Some factors affecting the storage of fresh breadfruit

Breadfruit (Artocarpus altilis (Park) Fosberg) is a highly perishable tropical fruit which can be packed in sealed polyethylene bags and stored under refrigeration. The storage period between harvesting and softening was greater for fruit harvested partially mature than fully mature and for fruit which were harvested by picking or catching rather than traditional procedures. In 4 storage trials and a single shipping trial, the majority of partially mature fruits harvested by picking were still firm after 15 days although a significant proportion had commenced softening.     

Some factors affecting the response of grapevines to ethephon

Factors influencing the effects of ethephon on fruit abscission and leaf senescence in several Vitis vinifera L. cultivars were studied under field conditions in a series of exploratory experiments. Cultivars appeared to vary greatly in their response to treatment. Ethephon concentration, surfactant concentration, fruit maturity, application conditions and degree of foliage wetting all influenced the degree of response.The experiments were not conducted on a common cultivar, thus limiting the conclusions which can be drawn. It is apparent from the results that a complexity of plant, environmental and application factors affect the response of grapevines to ethephon.     

In vitro regeneration and Agrobacterium mediated transformation in gladiolus

Summary

In vitro regeneration and transformation studies were conducted on two cultivars of gladiolus. Cormels of 1.0 to 1.5 cm diameter cut into 2–3 mm thick slices of top, middle and bottom, and in vitro derived bisected shoot tips were used as explants on MS medium supplemented with 18.6 μM kinetin for multiple shoot induction. Amongst the cormel slices, the top slice gave better shoot induction response of 89% with an average of 2.4 shoots per explant over both cultivars. In vitro derived bisected shoot tips were inoculated on the medium oriented cut-side up, cut-side down and vertically both with and without the cormel base attached. Bisected shoot tips without attached cormel base and inoculated in the cut-side down orientation showed an average of 90% shooting response. In vitro derived shoot tips were used as explants for transformation. Explants were wounded by scalpel and particle bombardment with 1.6 μm naked gold particles by the biolistic delivery system. The wounded explants, after 3 d of recovery period, were co-cultivated with Agrobacterium strain LBA4404 harbouring the binary vectors pBI141 and pTOK233 which contained gus reporter gene with rice actin and 35S promoters respectively. GUS expression frequencies of 5.3% and 23% was obtained from scalpel and particle bombardment wounded explants, respectively. Particle wounded explants showed an average of 63 and 103 GUS spots when co-cultivated with pBI141 and pTOK233 binary vectors respectively. Explants co-cultivated with pBI141, after three weeks of selection on antibiotic containing medium showed blue streaks of GUS expression. It was concluded that Agrobacterium could infect the monocot gladiolus and transform the tissue eficiently when tissues were prewounded with naked gold particles delivered by particle gun.     

Some factors affecting the growth rate of sporophores of the cultivated mushroom

The growth of sporophores of mushroom (Agaricus bisporus) was studied using the Gompertz growth curve, and the parameters of the curve were found to vary appreciably between experiments.Three factors were identified which are associated with an increase in growth rate. These are (i) the earliness of initiation of the sporophore, (ii) the removal of adjacent sporophores, and (iii) a decrease in the number of sporophores initiated.It is suggested that the growth rate of sporophores is dependent on the substrate density in the mycelium, and also that the initiation process might be less efficient than the growth process. The implications of these findings for a mathematical modelling approach to mushroom crop growth are discussed.     

影响转基因苹果试管微嫁接苗成活的因子

以转基因苹果组培苗嘎拉、王林、富士和乔纳金为试材,研究了影响转基因苹果试管微嫁接苗成活的几个因素。结果表明,以继代培养30d左右、生长健壮的组培苗嫁接成活率较高。适当提高嫁接苗所在培养基中BA质量浓度有利于嫁接成活率的提高,其中以MS+BA1.0mg/L+NAA0.05mg/L培养基中嫁接成活率最高。接穗以带2～4片叶片为宜。同时研究发现,不同转基因品种对嫁接成活率影响不显著。     

Factors affecting twin-scale propagation of narcissus

The effects of several factors on bulbil yields obtained by twin-scaling were examined in 4 narcissus cultivars (representing poeticus, trumpet and large-cup types). Bulbils were initiated on twin-scales prepared at any time of year, but grew satisfactorily only if twin-scaling was carried out between June and September. Large twin-scales initiated more bulbils, but smaller twin-scales were also effective propagules and gave high rates of multiplication and bulbils with high relative growth rates. Twin-scales cut from the outer-most scales initiated most bulbils, but more of those bulbils produced from the more central scales were recovered after 1 year; those from intermediate scales produced most and heaviest bulbils after 1 year. Partial loss of the basal plate had no effect on bulbil initiation. Optimum bulbil initiation, emergence and first-year recovery rates occurred following incubation at 15 or 20°C; at 25°C these responses were cultivar-dependent. Bulbil yield after 1 year was greater following incubation for 16 weeks compared with 12 weeks. There was little effect on bulbil yield of cold (9°C) or warm (35°C) treatments of the parent bulbs prior to twin-scaling, except for a marked reduction in the numbers of bulbils initiated when the warm treatment immediately preceded twin-scaling. When the propagules were grown on in a frost-free greenhouse (minimum, 5°C) bulbil yields were higher than from those grown either in a warm glasshouse (minimum, 18°C) or in the open; an initial cold period (5°C) given before the propagules were placed in the frost-free house also reduced yield.     

梨外植体组培褐变的影响因子及预防措施

以鸭梨、黄金梨、阿巴特梨和杜梨为试材,对梨组培过程中影响外植体褐化的因素及防褐措施进行了研究。结果表明,品种、采样时期以及外植体内酚类物质含量等因素都显著地影响材料褐化率。抗褐剂试验表明,培养基中添加0.2g/L的聚乙烯吡咯烷酮(PVP)或100mg/L抗坏血酸(Vc),或将外植体在200mg/L抗坏血酸水溶液中浸泡30min后接入添加2g/L活性炭的培养基,均能显著抑制鸭梨褐化的发生。低温试验表明,鸭梨外植体经4℃低温处理6h后接种,或接入初期在4℃低温中培养12～24h,褐化程度明显减轻。     

Nutritional and cultural factors affecting rooting of papaya (Carica papaya L.) in vitro

Summary

Experiments were conducted to optimize nutritional and cultural requirements for initiation and growth of roots on papaya in vitro. Axillary shoots were obtained from plants which had been sub-cultured monthly for two years. Root initiation was enhanced when 1 to 2 mm of stem base was removed and shoots were growing actively before transfer to the rooting medium. Decreasing daylength during incubation from 24 h to 12 h promoted root initiation. Within the day temperature range of 22 to 29°C, optimum rooting occurred at 27°C and higher temperatures produced higher mean root weights per shoot. High concentrations of growth factors and the absence of sucrose in the medium both reduced root initiation, however, varying the concentration of sucrose and removing growth factors affected mean root weight per shoot. All media contained a modified de Fossard et al. (1974) basal medium plus 10 μM IBA.     

The effect of various environmental factors on flowering of gladiolus. I. Light intensity

Light intensity is an important factor affecting the flowering of Gladiolus. Insufficient illumination from sprouting to the 4-leaf stage decreased flowering percentage. However, the inflorescences of those plants which did flower under conditions of low light intensity were normal and developed the full number of florets per spike. Plants at the 4–6 leaf stage were most sensitive to prevailing light conditions. Low light intensity during this period decreased both the percentage of flowering and the number of florets per spike. After this stage only the number of florets per spike was affected by insufficient light.     

In vitro propagation of watermelon

A 3-stage, in vitro propagation system for diploid watermelon (Citrullus lanatus (Thumb.) Matsum. and Nakai) has been developed which is also applicable to the economic production of triploid (seedless) watermelon transplants.Stage I involves the stimulation of axillary-bud development from excised seedling shoot tips (1–3 mm) by a high cytokinin (K)/low auxin (IAA) ratio (4.6 μmol/l K 0.28 μmol/l IAA) on a modified Linsmaier and Skoog medium. An average of 4.5 axillary shoots of sufficient size to subculture (> 15 mm) were obtained from each explant in 5 weeks. These shoots were induced to root during 3 weeks subculture on Stage II medium containing 11.5 μmol/l IAA. Well-rooted plantlets were successfully transplanted to a 1 : 1 peat : sand (v/v) substrate and gradually “hardened-off” to greenhouse conditions (Stage III) for 3 weeks, after which they could be transferred to field conditions.Alternatively, axillary shoots from Stage I could be returned to fresh media with 9.3 μmol/l K and 0.28 μmol/l IAA, where an average of 10.3 axillary shoots could be obtained after 5 weeks.Cost estimates for producing 10 000 finished transplants per week project an approximate cost of 16 dollar cents per transplant.     

In vitro propagation of spathiphyllum

An in vitro method for propagation of Spathiphyllum cultivar ‘Clevelandii’ is described as an alternative vegetative-propagation method.Leaves, inflorescences, peduncles, buds and stem pieces were tried as explants. Initiation and development of shoots did not occur when leaves and peduncles were used. In a few cases, it was possible to induce shoots from pieces of inflorescence explants. Buds and especially stem pieces were very suitable as explants, with shoots developing on the basal medium both with or without a cytokinin.Further multiplication of the shoots was optimal on the basal medium supplemented with 2 mg/l PBA. On this medium, the basal part of the old shoots became swollen and callus-like, and new shoots emerged from the callused area.Shoots developed roots very easily on the basal medium without hormone additives.     

Vegetative propagation of Chrysanthemum cinerariaefolium in vitro

In vitro cultivated capitulum explants of Pyrethrum (Chrysanthemum cinerariaefolium Vis.) were induced to develop shoots. These shoots were isolated, treated with auxin and transferred to unsterilized soil. Adventitious root formation occurred and viable plantlets were obtained. Shoot development of other plant species according to this procedure was realized.     

The effect of various environmental factors on flowering of gladiolus. IV. Interaction of environmental factors — general discussion

The present paper summarizes results which had been presented in the previous three papers of this series, concerning the sensitivity of Gladiolus plants to environmental factors at different stages of development. The interaction between irradiation and temperature and its effect on flower blasting is demonstrated by comparing the flowering of plants planted on three different dates in autumn and winter with total solar irradiance during the full period of development, or the sum irradiance during stages which are sensitive to irradiation.     

Environmental factors affecting ethephon in olive

Inconsistent results of ethephon in field experiments in olive (Olea europaea L.) are attributed to climatic differences and irrigation regimes.Physical measurements, using ¹⁴C-2-chloroethyl phosphonic acid (¹⁴C-CEPA) at pH 6.3 indicated 60% degradation within 5 h at 40° C. Rate of degradation at 20, 30, 40 and 50° C at relative humidities of 37 or 70% was higher than at similar temperatures at 3 or 93% relative humidities. Temperature-dependent degradation of ethephon was similar on the surface of detached leaves, intact plants or in the glass test tube.Non-irrigated trees responded better than irrigated trees to ethephon treatment. Uptake and translocation of ¹⁴C-CEPA as a function of the water content was measured in a model system of detached branches. Uptake of ¹⁴C-CEPA was increased and translocation decreased in partially desiccated branches. The increased uptake and decreased translocation in desiccated branches is in accordance with the response of non-irrigated trees in the field.     

The effect of various environmental factors on flowering of gladiolus. III. Temperature and moisture

Under conditions of low light intensity in winter, low temperatures (1–4°C) increase the occurrence of flower blasting. This chilling damage was observed at two developmental stages — immediately after planting and at the 7th leaf stage when spike emergence starts. Gladioli are extremely tolerant to high temperatures (up to 50 °C) as long as air humidity and soil moisture are at an optimum. The damaging effect of high temperature is generally indirect via its effect on plant water balance. Plants were directly damaged by high temperature during the period from planting to the first leaf stage. Decrease in soil moisture reduced flowering at most stages of development. The stages immediately after planting and just before spike emergence were the most sensitive.     

杏组织培养研究进展

综述了杏茎尖培养、胚培养、原生质体培养、离体根叶培养等方面的研究进展情况     

影响我国荔枝分布的关键气候要素分析

【目的】明确荔枝分布与气候要素关系,识别影响分布的关键气候因子。【方法】基于国家气象信息中心气候数据,应用Arc GIS9.3软件分析荔枝分布与气候要素关系,以SPSS软件中主成分方法识别影响分布的关键气候因子。【结果】我国野生荔枝分布范围较栽培荔枝要窄;野生荔枝适宜年均温为22.32℃,年极端最低温为1.33℃,≥10℃年积温为8 120.57℃,年降水量为1 665.17 mm,湿润度为9.41;栽培荔枝适宜年均温为20.61℃,年极端最低温为-0.94℃,≥10℃年积温为7 429.71℃,年降水量为1 573.51 mm,湿润度为9.85;野生荔枝适应气候要素极差比栽培荔枝要小。【结论】影响荔枝分布的关键气候因子首先是低温指标,其次是高温指标,再其次是降水量。结果对准确认识气候变化影响及科学区划等有重要意义。     

影响葡萄贮藏质量的几个要素

近年来,随着葡萄贮藏保鲜技术的大面积开发,葡萄保鲜业发展迅速,为广大果农带来了可观的经济效益,但并非都获得令人满意的效果。根据本人多年调查和体会,认为有几个关键的技术环节直接影响葡萄的贮藏质量。1、栽培技术方面葡萄贮藏性能的好与坏,首先取决于其本身的质量,而质量是由栽培管理水平决定的。所以,要提高葡萄的贮藏性能,必须改善栽培管理。目前看,主要有如下几个问题:     

影响梨树高接换种成活率因素探索试验

以大龄老品种梨树绵梨，子母梨等为砧树，高接丰水，新高，爱宕，绿宝石等新品种。经5年的观察试验，总结出了山岭地大龄梨树高接换种适宜的嫁接方法，砧树树龄，穗砧组合，单株适宜的嫁接头数和栽培管理技术，达到了2年恢复树冠，3年恢复产量，平均株产186.6kg，经济效益较改造前提高4.3倍。     

Factors affecting the quality and in vitro germination capacity of strawberry pollen

Summary

Poor pollen quality and germination capacity curtails early yield in strawberry. The aim of this study was to establish a reliable method for in vitro assessment of strawberry pollen germination ability and to investigate further the effects of photoperiod and gibberellin on pollen germination and quality. In the first part of the study, pollen from seven strawberry cultivars (Chandler, Selva, Tudla, Camarosa, Eris, Pajaro and Irvine) was collected and its germination capacity and incidence of deformed pollen grains assessed in vitro using the hanging-drop technique. Highest germination rates, in ‘Selva’, were observed in a nutrient medium of 10% sucrose. Addition of calcium nitrate to the medium decreased the germination percentages of all cultivars. There was no significant difference, on average, between the germination rate at 20° and 25°C. Genetic factors affected the incidence of deformed pollen grains significantly, with ‘Pajaro’ showing the highest percentage (76%). In the second part, groups of young strawberry plants, cultivar Seascape, grown either under natural early spring conditions or under long-day or short-day conditions were sprayed once with GA₃ at 0, 50, or 200 mg l^–1. Pollen germination and deformation and stamen length were assessed three months later. In plants of the first group, GA₃ at 50 mg l^–1 increased pollen germination and decreased the incidence of deformed pollen grains, while GA₃ at 200 mg l^–1 decreased pollen germination without affecting the formation of deformed pollen grains. Plants of the second group showed a higher rate of pollen germination under long than under short days. GA₃ at 200 mg l^–1 decreased pollen germination under either short- or long-day conditions compared with the controls but doubled the percentage of deformed pollen only under short days. Stamens in control plants grew four times as long under long- than short-day conditions. GA₃ did not affect stamen length under long days but significantly enhanced their growth under short days.