原初渗透压（ψｚ０）判断， ４种果树抗旱性的顺序是：杏、桃＞苹果＞葡萄。干旱下测定的 ３种参量所反映的结果与上述一致。４种果树正常灌水处理弹性大小的顺序是：苹果＞杏＞葡萄＞桃，最大体积弹性模量（Ｅｖ０）分别是：３８．７、４４．９、５１．７、５５．６ＭＰａ。干旱条件下使苹果、杏弹性变差，葡萄、桃弹性增大。Ｅｖ０分别是：７１．７６、９０．６７、５４．０８和４０．４８ＭＰａ，说明ＣＫ弹性好坏不能反映对长期干旱的适应性。弹性系数与膨压（ψｐ）成显著直线正相关，说明弹性越好（Ｅｖ０越小），维持ψｐ能力越强，有利于气孔开张、维持光合。Ｅｖ０小者（苹果、杏）， Ｅｖ０随ＲＷＣ降低而缓慢降低，细胞伸缩范围大。 水分协迫下，苹果、各具有明显的渗透调节作用，苹果ψｗｐ和ψｚ０分别比ＣＫ下降０．５和０．４ＭＰａ，杏分别下降 ０． ６１和 ０． ５９ＭＰａ，葡萄只具有微弱的渗透调节能力，ψｗｐ和ψｚ０分别下降 ０． １６和 ０． １３ＭＰａ，桃无渗透调节能力。多一位处理使     

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。     

喷锌对蕹菜锌含量及产量的影响

不同喷施浓度及喷施次数对蕹菜产量及茎叶锌含量的影响结果表明：喷施０．０５％及０．１％的硫酸锌液均能提高蕹菜的产量，但以０．０５％的处理对产量的提高作用最明显，浓度超过０．１％时，对蕹菜生长有抑制作用提高喷锌浓度，蕹菜锌含量的增加为叶片大于茎；喷施１～２次，有明显的增产效果，喷施超过２次反而减产；随着喷施次数的增加，蕹菜锌含量也增加。     

高产素在巨峰葡萄上的应用

高产素是含有硼、锌、锰、钼、铜、铁、镁和螯合剂的微量元素肥料。１９９０—１９９２年，对巨峰葡萄每年喷施高产素１—３次，处理树比对照树的叶片增重３．２％—７．９％，叶片增厚５．６％—８．１％，主蔓径粗增大０．０１—０．１５ｃｍ，母蔓径粗增大０．０５—０．３１ｃｍ，坐果率提高２．９—３．２个百分点，果穗增重４．３％—２０．５％，３ａ（年）平均株产增长１１．６％—１７．０％，果实可溶性固形物含量增加０．２—２．５个百分点。叶面喷施高产素的投入与产出比为１：１０９．４，经济效益明显。     

预防亚美尼亚杏裂果试验初报

通过对亚美尼亚杏进行果实套袋（苹果膜袋和梨普通单层黄纸袋）和喷施化学试剂及植物生长调节剂来防止裂果发生的试验表明，套袋可以基本达到预防裂果的目的（裂果率1．0％～4．3％），但费时费力，成本高，不易推广；喷施0．3％氯化钙、50mg／L萘乙酸、0．4％硼酸、30mg／L赤霉素在很大程度上都能降低裂果率，而且可操作性强，其中，在果实第二次膨大期喷施0．4％硼酸防裂果效果最佳，裂果率可降至11．3％（对照为62．5％）。     

金冠苹果喷施稀土微肥试验

金冠苹果喷施稀土微肥试验金冠为８年生树。试验包括：①不同浓度试验，设０．０１％、０．０５％、０．１０％和０．２５％４个浓度处理，均于盛花期喷布；②不同喷布时期，设盛花期（４月２１日）喷１次、盛花期和果实膨大期（７月１８日）各喷１次、盛花期和着色前期（...     

洋葱在产籽时期的耐盐性

在用ＮａＣｌ、Ｎａ２Ｓｏ４、ＮｇＭ１２和ＭｇＳＯ４人工盐化了的花盆里研究了洋葱产籽时期的耐盐性。当土壤含盐量值分别超过４．０ｄＳｍ－１和６．０ｄＳｍ－１时，洋葱鳞茎的发芽率和营养生长下降。土壤含盐量（ＥＣｅ）每提高１单位（ｄＳｍ－１），洋葱种子产量则以６％的速率降低。在含盐量为８．１０ｄＳｍ－１时，洋葱种子产量与一个未盐化的对照比减少５０％。在盐渍状态下，种子千粒重仍不受影响。含盐量对种子发芽无不良作用。     

中草药熬制液配合真空脱气处理对金柑贮藏保鲜效果的研究

对金柑采用以高良姜、藿香为主的中草药熬制液浸果，用塑料薄膜小袋包装，在普通场所贮藏１００天，好果率达９０．９％，比对照提高１７．８个百分点。经中草药熬制液浸果后再进行真空度０．０５～０．０８ＭＰａ，２０分钟的真空短时脱气处理，则效果更好，不但好果率达９３．０％，比对照提高１９．９个百分点，而且果实维生素Ｃ、可溶性固形物、总糖、有机酸含量的保存率分别提高７．７、７．７、７．６和７．７个百分点，呼吸强度下降，有效地延长了金柑的贮藏寿命。     

赤霉素（GA3）对甜樱桃果实性状的影响

在果实生长第Ⅲ期的始期，用ＧＡ３溶液直接喷洒果实及叶片，果实单果重比对照增加１．２０３～２．６５５ｇ，果实直径比对照增加０．１４１～０．４５３ｃｍ，果汁的可溶性糖含量比对照提高０．１５％～２．２０％，Ｆ值均达到α＝０．０１水平．果实整齐度及着色程度均显著优于对照。综合果实性状，以１０×１Ｏ－６（１Ｏｐｐｍ）为最佳浓度。     

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。     

Synchronization of anthesis and enhancement of vegetative growth in coffee (Coffea arabica L.) following water stress during floral initiation

SUMMARY

The possibility of using water stress during floral initiation and development, to synchronize flowering in potted coffee trees of cvs Catuai Rojo and Mundo Novo was investigated. Moderate and severe cyclic and constant water stress had little effect on vegetative growth during floral initiation. However, upon rewatering, shoot growth was significantly greater in plants where leaf water potential [¨,] had declined to -2.5 MPa compared with plants where ¨, was maintained above -0.5 MPa. The period of floral initiation was not influenced by water stress and occurred only under short days (<12 h). In contrast, a y, of -2.5 MPa significantly reduced the number of inflorescences compared with plants maintained at a ¨| of -0.5 or -1.5 MPa. This reduction was associated with leaf drop in stressed plants. Therefore, regular irrigation during the period of floral initiation is recommended. Water stress (¨, of -1.5 or -2.5 MPa compared with -0.5 MPa) accelerated floral development with no deleterious effects on floral differentiation. Once flower buds are fully differentiated they enter dormancy and reach anthesis only if trees are stressed and rewa-tered. Flower buds remain dormant if trees are watered regularly or a constant water stress provided. A constant period of water stress in the late stages of floral development after floral initiation is complete provides a means of increasing the proportion of fully differentiated dormant flower buds (mature buds). This could represent a practical method to achieve synchronized flowering in field conditions where there is irrigation and a reliable dry season in the late stages of floral development.     

重水分胁迫下苹果树茎、叶水势的变化

对田间生长的3年生苹果树(红富士/M26/八棱海棠)在土壤干旱和湿润条件下的茎及叶片水势、气孔导度和净光合的日变化进行了测定。茎水势的测定采用外围新梢的直接取样测定法,以便同剪口处叶片的水势进行比较。测定结果表明,干旱土壤条件下的叶片水势稍低于土壤湿润的树,一般仅相差0.3MPa。而二个处理之间午间茎水势的差别则高达1～1.2MPa,表现出该指标对土壤干旱十分敏感。干旱条件下叶片气孔导度和净光合与土壤湿润的树也有明显差异。研究还发现,在水分严重亏缺条件下存在茎水势低于叶水势及一定压力下枝条木质部漏气现象。对这些现象的发生条件和可能原因进行了讨论。     

半根交替干旱对‘大久保’桃叶片中几种有机渗透调节物质的影响

 和良好水分条件的对照相比较, 半根交替干旱处理(ARS) 对‘大久保’桃叶片日出前水势无显著影响, 但显著高于全根干旱(WRS) 处理。WRS导致叶片中游离氨基酸、脯氨酸和可溶性糖含量显著增加和淀粉含量显著降低, 而ARS和对照之间叶片中游离氨基酸、脯氨酸、可溶性糖和淀粉含量均不存在显著性差别。此外, 叶片中游离氨基酸、脯氨酸和可溶性糖含量与日出前叶片水势呈显著或极显著负相关, 而淀粉含量与日出前叶片水势呈极显著正相关。上述结果表明, ARS条件下植株具有良好的水分供应能力, 并不存在积累上述有机物质进行渗透调节的现象。     

Productivity of olive trees with different water status and crop load

SUMMARY

A field experiment was conducted over two growing seasons to determine the combined effect of crop load and irrigation on yield components of olive trees (Olea europaea L. ‘Leccino’) planted at 6 m 3.8 m in a sandy-clay soil. Different crop loads were established by manual thinning of fruits. Drip irrigation was managed to maintain pre-dawn leaf water-potentials (PLWP) within the following ranges: (i) higher than –1.1 MPa (FI; fully irrigated); (ii) between –1.0 and –3.3 MPa (DI; deficit irrigated); or (iii) below –1.2 MPa, but not lower than –4.2 MPa (SI; severe deficit irrigated). The irrigation period lasted from 6 – 16 weeks after full bloom (AFB) in 2003, and from 5 – 19 weeks AFB in 2004. In 2003, full bloom was on 26 May; in 2004, it was on 3 June. Neither irrigation regime nor crop load affected flowering or flower quality the following Spring. The combined fruit yields [on a fresh weight (FW) basis] over both years in SI and DI trees were 49.0% and 81.6% of FI trees, respectively. The oil yields of SI and DI trees were 52.5% and 81.2% of FI trees, respectively. Fruit FWs in FI trees were greater than those of DI or SI trees at 8 weeks AFB. At harvest, FI trees bore the largest fruits, and SI trees the smallest fruits. The FWs of individual fruits at harvest in the FI and DI treatments decreased as crop load increased, but no such relationship was apparent for SI trees. The oil content of the mesocarp increased as PLWP increased from approx. –3.5 MPa to –1.5 MPa. The oil content of FI trees at harvest decreased from 53.1% to 45.7% dry weight as fresh fruit yield increased from 5 – 25 kg dm^–2 trunk cross-sectional area. However, crop load did not have any effect on the oil content of the mesocarp in DI trees. Fruit maturation was delayed by irrigation. Maturation index also decreased (indicating delayed maturation) as the crop load on FI or DI trees increased, but did not vary with crop level in SI trees.     

Phenology and drought affects the relationship between daily trunk shrinkage and midday stem water potential of peach trees

Summary

The relationship between maximum daily shrinkage in trunks (MDS), daily trunk growth (DTG), predawn water potential (Ψ_pd) and midday stem water potential (Ψ_stem) were studied in an irrigation experiment in peach trees. Control trees were irrigated to replace evapotranspiration, with trees receiving regulated deficit irrigation (RDI) watered at 35% of this rate during Stage II of fruit development and after harvest. The RDI trees were watered as controls during Stage III of fruit development. Minimum (Ψ_pd and Ψ_stem fell to –0.6.MPa and –1.2 MPa, respectively in RDI plots compared with –0.2 and –0.6 MPa in the controls. Trunk growth was less in the RDI plots than in the controls during drought. In contrast, MDS was higher when deficit irrigation was applied in the RDI trees. When site differences were considered the correlation between (Ψ_pd and accumulated trunk growth over an ample period was loose, while maximum daily shrinkage and midday stem water potential remarkably improved such a correlation. However, pooling all available data, the correlation between Ψ_stem and MDS was very poor (R²=0.44) and it substantially improved only when using data from specific phenological periods (i.e. R²=0.75). A seasonal drift in MDS values was observed and it was related to the seasonal changes in trunk growth rates, (i.e. highest shrinkage was found when growth rates were lowest). We concluded that phenology in combination with drought reduce the reliability of the water status information obtained from MDS.     

Responses of pepper to deficit irrigation for paprika production

Pepper (Capsicum annuum L.) production is normally carried out under irrigation as the crop is very susceptible to water shortage. Deficit irrigation strategies in pepper for paprika could increase production and facilitate mechanical harvest and, at the same time, save water. We conducted a field experiment that imposed water deficits, either during ripening (T1) or throughout the season (T2), and compared them to a fully irrigated control (T3). Stem water potential varied from −0.6 MPa in T3, early in the season to −1.5 MPa in T2 prior to harvest. Applied irrigation water for T1, T2, and T3 was 456, 346 and 480 mm, respectively. Water deficits depress leaf area and biomass production but did not affect the proportion of flowers that set fruit. Dry fruit weight in T2 at harvest was 66% of T3, but did not differ significantly between T1 and T3. However, commercial yield (based on colour production) was significantly higher in T3 than in the other two treatments, as the late water deficits imposed in T1 delayed harvest. We concluded that water deficits, either sustained or applied at fruit ripening, required for mechanical harvest do not hasten ripening and are detrimental to commercial yields and that pepper plants should be well supplied with water until harvest for maximum paprika production.     

The Reinvigoration of Apple Trees by the Inarching of Vigorous Rootstocks

Summary

The purpose of this research was to determine if established, orchard-grown apple trees that were con®ned in root-restricting membranes received adequate water for growth when irrigated. Previous data had shown positive effects of root restriction on reducing shoot extension growth in apple. Soil matric potential (Ψ_sm), leaf stomatal conductance (g) and leaf water potentials (Ψ_l) were measured over daily cycles during the period of maximum tree water use (July and August). Measurements were also made of the Ψ_sm and fruit size throughout the growing season. Daily and seasonal Ψ_sm showed that the soil within the root restricting membranes (+R) when irrigated (+I) remained closed to field capacity (<100 HPa), which was not the case for unirrigated soil within the membranes (-I +R). Ψ_l measured before dawn, showed that similar levels of drought stress were evident between irrigated and restricted (+I +R) and unrestricted (+I -R and -I -R) trees. The Ψ_sm, and Ψ_l for trees with roots within restricting membranes were significantly more negative, in the absence of irrigation (-I +R). Measurement of g showed that root restricted trees were transpiring at similar rates in the presence of irrigation (+I +R) as unrestricted trees (+I -R) with or without irrigation. Stomatal closure could not explain the increased Ψ_l observed for the restricted irrigated (+I +R) treatment compared with unrestricted (-R) trees. A reduced stomatal aperture was the most likely explanation for the reduction in growth previously observed with the restricted unirrigated trees. Fruit size was also affected by root restriction and the effect became greater as the roots became more restricted with tree age. Similarly, there was also a negative effect, in one year, of root restriction on fruit size at harvest, even in the presence of irrigation. Data show that reductions in soil water availability, Ψ_l and g, for the root-restricted trees (+I +R), were unlikely to be the causes for the previously observed reductions in shoot growth (tree size). These results imply that other factors were in operation, among which root-synthesized chemical regulators of shoot growth are the most likely candidates.     

JM提高苹果幼树抗旱性的研究初报

不同浓度ＪＭ（茉莉酸甲酯）处理明显提高干旱条件下盆栽‘首红’苹果幼树茎粗，促进地上部和根的干物质积累，显著提高叶片ＲＷＣ、游离脯氨酸含量和光合速率，对叶片气孔导度和蒸腾速率有不同程度的作用。ＪＭ３０和７０ｍｇ／Ｌ处理显著提高中度干旱条件下叶片ＳＯＤ活性，降低质膜透性、ＭＤＡ含量和叶细胞饱和脂肪酸含量，提高不饱和脂肪酸含量和不饱和脂肪酸指数。认为ＪＭ处理在一定程度上提高了苹果幼树的抗旱性。     

Citrus rootstock responses to water stress

Tolerance to drought-stress (DS) of the citrus rootstock Forner–Alcaide no. 5 (FA-5) was tested and compared with that of its parents, Cleopatra mandarin (CM) and Poncirus trifoliata (PT). Nine-month-old seedlings of CM, PT and FA-5 and 15-month-old grafted trees of ‘Valencia’ orange scions on these three rootstocks were cultivated in sand under glasshouse conditions and irrigated with a nutrient solution. Plants were drought-stressed by withholding irrigation until leaves were fully wilted. Survival time of both seedlings and grafted trees under DS was linked to the water extraction rate from the soil, which depended mainly on leaf biomass and on transpiration rate. Seedling responses to DS affecting leaf water relationships and gas exchange parameters varied among genotypes. FA-5 seedlings survived longer than the other seedlings, maintaining the highest levels of water potential, stomatal conductance, transpiration rate and net CO₂ assimilation towards the end of the experiment, when water stress was most severe. Thus, FA-5 was more resistant to DS than its parents (CM and PT). Moreover, rootstock affected the performance of grafted trees under water stress conditions. The higher drought tolerance induced by FA-5 rootstock could be related to the greater osmotic adjustment (OA), which was reflected by smaller reductions in leaf relative water content (RWC) and in higher turgor potentials and leaf gas exchange than the other rootstocks.