A Morphological Study of the 'Bullhead' Malformation in the Baccara Rose

The development of a malformed Baccara rose flower was comparedwith that of a normal one. A dormant apex completes most ofits vegetative differentiation before bud break. In transitionto flowering the dome-shaped apex flattens, and intense activityat its margins produces sepals, petals and stamens. Differencesin rates of cell division cause invagination of the centralpart of the receptacle. A ring-shaped non-functional nectaryis formed in the normal flower between the stamens and the carpels.This nectary is absent in the malformed flower. Instead, secondaryflorets bearing mainly carpels proliferate in this region.     

The Water Balance of Cut Rose Flowers

A sharp decline in water potential of petal tissue associated with wilting of cut rose flowers is described. Such a decline did not develop in senescing intact flowers. A circadian rhythm in water absorption by cut flowers was observed. The decline in fresh weight observed in the last phase of the vase life of cut flowers occurred earlier in a short-lived cultivar than in a longer-lived one. A decline in potential conductivity to water was observed with time in stems of cut roses. Concomitantly cellulase activity increased after cutting. Flowers held in cellulase solution wilted earlier than the controls. However, no difference was found in these two parameters between two cultivars differing in their longevity. The difference in longevity between the two cultivars was large especially under conditions promoting high transpiration rates, and was narrowed when flowers were either held in mild conditions, or the leaves were stripped off. Although stomates were equally open in intact flowers of the two cultivars, in cut flower shoots of the short-lived cultivar stomates were more widely open. In accordance transpiration rates were higher, and wilting occurred earlier in the short-lived cultivar than in the long-lived one. It is concluded that the earlier wilting of cut flowers of the short-lived cultivar is mainly due to lower ability to close stomates in response to water stress conditions, and not to earlier formation of vascular blockage.     

Respiration, Carbon Balance and Translocation of Dry Matter in the Corolla of Rose Flowers

The effects of import of dry matter from the leaves on respiration,metabolism of carbohydrates and development of the corolla werestudied in intact flowering rose shoots and compared with cutflowering shoots bearing either seven leaves on 45 cm stemsor two leaves on 30 cm stems. Over 4 days, corollas of two-leaf shoots imported and respiredless carbon than either the intact or the seven-leaf shootsand they developed more slowly. Starch levels in the corollaat the end of this time depended on the stage at which it wascut; more advanced flowers (stage 3–4) tended to losestarch whereas less advanced ones (stage 1–2) tended toaccumulate it. Total carbohydrate in the corolla was dependenton leaf number. Loss of d. wt of leaves indicated that they provided dry matterto the corollas even in cut shoots, and this observation wassupported by the recovery of ¹⁴C-leaf assimilate from corollas.The depletion of dry matter from leaves and the slight delayin corolla development of the two-leaf cut shoots suggest thata dynamic source-sink (leaves—corolla) relationship existsin the senescing cut rose as in the intact rose. Rosa sp, corolla, respiration, carbon balance, translocation     

The Action of Kinetin in Improving the Water Balance and Delaying Senescence Processes of Cut Rose Flowers

Kinetin delays the fading of cut rose (Rosa hyb. cv. Golden Wave) flower shoots exposed to water stress conditions. Using leafless flower shoots (i.e., a plant system devoid of stomates), we demonstrated that the main initial effect of kinetin was on increasing water uptake and petal growth. Later, kinetin slowed down processes associated with both senescence and stress (RNase activity and dry weight reduction), and maintained petal turgidity for an extended period.     

玫瑰切花保鲜剂配方研究

以蔗糖(S)、8-羟基喹啉(8-HQ)、柠檬酸(CA)为保鲜液的基本配方,分别加入CaCl2 、NaCl、Al2(SO4)3、CaCl2+KAl(SO4)2 组成四种保鲜液,进行玫瑰切花保鲜实验。对切花瓶插寿命、花径、水分平衡值、可溶性蛋白含量和还原糖含量进行分析。结果表明,各种配方保鲜液均能延长玫瑰切花的瓶插寿命、增大花径、改善切花水分代谢状况、降低切花蛋白质和还原糖的分解速度。其中,保鲜液2% S + 280 mg/L CA + 200 mg/L 8-HQ + 1% CaCl2的保鲜效果最好。     

Possible Roles of Methyl Glucoside andMyo-inositol in the Opening of Cut Rose Flowers

Methyl glucoside andmyo-inositol are present in all organs ofrose (Rosa hybridaL.). To investigate the possible role of thesecarbohydrates in the opening of cut roses, flowers with a 10,20 or 40-cm-long stem and a single flower bud (about 1.5 cmin diameter) were placed in water and flower opening and changesin sugar content in flowers and stems examined for 7 d. Thelonger the stem of the cut flower, the larger was the flowerdiameter. In stems, the concentration of carbohydrates, includingmethyl glucoside andmyo-inositol markedly decreased before floweropening. In petals, contents of glucose, methyl glucoside andmyo-inositolalso decreased before flower opening, but those of fructose,sucrose and xylose did not. When glucose and methyl glucosidewere added to the vase water (4%) flower opening was clearlypromoted; this was accompanied by an increase in methyl glucosideand fructose concentrations in petals. On the contrary,myo-inositolinhibited flower opening, and this was accompanied by an increaseinmyo-inositol and xylose concentrations in petals. These resultssuggest that methyl glucoside and/or its metabolites are transportedinto the petal cells, thereby lowering the osmotic water potentialand promoting flower opening.Myo-inositol is not readily metabolized,and exogenousmyo-inositol given at a high concentration mayact as an extracellular osmolyte, which inhibits water uptakeand flower opening.Copyright 1999 Annals of Botany Company Cut flowers, methyl glucoside,myo-inositol,Rosa hybrida,soluble carbohydrate.     

Hormonal Balance in Wheat Infected with Helminthosporium sativum

Using immunoenzyme assay, we studied the levels of phytohormones in resistant and susceptible varieties of wheat infected with Helminthosporium sativum. The infection of wheat with this pathogen leads to an increase in cytokinins in plants of the resistant variety in the presence of stable IAA/ABA ratio. The level of ABA increases in the infected plants of the susceptible variety. The role of hormones in the mechanisms of plant resistance to fungal infections is discussed.     

Role of Aminocyclopropane-1-carboxylic Acid (ACC) in Control of Ethylene Production in Fresh and Cold-stored Rose Flowers

The relationships between ethylene production, aminocyclopropane-1-carboxylicacid (ACC) content and ethylene-forming-enzyme (EFE) activityduring ageing and cold storage of rose flower petals (Rose hybridaL. cv. Gabriella) were investigated. During flower ageing at20 °C there was a climacteric rise in petal ethylene production,a parallel increase in ACC content, but a continuous decreasein EFE activity. Applied ACC increased petal ethylene productionc. 200-fold. During cold storage of flowers at 1 °C therewere parallel increases in petal ethylene production and ACCcontent, to levels greater than those reached in fresh flowersheld at 20 °C. EFE activity decreased during storage. Immediatelyafter cold-stored flowers were transferred to 20 °C ethyleneproduction and ACC levels were c. four times greater than infreshly cut flowers. These levels increased to maximum valuesof two to four times the maximum values reached during ageingof fresh, unstored, flowers. It was concluded that in rose petalsethylene synthesis is probably regulated by ACC levels and thatcold storage stimulates ethylene synthesis because it increasesthe levels of ACC in the petals. Key words: Rose flower, senescence, ethylene     

植酸对月季切花瓶插寿命的影响

用0.13％和0.013％植酸对月季切花进行处理,探讨了植酸对月季切花瓶插寿命及衰老过程中一些生理生化指标的影响.结果表明,013％和0.013％植酸处理的切花,瓶插寿命分别延长了2.3 d和1.4d.植酸处理抑制了O-2含量的增加和POD活性的提高,从而减轻了O-2对植物细胞的伤害即抑制丙二醛含量增加,同时抑制了可溶...     

Hormonal Control of the Teleost Ovary

The endocrine basis of gonadal development, reproductive processes,and many peculiarities related to reproduction in females ofthe highly diveisified teleosts can not yet be described satisfactorily.Although estrogens have been extracted from ovaries and peripheralblood of several species and various steroids were found tobe produced by ovarian tissue in vitro, there is an almost completelack of knowledge about their physiological role. It is beyond any doubt that hormones of the pituitary have amarked influence on ovarian maturation but many problems awaitfurther clarification. It is not yet clear whether gonadotropichormones might have a direct influence on certain traits ofbehavior in females. Biochemical work and a large number ofhistophysiological studies are at variance with regard to thequestion whether one or two gonadotropic hormones exist in teleosts.Technical difficulties (eg., shortage of hormonal material fromvarious sources, species specificity of gonadotropic hormone(s), widely scattered data from a large array of species withconsiderable differences in reproductive biology) hamper comparativeanalysis, Investigations on the hypothalamic control of endocrineevents are just in their beginning. The unique occurrence ofambisexual species in teleosts raises many questions which remainto be solved.     

Hormonal Control of Meiosis in Starfishes

Development of starfish oocytes is blocked at the prophase stage of the first meiotic division. The resumption of meiotic divisions occurs under the effect of the maturation hormone 1-methyladenine (1-MeA), which binds to a specific receptor of the oocyte cell surface. New data in the literature on endocellular signal mechanisms taking part in conduction of the regulatory signal modulated by 1-MeA are adduced in the review. Data on the properties of the 1-MeA receptor are presented and mechanisms of biosynthesis of 1-MeA are considered. The main focus is on processes occurring in the oocyte during the first minutes after the impact of the hormone, before the destruction of the germinal vesicle. A hypothetical pattern of transduction of the hormonal signal is proposed.     

Hormonal Changes Associated with Vegetative Malformation of Mango (Mangifera indica L.)

Malformed seedlings of mango showed lower mean content of indole-3-acetic acid, gibberellic acid and a higher mean content of zeatin, abscisic acid and ethylene than healthy seedlings.     

生长素与乙烯对兰花授粉后花发育的调节作用(英文)

以朵丽蝶兰为材料,对乙烯和生长素调节的授粉后花的发育进行了研究。实验结果显示,切花和植株上的花授粉后,乙烯的产生和花的发育无明显差异;花瓣的衰老、子房发育、花粉萌发和花粉管的伸长受乙烯调节;与切花相比,植株上花的子房内无ＡＣＣ合酶和ＡＣＣ 氧化酶ｍＲＮＡ 的积累。用生长素运输抑制剂２ ［（１ｎａｐｈｔｈａｌｅｎｙｌａｍｉｎｏ）ｃａｒｂｏｎｙｌ］ ｂｅｎｚｏｉｃａｃｉｄ（ＮＰＡ） 处理柱头,授粉诱导的子房发育在很大程度上受到抑制, 表明授粉后子房的发育需要转运来的生长素。     

The Hormonal Control of the Amphibian Ovary

The ultimate control of amphibian gonadal function rests withenvironmen tal factors mediated through the hypothalamus. Itappears that control of ovarian growth resides in the infundibularregion and ovulation in the preoptic area. For normal temporalrelationships between oocyte growth and ovulation to occur,an intact hypothalamo-pituitary complex is necessary. It isuncertain whether the several types of pituitary basophils considered,histologically as gonadotropin producing cells are in fact producingseparate LH and FSH like hormones. Perhaps the concensus indicatesa single hormone has both vitellogenic and ovulatory functions.This hormone stimulates estrogen synthesis and secretion bythe ovarian follicle cells, and this steroid causes oviductgrowth and the hepatic biosynthesis of vitellogenin, the majoryolk platelet precursor. Uptake of this lipoprotein from thecirculation and its conversion to the components of the plateletis mediated by the gonadotropin, the presence of which resultsin the establishment of a rapid micropinocytotic process atthe level of the oocyte surface and of a mechanism for crystallizationof the yolk. A sudden surge of pituitary hormone, when presentedto fully grown oocytes leads to their maturation and ovulation,and to oviducal jelly release in some species. The active hormoneis progestin in nature, again produced by the follicle cells. In this review the known factors involved in the hypothalamohypophysio ovarian axis are discussed together with some considerationof outstanding problemsand the possible relevance ot ovipantvand ovovivipanty in amphibians to the ovarian control foundin viviparous species.     

Hormonal Control of Tumor Formation in Radish

The role of phytohormones in genetic tumor formation on radish crop-roots was investigated using the collection of inbred Raphanus sativus lines as a model system. The genetic analysis showed that the trait <<tumor formation>> was recessive and monogenic in some crossings. The spectrum of main phytohormones in tumor and non-tumor radish lines has shown that at the initiation of tumor formation (30 days old plants) the amounts of main cytokinins in the lower part of plants from the tumor line were dramatically increased. The transformation of the non-tumor line by the ipt gene of Agrobacterium tumefaciens resulted in tumor formation in plants of the T₁ progeny. We propose that increasing the cytokinin/auxin ratio may lead to tumor formation on radish crop roots.     

Hormonal Control of Molting in Decapod Crustacea

The involvement of the molting hormone, 20-hydroxyecdysone,in the mediation of molting in decapod crustaceans is brieflyreviewed. Aspects of the secretion and metabolism of its precursor,ecdysone, are discussed. Experiments are described that demonstratethe presence of a molt-inhibiting hormone (MIH) in the sinusglands of juvenile lobsters (Homarus americanus). Assays forMIH include measurement of the molt interval and radioimmunoassayof circulating titers of ecdysteroids in eyestalk-ablated lobsters.This latter assay indicates that sinus gland extracts significantlydecrease the concentration of circulating ecdysteroids 24 hrafter injection. Data are also presented on the circulatingtiters of ecdysteroids during multiple molt cycles of lobstersfollowing eyestalk ablation. These data indicate that theremust be another factor that ultimately regulates the circulatinglevels of the molting hormone.     

Combined Effects of Abscisic Acid and Sucrose on Growth and Senescence of Rose Flowers

The effects of sucrose and abscisic acid (ABA) and their interaction on development and senescence of petals were studied with leafless roses cultivar Super Star. Sucrose and ABA had opposing effects on the cut flowers. Sucrose retarded and ABA promoted processes associated with senescence: wilting, increase in pH, “blueing” and decrease in protein content of petals. These opposing effects are mutually antagonized when both chemicals are applied. ABA applied to flowers cut at the bud stage, promoted the rate of petal growth (but not their final size), increased respiration and caused a decrease in sucrose and an increase in level of reducing sugars. It is suggested that one way by which ABA accelerates senescence of cut roses is by promoting petal growth and respiration, thus decreasing the carbohydrate level in the petals and triggering the chain of metabolic processes leading to aging.     

The Involvement of Water Stress and Ethylene in Senescence of Cut Carnation Flowers

Exposing cut carnation (Dianthus caryophyllus, cv. White Sim)to short term (12 h) water stress resulted in a marked increasein the water saturation deficit (WSD) of the petals. Full recoveryoccurred upon transfer of the flowers to water in humid conditions(r.h. 85%). However, an increase in aminocyclopropane carboxylicacid (ACC) content occurred immediately upon stress. An associatedrise in ethylene production following transfer to humid conditionswas observed earlier than in the control. Exogenous ethylene,applied alone or in combination with water stress, increasedthe WSD of the petals. Continuous treatment of cut flowers with amino-oxyacetic acid(AOA), a known inhibitor of ACC synthesis, suppressed ethyleneproduction, delayed the rise in WSD which accompanied developmentand senescence and hence delayed wilting. Similar results wereobtained with short term (2 h) treatment with AOA prior to stressingthe flowers. Short term AOA treatment partially inhibited therise in WSD during the stress period. On the basis of our findings, in particular that no rise inethylene production occurred during water stress, it is suggestedthat the effect of water stress is not directly mediated byethylene. The possible modulatory effect of water stress andAOA on certain characteristics of the petal cell membrane isdiscussed.