北方盆栽金桔元旦结果

一般人对辛勤一年培养的一盆金桔舍不得摘果,但是金桔过了春节,不落果也必须全摘下来,否则影响春季正常生长和开花坐果。     

早春哈密瓜留果节位研究

对早春哈密瓜吊蔓栽培分别于16、18、20、22和24节进行留果试验。结果表明:留果平均提早1个节位,果实发育期提前1.3d;18～24节位留果处理间产量差异不显著,与16节位留果差异显著;16～24节留果各处理间茎叶生长、果形指数、果肉厚度和可溶性固形物含量差异均不显著。     

苹果早期落果与新梢生长的关系

苹果“旭”夜间增加温度到25℃促进了早期落果。对早期落果和新梢生长之间的关系进行了观察。当温度增高时新梢生长比较旺盛,同时引起了落果。于是可下这样的结论:落果是由于新梢生长争夺营养物质而引起的。喷洒B_9能够抑制新稍生长使座果增加。新梢摘     

早春厚皮甜瓜留果节位研究

对早春厚皮甜瓜吊蔓栽培分别于12、13、14和15节进行留果试验。结果表明,平均留果提早1个节位,成熟期提前1d;13、14、15节留果产量差异不显著,与12节留果差异极显著。12~15节留果各处理甜瓜茎叶生长、果形指数、果肉厚度和可溶性固形物含量差异均不显著。     

留桩法摘梢对提高保果效能的观察

黄岩本地早和一些中迟熟温州蜜柑品系,都会因抽发夏梢而形成大量的生理落果,导致单株低产或不结果。目前对这些桔树的控梢保果方法,除了采用药剂与调节肥水等措施外,大多数群众还是采取及时摘梢,减少落果。可是,由于不注意摘梢方法,往往使保果的效果不好。为此,我们研究了不同的摘梢方法,并观察了其保果效能。认为“留桩法”摘梢的效果较好。     

早春不同田间管理对不知火桔橙采前落果和果实贮藏性的影响

调查了金堂县不知火桔橙生产中存在的问题,设置了4种不同田间管理方式和2种保鲜方法,研究其对不知火桔橙的采前落果和果实贮藏性的影响。试验结果表明,2月对桔园喷施两次杀菌剂含一次保果剂(2,4-D),可以有效地减轻采前落果并增强果实贮藏期间的耐贮性,明显降低贮藏期间的腐烂果率和干疤果率;2月对桔园施肥、灌水会加重采前落果和果实贮藏期间的干疤果比重,腐烂果比重也较高;贮藏前用2,4-D浸果能有效降低腐烂果率和干疤果率。     

富士苹果不同套袋方法的应用效果比较试验

以惠阳牌膜袋、膜＋纸袋、森全袋为试材，进行了富士苹果不同套袋方法的比较试验，结果表明，使用内膜外纸袋前期没有温室效应，摘袋后外界环境对果面影响较大，果实外观质量和商品率不如双套袋，比套纸袋略好；同时，由于落果率和投资提高，经济效益不及使用双套袋。     

PP333对柑桔生长和开花的影响

柑桔常因梢果争夺养分引起生理落果而减产,传统采用人工摘梢保果,但费工费时,难以实施。采用植物生长调节剂代替人工摘梢则为现代柑桔园管理的发展趋势。 PP333(多效唑)是80年代新开发的植物生长延     

沙田柚疏花疏果技术的研究

报道了6个处理：A、花蕾直径3～5mm时疏花序；B、第一次生理落果结束后，在果实横径0．5～1．0cm时疏果；C、A＋B；D、第一次生理落果结束后，果实横径2～3cm时疏果；E、不疏蕾不疏花，第二次生理落果结束后、果实横径3～5cm时疏果；CK、不疏蕾和花、不疏果，只疏畸形果、病虫果，对沙田柚坐果率、产量和商品果率的影响。结果表明，除处理B比D、CK显著提高坐果率，处理D、E显著提高商品果率以外，其它各处理间及各处理与CK间的坐果率、株产量与商品果率无显著差异。因此沙田柚的疏果宜在第一次生理落果结束后、果实横径约0．5～1．0cm时进行。     

冬枣落果原因及对策

<正>1冬枣生理落果的主要原因1.1枝、叶、根与花、果营养竞争7月上旬正值树体营养竞争期,此前新梢生长、根系生长、开花及坐果均消耗大量树体营养,枝、叶、根、果间养分的竞争激烈,营养分配不均衡,会引起大量落果。1.2树势影响花果发育树体衰弱、贮存营养不足、花芽分化质量差,造成落果。1.3果实个头不均匀果实个头不均匀,大果对营养竞争强烈,小果营养缺乏,造成落果。     

云南省河口县蕉园香蕉植株中氮、磷营养分布特征

以云南河口县蕉园巴西香蕉为试验材料,分析了不同生长期(营养生长期、花芽分化期、现蕾开花期、果实生长期)不同器官(根、茎、叶)氮、磷含量及其变化规律.结果表明:香蕉植株根、茎、叶在整个生长期氮(N)含量分别在0.496％～0.675％、0.864％～0.923％和1.096％～1.457％之间.磷含量(P2O5)分别在0.088％～0.224％、0.123％～0.394％和0.157％～0.351％之间.从不同器官看,在整个生育期中,含氮量总体表现为叶＞茎＞根.含磷量在花芽分化期与现蕾开花期:叶与茎＞根;营养生长期:茎＞叶＞根;果实生长期:叶＞茎＞根.     

Dry-matter partitioning in a tomato crop: Comparison of two simulation models

SUMMARY

TOMSIM(l.O) and TOMGRO(I.O) are two dynamic models for tomato growth and development. Their sub-models for dry-matter distribution between leaves, stem and fruits were compared and discussed. In both models the simulated dry-matter distribution is regulated by the relative sink strengths of the plant organs. These sink strengths are quantified by the potential growth rates of individual organs, i.e. the growth rates under conditions of non-limiting assimilate supply. This approach is general and not limited to the tomato crop. In TOMGRO(J.O), fruits, leaves and internodes stay within age classes and move from class to class during development, whereas in TOMSIM (1.0), record is kept of every fruit truss separately but leaves and internodes are lumped together (i.e. no record of weight or leaf area per age class as in TOMGRO(l.O)). In TOMSIM(1.0), vegetative sink strength is a constant, whereas in TOMGRO(l.0) it is calculated from potential area expansion rate of leaves and specific leaf area. In both models, the ratio between leaf growth and stem growth is constant. In TOMGRO(l.O) there is a feed-back mechanism which controls the vegetative/generative balance: a higher demand/supply ratio for assimilates induces higher fruit abortion rates. In TOMSIM(l.O) the number of fruits set per truss is not simulated, but is an input to the model. TOM SIM (1.0) functions representing flowering rate, fruit growth period, vegetative sink strength and fruit sink strength were compared with similar TOMGRO(l.O) functions, in their dependence on temperature and physiological plant age. A sensitivity analysis was made for the effects of temperature, flowering rate, and fruit and vegetative sink strengths on dry-matter distribution for both models. A validation of both models was based upon periodic destructive harvests in: 1) a greenhouse experiment in Wageningen, using a round tomato cultivar, consisting of a control treatment and a treatment where every second truss was removed at anthesis, and 2) two greenhouse experiments conducted in Montfavet, using a beefsteak tomato cultivar. Daily shoot dry-weight increase, average 24 h greenhouse temperatures and numbers of fruits set per truss (in TOMGRO(l.O) numbers of flowers per truss) were inputs to the models. In general dry-matter distribution was simulated well by both models for the cultivar and conditions where they were developed. TOMGRO(1.0)'s poor performance in one of the validations resulted from the absence of an assimilate storage pool. To achieve reasonable agreement between measurements and simulations for situations other than where the models were developed, parameter adjustments had to be made, most likely reflecting cultivar differences. Strong and weak points of both models are discussed.     

Abortion of reproductive organs in sweet pepper (Capsicum annuum L.): a review

Summary

Levels of abortion of reproductive organs (i.e., buds, flowers, and young fruits) in sweet pepper plants (Capsicum annuum L.) are high, and cyclical fluctuations occur in fruit set. Stages susceptible to abortion are very young buds (< 2.5 mm), buds close to anthesis, and flowers and fruits up to 14 d after anthesis. An overview of factors and processes involved in flower and fruit abortion in sweet peppers is presented. More light, higher CO₂ concentrations, and lower planting density, increase the availability of assimilates per plant, and decrease fruit abortion. The cyclical pattern in fruit set is caused by changes in demand for assimilates. High flower abortion occurs when fast growing fruit (at approx. 3 weeks after anthesis) are present, due to competition for assimilates. Fruit set increases when fast growing fruit are almost mature and have a low assimilate demand. Prior to abortion, auxin export from the reproductive organ diminishes, ethylene production increases, and lower levels of activity of sucrose-cleaving enzymes are found. Severe water stress and low nutrient supply also increase abortion levels. Low night- and high day-time temperatures hamper pollen development, causing low seed set, which can result in fruit abortion. Two theories have been used to explain abortion: unbalanced demand for and supply of assimilates, and hormonal dominance of developing fruit over young fruit. Attempts to prevent abortion or to diminish the cyclical pattern of fruit set have not yet been successful, but new suggestions are presented.     

Vegetative growth, flowering and leaf nutrient concentration of boronia as affected by nitrogen level and form

Boronia (Boronia megastigma Nees, family Rutaceae) is an Australian woody shrub, producing strongly scented flowers at nodes. Increasing N levels from 0 to 25 mM in the nutrient solution increased the production of nodes, lateral shoots from these nodes and further nodes on these lateral shoots. With the same level of N, the order of number of node and lateral shoot production by N form was: combined NH₄⁺plus NO₃⁻ > NH₄⁺alone > NO₃⁻ alone. This increase in the number of nodes subsequently translated into increased number of axils initiating flower buds and then into fully developed flowers. However, increasing N levels decreased the percentage of flower buds developing to anthesis and individual flower weight. These decreases were attributed to continued vegetative growth during flower development. Increasing N levels increased the leaf N concentration with the concentration in the order NH₄⁺ + NO₃⁻ > NH₄⁺ > NO₃⁻. Nitrogen form did not affect the leaf tissue concentration of P, K⁺, Ca²⁺ and Mg²⁺. At lower N levels, the concentrations of these nutrients in the leaf tissue were higher and may have reached toxic levels, causing toxicity symptoms on leaves. At higher N levels, the concentrations of these nutrients were diluted due to increased growth and no toxicity symptoms were produced.     

Phenology of strawberry guava (Psidium cattleianum) in ReÂunion Island

Summary

The phenology of wild stands of strawberry guava (Psidium cattleianum Sabine) was studied at 100, 480 and 720.m over 2 years in ReÂunion Island. The shoots bore flower buds at the basal nodes, and vegetative buds at the apical nodes. Trees produced vegetative growth from September to December, flowers from November to January and fruit from February to June. Shoot growth was earlier at 100 and 720.m the first year, but were synchronized in the second year. Flowering and fruiting were also earlier at 100.m. The intervals between shoot emergence and flowering, and flowering and fruit maturity were strongly related to temperature, with base temperatures of 5.58C and 2.68C, and heat units requirements of 675 and 2,5528C.d, respectively. The number of shoots, flowers and fruit per branch varied across sites and years, unrelated to temperature. However, production was significantly higher at 720.m. Production was much lower after a hurricane. Flowering (y) was related to shoot production per branch (x) (log(y)=111.33.log(x); r².=.0.78), whereas the fruit set rate was highly variable between trees (26±100%). The number of fruits per branch (1±6) was possibly related to poor shoot growth or fruit set, but unrelated to the timing of the phenological events. It is expected that commercial orchards would be more productive than feral stands.     

日光温室不同矮蔓型西葫芦商品瓜位置与化瓜关系分析

通过2年2点对4个不同矮蔓型西葫芦品种商品瓜位置与化瓜等指标进行了研究,结果表明,不同矮蔓型西葫芦品种商品瓜离生长点的距离不同,结果中期半矮蔓品种平均为20.9cm,矮蔓品种为14.9cm,这主要是由于节间长度不同引起。不同矮蔓型西葫芦品种的化瓜率都较高,达37.9%~40.3%,品种间差异不显著,半矮蔓品种化瓜主要在商品瓜下方,矮蔓品种主要在商品瓜上方;生育后期商品瓜位置与新生叶的产生正相关,半矮蔓品种商品瓜对新生叶产生抑制作用小,库之间的竞争是其化瓜的主要原因,矮蔓品种商品瓜对新生叶产生抑制作用大,源的供应不足是其化瓜的主要原因。建议在生产中通过控制节间长度调节营养生长与生殖生长的平衡。     

Changes in oleuropein levels during differentiation and development of floral buds in ‘Arbequina’ olives

Oleuropein is the most abundant biologically active phenolic compound in olives. It has been extensively studied for human health benefits but its role in plant development processes has received limited attention. Changes in the levels of oleuropein during early stages of flower formation and during fruit development and maturation were determined using high performance liquid chromatography. Oleuropein and other phenolic compounds were identified by comparing retention time and UV spectra with standard compounds using photodiode array detectors. Quantitative measurements were based on peak areas relative to standards. Oleuropein levels sharply decreased during the transition from vegetative to flower buds, consistent with earlier reports that higher levels of exogenously applied oleuropein inhibited flowering in Kalanchoe blossfeldiana. Oleuropein levels rapidly increased with the expansion of fertilized pistils and then sharply declined with fruit maturity. There was only a modest decline in oleuropein levels between immature and fully expanded leaves. Hesperidin, which occurs in relatively small amounts, also declined considerably during early floral buds formation. Maximum levels of verbascoside were found in fully developed green fruits while maximum levels of luteolin-7-O-glucoside and luteolin-4-O-glucoside were found in fully expanded leaves.     

Effects of growth retardants on inflorescence development in tomato

The growth retardant (2-chloroethyl)trimethylammonium chloride (chlormequat chloride), applied as a soil drench to young tomato plants (Lycopersicon esculentum Mill.), was effective in reducing the abortion of flower buds that occurred under winter conditions in the glasshouse. Application of chlormequat chloride also reduced flower abortion that occurred in response to a shading treatment or to high night temperatures. A second growth retardant, tributyl-2,4-dichlorobenzylphosphonium chloride (chlorphonium chloride), showed activity similar to that of chlormequat chloride. It is suggested that abortion of the flower buds occurred when vegetative parts of the shoot system were in competition with the inflorescence for metabolites or growth substances, and that the growth retardants acted to reduce or remove this competition.     

The Effects of Manurial Treatments on the Chemical Composition of Gooseberry Bushes.: I. Effects on Dry Matter,Ash and Ash Constituents of Leaves and Stems of Terminal Shoots and of Fruits; and on Total Nitrogen of Fruits.

Summary

The effects of different timings of fruit thinning at the lower nodes (nodes 4 to 7) on fruit growth and abortion at higher nodes were investigated in a gynoecious, parthenocarpic cultivar of cucumber (Cucumis sativus L.), ‘NK x AN8’. Fruits at the lower nodes were removed 0, 5, 10, 15 and 20 d after anthesis of flowers at node 8 (DAA₈).

Total leaf areas and growth patterns of individual fruit were then monitored. When fruits at nodes 4 to 7 were thinned 0 or 5 DAA₈, all fruits at nodes 8 to 12 grew to commercial size, without fruit abortion. When fruits were thinned 10 DAA₈, the fruits at nodes 8 to 12 ceased to grow after anthesis, but growth was restored a few days after fruit thinning. Fruit thinning at 15 or 20 DAA₈ forced most fruits at nodes 8 to 12 to abort, while fruits at node 13 and above ceased to grow for a while, but resumed growth after fruit thinning. In all treatments, total leaf area increased with time throughout the experiment. High fruit load depressed the rate of growth of leaf area slightly, 65 to 75 d after sowing. Fruit load (fresh weight) per leaf area was about 50 mg cm^–2 just before fruits at nodes 4 to7 were thinned at 20 DAA₈.These results suggest that fruit abortion occurs if fruits at the lower nodes persist for a long period, and fruits at the middle nodes senesce before enlargement. Fruit thinning at the lower nodes can restore the growth of fruits in the stagnant growth phase within 10 d.     

不同调控措施对山葡萄生理落果的影响

严重的生理落果会造成山葡萄产量及品质的下降。山葡萄花期之前采取疏花、摘心、喷施叶面肥及植物生长调节剂等调控措施,对提高山葡萄坐果有明显的促进作用。结果表明,花前留6片叶摘心、喷施0.2%硼酸和人工减掉花序长度的1/5,落果率分别为55.33%、47.96%和50.84%,均显著低于对照。