Complementary genes for red flower colour in zonal pelargoniums

It is proposed that the inheritance of red flower colour in zonal pelargoniums is controlled by the interaction of two complementary genes, Rl/rl and R2/r2. The hypothesis was tested, and proven, by the observation of expected Mendelian segregation ratios following selfs and crosses within and between a wide range of red and non-red (salmon, pink and white) flowered plants. The relationship between red flower colours and non- red colours is one of epistasis and not one of dominance and recessiveness. Examples of all four of the expected red-flowered genotypes, and four out of the five non-red flowered genotypes, with respect to the two red genes, were discovered. Goodness of fit tests for the independent assortment of four other loci from that of the R2/r2 locus provided no evidence for linkage.     

Pelargonium net vein agent and pelargonium petal streak as beneficial infections of commercial pelargoniums

Pelargonium Net Vein Agent (PNVA) and Pelargonium Petal Streak Agent (PPSA) have been shown to be graft-transmissable, singly and together, to both ivy-leaf and zonal pelargoniums. In zonal pelargoniums, PNVA symptoms are seasonal; PPSA results in petal curling in some cultivars and in most petal streaking is absent or only on the lower petal surface. PNVA symptoms were stable in the ivy-leaf cultivars studied, as were those of PPSA. There was no interaction between PPSA and PNVA, doubly-infected ivy-leaf cultivars showing both symptom types.Symptoms induced by PNVA and PPSA were eliminated by meristem culture.The commercial potential for the exploitation of PPSA and PNVA is discussed.     

The effect of preservatives on water balance in cut clematis flowers

A positive water balance is crucial for longevity of cut shoots. When water loss by transpiration exceeds water uptake by cut flowers, wilting symptoms appear. Clematis is a very attractive plant which can be used as a cut flower provided that suitable cultivars are chosen. The vase life of four cultivars tested ranged between 6.7 days and 9.0 days and the standard preservative – 200 mg·dm^?3 8-hydroxyquinoline citrate (8HQC) plus 2% sucrose – prolonged it significantly in two cultivars, while 8HQC alone was efficient in only one. The preservatives delayed reduction in fresh weight. An enhancement of water uptake by the preservatives resulted in prolonged vase life of flowers in two cultivars. However, the effect of preservatives on transpiration was not related to longevity. In addition, longevity did not depend on the xylem vessel size: the cultivar with the longest vase life had the lowest average xylem vessel diameter while the cultivar with the largest vessels had an intermediate vase life. Preservatives did not always affect the number of blockages in xylem appearing during vase life. Generally, the effects of preservatives on the elements of water balance in cut shoots of clematis were not directly related to the postharvest longevity.     

氮素营养对切花月季产量的影响研究

研究不同氮素营养水平对切花月季产量的影响,结果表明,氮素对切花月季生产有显著影响。月施氮量为140mg/株时,‘Black Beauty’获得最高产量,其单株年产量达22.20枝,年产量可达320～344枝/m2。氮素水平过高或过低,均严重影响月季生产。适宜的氮肥水平可促进月季侧芽与水枝的萌发与成花,使得养分吸收与光合作用增强,从而促进月季的生长发育,提高产量。     

Formation of parthenocarpic fruit, undeveloped flowers and aborted flowers in tomato under moderately elevated temperatures

Incidence of parthenocarpic fruit, undeveloped flowers and flower abortion in tomato plants (Lycopersicon esculentum Mill.) were compared under optimal temperature (OT, 28/22°C day/night) and chronic, mild high temperature conditions (HT, 32/26°C). Seeded fruits were found only under OT conditions, where 37±9% of all flowers developed into seeded fruit. However, flower aborted was also higher under OT, with an additional 24±7% of flowers aborted under optimal temperature conditions, compared to only 4±1% of flowers aborted under HT conditions. Under HT, most flowers (53±8%) developed into parthenocarpic fruit, and the remainder (43±7%) stayed on the plant as undeveloped flowers. A slow transition of undeveloped flowers to parthenocarpic fruit was also observed under HT. Factors determining whether flowers abort, develop parthenocarpically, remain on the plant without developing further, or develop into seeded fruit were discussed in relation to carbohydrate availability and the presence of seeded fruit on the vine.     

美国黑莓大棚高产高效栽培技术

美国黑莓,群众俗称"黑草莓",为蔷薇科黑莓属多年生藤本鲜食水果.原产北美,是第3代新兴水果,目前风靡欧美.1995年从美国引种成功,1997年被枣庄市科委列为农业重点开发项目.1999年进行了黑莓大棚栽培试验,结果表明果实、果色、风味与露地栽培较为相似,667m2(1亩)产量达820 kg,浆果成熟期比露地栽培提早86天左右,售价比露地栽培增长10倍(40～60元/kg),经济效益显著.     

6种宿根花卉抗寒性比较研究

以玉簪等6种宿根花卉的功能叶为试材,研究不同低温胁迫条件下叶片形态及SOD活性、可溶性蛋白质含量、细胞膜透性的变化,分析各种类的半致死温度(LT50).结果表明,不同种类宿根花卉的抗寒性有着明显的差异,其抗寒性强弱依次为大花金鸡菊＞宽叶麦冬＞玉簪＞鸢尾＞白花三叶草＞萱草.     

The physiological responses of carnation cut flowers to exogenous nitric oxide

Nitric oxide (NO) is a highly reactive signaling molecule and plays a variety of physiological roles in plants. The research on the application of NO to postharvest preservation of flowers and fruits shows great promise in recent years. However, the physiological mechanism of exogenous NO to affect cut flowers is not very clear. Therefore, an experiment was conducted to study the effect of exogenous NO on the vase life and physiological basis of Dianthus caryophyllus L. variety ‘Monte’. In the present study, 0.1 mmol L⁻¹ sodium nitroprussiate (SNP) was used as the NO donor, and 5 μmol L⁻¹ methylene blue (MB-1) was used as its scavenger based on the preliminary experiment. We evaluated the physiological index including increase of stem weight, malondialdehyde (MDA) concentration and lipoxygenase (LOX) activity, and cell protection enzymes activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX). The results showed that exogenous NO could significantly extend the vase life of cut carnation flowers and markedly increase fresh mass. The balance of water metabolism and the activities of SOD, POD, CAT and APX also showed improvement, while the production of MDA content and LOX activity were obviously decreased. The results suggest that exogenous NO could delay petal wilting in carination cut flowers, maintain water metabolism, the antioxidative enzymes activity and mass-eliminate reactive oxygen species (ROS) and as well as cell membrane stability. Moreover, the results indicated that MB-1 had the ability to reverse the active effects of NO on different physiological indexes. Therefore, the vase life of cut carnation flowers was markedly extended by SNP treatment.     

The effect of micro-organisms on susceptibility to freezing-damage in petals of cut rose flowers

The susceptibility of cut rose flowers to freezing-damage at sub-zero temperatures was examined. A correlation was found between visible freezing-damage and electrolytic conductance of petal leachate; electrolytic conductance was therefore used to evaluate the extent of freezing-damage.Inoculation of flowers with microbial suspension rendered them more susceptible to freezing-damage. The antibiotic streptomycin reduced the susceptibility to freezing-damage of flowers inoculated with micro-organisms, but did not affect the susceptibility of freshly-cut, untreated flowers.The significance of these findings is discussed in relation to temperature management during storage of cut flowers. It is suggested that freezing-damage is influenced by the presence of bacteria which proliferate during later phases of flower development and act as ice nuclei in the flower.     

梨每花序花朵数量与植物激素的关系

为探明影响梨每花序花朵数量的因素,调查了230个梨品种每花序花朵数量,简析了每花序平均花朵数量的梨品种数量频度分布。并从中选取每花序花朵数量极端差异的2个品种‘黄金’梨和‘金星’梨,采用液相串联质谱法(LC-MS)测定其花芽ZT、IAA、ABA含量,分析其每花芽分化花朵数量与植物激素的关系。结果表明:在常见梨品种中每花序有5~9朵花,‘黄金’梨的最多,平均为11.5朵,‘金星’梨的最少,平均为3.6朵。在花芽分化中后期,‘黄金’梨花芽的ZT含量极显著高于‘金星’梨;花芽分化过程中,‘金星’梨花芽IAA含量始终极显著高于‘黄金’梨;2个梨品种花芽ABA含量差异不显著。综上,花芽分化中后期花芽内高含量的细胞分裂素有利于促迚花朵的分化。     

Production of fruits with attached flowers in zucchini squash is correlated with the arrest of maturation of female flowers

Summary

Results from two trials carried out under different environmental conditions indicated that the high temperatures reached in greenhouses during the Spring-Summer growing season are the main environmental factor inducing production of zucchini fruits with attached flowers. The fact that the incidence of this characteristic is genotypedependent, with the percentage of fruits with attached flowers varying from 1.4 – 73% among the different cultivars grown during the Spring-Summer season, provides an opportunity for direct counter-selection for this trait in current zucchini squash breeding programmes. High temperatures in the Spring-Summer growing season also induced male-ness in all the cultivars analysed, delaying the production of female flowers, and increasing the number of male flowers on the main stem. Indeed, those flowers that remained attached to harvested zucchini fruits were transformed into bisexual flowers, exhibiting different degrees of stamen development, and were arrested as immature, closed floral buds. A detailed analysis of the maturation and abscission times in female and male flowers of different zucchini cultivars indicated that, although abscission time did not differ, maturation time was longer in male than in female flowers. By comparing sexual expression in different cultivars in different environments, we concluded that inhibition of female flower bud maturation occurs concomitantly with a delay in flower abscission, a process accompanied by the conversion of the female bud into a bisexual bud. Given that Spring-Summer conditions promote the maturation of both female and male flowers, and that the arrest of female flower maturation and abscission are associated with floral sex determination, it is possible that the arrest of female flower maturation is not directly induced by high temperatures, but is mediated instead by hormones such as ethylene or gibberellins.     

The effect of emasculation on the endogenous cytokinin levels of cymbidium flowers

Removal of the pollinaria and anther caps of cymbidium flowers resulted in anthocyanin accumulation in the lips and columns of the flower, followed by the senescence of petals and sepals. These changes correlated well with a decrease in the endogenous cytokinin levels in all parts of the flowers after emasculation. While it is presently not known how senescence is initiated, it is significant that at least 6 different cytokinins appear to be present in the anthers and that the total cytokinin level of these structures is much higher than in the rest of the cymbidium flower. This in itself may have an important function in preventing the onset of senescence.     

Water relations and keeping-quality of cut Gerbera flowers. II. Water balance of ageing flowers

Time course of fresh weight (F.W.), water content as percentage of dry weight of petals (W.C.), maximal water content after saturation of petals (W.C._max), relative water content of petals (R.W.C.), absorption rate (abs.), transpiration rate, water potential of petals (ψ), stem flow resistance (R_stem) and flower developmental stage of cut Gerbera flowers in solutions with chemicals were determined. In a solution with silver nitrate, an increase of R_stem was evident after 4 days, resulting in a decrease of abs., F.W., W.C., R.W.C. and ψ. A constant pH of the vase water of 3.5 could prevent this increase in R_stem. The pH of the vase water was influenced by the flower itself.When the increase of R_stem was prevented, the absorption rate was higher than the transpiration rate during the first 5 days after cutting, which resulted in an increase of F.W., W.C. and R.W.C. After day 5, absorption was lower than transpiration, the F.W., W.C., W.C._max and R.W.C. decreased, while ψ remained steady. It is suggested that the water deficit-water potential relationships of the petals change with age, resulting in a lower water-holding capacity of the petals.     

Bud opening of cut liatris flowers

The possibility of bud opening of cut liatris flowers (Liatris spicata L.) harvested at a tight bud stage was examined. Of the different solutions tested, 5% sucrose together with 0.2% TOG germicide solution gave the best results as evaluated by vase-life and inflorescence development. The subsequent quality of the treated flowers was superior to that of non-treated flowers harvested at a commercial stage.When flowers were exposed to simulated air-shipment after treatment, the superiority of treated bud-stage flowers over commercially harvested ones was even greater.     

Ethylene evolution and sensitivity in cut orchid flowers

The effects of ethylene and the rate of ethylene production were studied in several orchid flowers. Orchid flowers showed a wide range of sensitivity to ethylene; Vanda ‘Miss Joaquim’ was most sensitive, Cattleya, Cymbidium and Paphiopedilum were less sensitive, while Dendrobium and Oncidium were not sensitive. Ethylene production in opened flowers was low, less than 1 nl/flower/h. In Cattleya, a peak in ethylene production was observed at the onset of senescence. Emasculated and/or pollinated flowers of Vanda, Cattleya and Paphiopedilum produced high levels of ethylene; Dendrobium did not react to these treatments in ethylene production.The anionic silver-thiosulfate complex (STS) was partially inhibitory to ethylene production in emasculated Cymbidium flowers, but appeared to stimulate the process in pollinated flowers. It was, however, effective in decreasing anthocyanin synthesis in both emasculated and pollinated Cymbidium flowers. In Cattleya, aminoxyacetic acid (AOA) and STS had no effect on longevity of cut flowers.     

Senescence of Dendrobium `Pompadour' flowers following pollination

Summary

Flowers of Dendrobium `Pompadour' developed premature petal and sepal senescence following pollination. Pollination induced an ethylene climacteric accompanied by a small respiratory climacteric, epinasty and increased flower or inflorescence fresh weight and water uptake. Pollination did not alter petal and sepal anthocyanin content and ion leakage, and lip, petal and sepal fresh weight and dry weight. The fresh weight and dry weight of stigmas (columns) together with pedicels increased significantly after pollination. Ovary growth of pollinated orchid flowers with petals and sepals intact was greater than that of pollinated orchid flowers without petals and sepals, while their water uptake was not significantly different.     

邻苯二酚对切花保鲜效果的影响

采用不同浓度的邻苯二酚及8-HQC和蔗糖组成的保鲜剂对香石竹、月季、换锦花、非洲菊进行保鲜处理,研究其对切花寿命的影响。结果表明:1m M邻苯二酚组成的保鲜剂可以显著延长香石竹、换锦花、非洲菊和月季切花的寿命。     

甜瓜雄花的几个胚胎学特征

为阐明甜瓜雄花的胚胎学特征,用光学显微技术观察雄花花粉和花药壁的发育过程。结果表明,花粉母细胞减数分裂伴随胼胝质壁发育,减数分裂产生的4个小孢子在共同的胼胝质壁中呈四面体形排列。成熟期花粉粒直径约45μm,积累大量脂滴,故属于脂质花粉。花药壁由外向内依次为表皮、药室内壁、中层和绒毡层,各含1层细胞;绒毡层在原位解体,为腺质绒毡层。表皮产生单细胞表皮毛,细胞膨大、伸长,细胞质浓,不含大液泡,仅含小液泡,生存至花粉成熟时期。     

闽南地区草本花卉的配置应用——以厦门植物园花卉园为例

草本花卉种类丰富、适应性强、栽培容易、便于管理,是园林绿化中的重要材料。针对其园林特色,结合厦门地区的资源情况,探讨草本花卉在不同的园林环境中的植物配置与应用,并以厦门植物园草本花卉园的建设为例,阐述其植物配置,营造色彩绚丽、种类丰富、风格各异的园林植物景观。     

The inheritance of two novel subgynoecious genes in cucumber (Cucumis sativus L.)

Cucumber (Cucumis sativus L.), which is a vegetable crop, has served as the model system for sex expression in flowering plants, and the inheritance of sex expression in cucumber is well documented. However, the genetics of subgynoecism expression in cucumber had rarely been described. In this study, we investigated the inheritance of subgynoecious traits in cucumber plants with the inbred cucumber lines of subgynoecious (C. sativus L. var sativus cv 97-17 and S-2-98) as the materials. Genetic analysis had showed the two subgynoecious inbred lines were controlled by one pair of recessive gene and one pair of incompletely dominant gene, which were designated presently as mod-F2 and Mod-F1, respectively. Furthermore, the mod-F2 and Mod-F1 loci, which enhance the intensity of femaleness, also inherited independently with F and M genes.