FLOWER CULTURE OF A MALE STERILE STAMENLESS-2 MUTANT OF TOMATO (LYCOPERSICON ESCULENTUM)

Young floral buds of a male sterile stamenless-2 (sl-2/sl-2) mutant of tomato were cultured, at the sepal primordia stage, in a liquid Murashige and Skoog medium containing either benzylaminopurine (BAP) or gibberellic acid (GA₃) or both. In the basal medium (BM), the buds initiated petal and stamen primordia only and they showed limited development. In buds grown in BM supplemented with 10^–6 M BAP, all types of organ primordia were initiated but the petals remained small and the stamens and carpels were immature. Well-developed flowers with a normal complement of floral organs were, however, produced in a medium containing both BAP (10^–6 M) and GA₃ (10^–7 M to 10^–5 M). The development of stamens was variable and ranged from the complete absence of microsporogenesis to the formation of abnormal pollen. Gynoecium development was normal and ovules with megaspores were produced in the ovary. The results show that male sterility in the sl-2/sl-2 mutant can be expressed in vitro and that GA₃ is essential for the in vitro growth and development of all the floral organs of this mutant.     

FURTHER OBSERVATIONS ON THE DIFFERENTIAL SENSITIVITIES TO PLANT GROWTH REGULATORS BY CULTURED “SINGLE” AND “DOUBLE” FLOWER BUDS OF NIGELLA DAMASCENA L. (RANUNCULACEAE)

In Nigella damascena, where “doubleness” behaves as a single gene character, recessive to the normal wild “single” form, we detected a number of differential responses of cultured floral apices of the two forms to plant growth regulators. “Single” buds initiated all organ types on a defined medium lacking any plant growth regulators. “Double” buds, however, required either kinetin or GA₃ for the development of a normal organ complement. Kinetin enhanced the growth and development of buds of both genotypes, whereas GA₃, at all concentrations, specifically inhibited the initiation and growth of stamens and nectaries in “single” buds. No combination of IAA or kinetin overcame this inhibition of “single” buds by GA₃. In the presence of both IAA and GA₃, “single” buds, following the initiation of normal carpels, initiated a few abnormal carpelloid structures from regions which had failed to produce stamens and nectaries. These observations, coupled with other studies including those on the endogenous levels of gibberellin in the two genotypes, suggest that “doubleness” correlates strongly with a modification of gibberellin metabolism. The causal connection between the two phenomena is as yet to be discovered.     

THE EFFECTS OF GIBBERELLIC ACID AND A GROWTH RETARDANT ON OVULE FORMATION AND GROWTH OF EXCISED PISTILS OF NIGELLA RANUNCULACEAE

The effects of gibberellic acid (GA₃) and the growth retardant AMO-1618 on ovule formation in excised pistils of Nigella sativa L. were studied by sterile culture techniques. Gibberellic acid promoted pistil growth and inhibited ovule formation. The role of endogenous gibberellins in ovule formation and pistil growth was investigated by adding AMO to the basal medium. Both pistil lengths and ovule formation were reduced significantly with increasing concentrations of AMO. The addition of low concentrations of GA₃ to the medium restored pistil growth but did not reverse the inhibitory effect of AMO on ovule formation. The addition of kinetin or indoleacetic acid (IAA) to the medium containing AMO had no effect on pistil lengths. However, with the addition of 10⁻⁷ m kinetin, the number of ovules in pistils was increased but not to the levels found in pistils grown in the absence of AMO.     

Experimental control of floral reversion in isolated shoot apices of the long-day plant Silene coeli-rosa

The fate of shoot meristems of the long day (LD) plant Silene coeli-rosa in culture was examined (complete, reverted or arrested flowers) to establish whether these different patterns were related to a particular stage of morphogenesis and the extent to which the fate of the pattern was regulated by either added plant growth regulators (PGRs) or changing the carbohydrate source in the medium. In particular, the frequency of reversion was measured to test the stability of the determined state for each whorl. The plants were given various inductive treatments (4–7 LD, 7 LD + 1 to 3 SD) and the apices were explained onto Murashige-Skoog medium supplemented with 3% sucrose (controls) ± IAA, ± kinetin, ± GA₃ or onto the basal medium containing 1 or 3% sucrose, glucose or fructose or 7% sucrose. The apices were examined 12 weeks later. When the data were pooled from all inductive treatments, IAA resulted in more reversions, GA₃ caused more arrested flowers while kinetin hardly affected the pattern of meristem fate compared with the controls. However, each PGR treatment did not perturb the pattern of organ formation for those apices that formed either arrested or complete flowers. The time for determination (days) of the earlier formed whorls (determination times for the controls in brackets): sepals (2), stamens 1–5 (3) and petals (3), was shortened by about a day in all PGR treatments whereas the corresponding times for the later formed whorls: stamens 6–10 (4) and carpels (4), were either lengthened to 5 days or unaffected. The response of the apices to the various sugars was simply a reflection of concentration. Hence, more complete flowers formed at 7 or 3% and more flowers were arrested at 1 % regardless of the sugar moiety. However, the frequency of reversion was similar on each of the media. Pooling all data from all treatments enabled a statistical analysis of the pattern of reversion and the pattern of arrest. Reversion was more common from apices which exhibited the later-formed whorls (stamens 6–10 and carpels) than from the earlier whorls. Moreover, the stronger the inductive treatment the less frequent was reversion. The most common stage of arrest was at the stamen 6–10 whorl and this was particularly so for the GA₃ treatment. The data indicated that reversion could occur from any whorl, which suggests that determination of each whorl is independent of the next. This conclusion is underlined by the more frequent occurrence of reversion from the carpel whorl. However, the longer the inductive treatment the less likelihood of reversion; this suggests that in Silene, the floral stimulus is required continuously to stabilise the determined state of each whorl and to ensure smooth completion of floral morphogenesis.     

Morphogenic Potentialities of Flower Buds of Kalanchoe pinnata Pers. grown in vitro

Excised flower buds of Kalanchoe pinnata Pers. representingtwo early stages of development (designated sets I and II),were cultured on modified White's medium (WB). They failed toattain full development on WB or on WB containing any of thefollowing supplements: indole-3yl-acetic acid (IAA), 2,4-dichlorophenoxyaceticacid (2,4-D), naphthaleneacetic acid (NAA), kinetin, or coconutmilk (CM). A slight stimulation of the growth of corolla wascaused by kinetin (10 ppm). IAA (I ppm) and NAA (I ppm) inducedrooting from the cut end of the pedicel and from the proliferatedtorus tissue situated between the sepals and petals. 2,4-D (Ippm) either singly or in concert with CM (10 per cent) stimulatedthe formation of shoot buds and root growth. Addition of kinetin(I and 10 ppm) to WB favoured shoot formation, but suppressedrooting. Flower buds of set II developed shoot buds more readilythan those of set I. Thus, the primordia floral organs presentin the immature buds lose their ability for normal morphogenesisunder culture conditions. Buds destined to form flowers canbe made to revert to vegetative growth.     

Effect of Gibberellic Acid, 2,3,5-Triiodobenzoic Acid and Indole Acetic Acid on Growth and Development of Impatiens balsamina during Different Photoperiods

This paper deals with the effect of 100 mg/1 each of GA₃ TIBA and IAA singly and in combination with each other on stem elongation, development of lateral branches and floral bud initiation in Impatiens balsamina plants exposed to 8-, 16- and 24-h photoperiods. GA₃ enhances stem elongation, the enhancing effect decreasing with IAA as well as with TIBA during 8-h but increasing during 16- and 24-h photoperiods. It decreases the number of lateral branches, the decrease being greatest during 16-, less during 8- and the least during 24-h photoperiods. The time taken for floral buds to initiate with and length of branches during 16-h photoperiods. During 8-h photoperiods, IAA delays the initiation of floral buds, while GA₃ hastens it when used together with TIBA or IAA or both. GA₃ increases the number of floral buds on the main axis but decreases it on lateral branches, while TIBA decreases the number on the main axis but increases it on lateral branches. IAA reduces the number of floral buds on the main axis only when used alone, but on both the main axis as well as on lateral branches when used together with GA₃ and TIBA. Floral buds were not produced on lateral branches when plants were treated with GA₃, TIBA and IAA all together. GA₃ and TIBA induced floral buds even under non-inductive photoperiods, the number of buds and reproductive nodes being less in TIBA- than in GA₃-treated plants during 24-h photoperiods. The time taken for floral buds to initiate with GA₃ and TIBA during noninductive photoperiods is much longer than that during 8-h inductive photoperiods with or without GA₃ or TIBA application. IAA completely inhibits the GA₃- and TIBA-caused induction during 24-h, but only delays it and reduces the number of reproductive nodes and floral buds during 16-h photoperiods.     

REGULATION OF GROWTH AND CELLULAR DIFFERENTIATION IN DEVELOPING AVENA INTERNODES BY GIBBERELLIC ACID AND INDOLE-3-ACETIC ACID

Auxin (IAA) at physiological concentrations causes significant reduction of GA₃-promoted growth in excised Avena stem segments. IAA is thus considered to be a gibberellin antagonist in this system. It was found to act non-competitively in repressing GA₃-augmented growth in these segments. In intercalary meristem cells at the base of the elongating internode, GA₃ blocks cell division activity and causes a marked increase in cell lengthening. IAA substantially promotes lateral expansion in comparable intercalary meristem cells, particularly in the vicinity of vascular bundles underlying the epidermis. It also alters the plane of cell division in differentiating stomata. IAA at high concentrations (10⁻³, 10⁻⁴ m ), in combination with GA₃, overrides the effects of GA₃ on cell lengthening, while with low concentrations of IAA (10⁻⁹, 10⁻¹⁰m ), the effects of GA₃ are clearly dominant. At intermediate concentrations of IAA (10⁻⁶, 10⁻⁷m ), in the presence of GA₃, the effects of this treatment on cell differentiation closely parallel the pattern of differentiation in untreated tissue. It is postulated that a lateral gradient of auxin and gibberellin could control cell expansion in long epidermal cells during intercalary growth of the internode.     

HORMONAL REGULATION OF EPIPHYLLOUS BUD RELEASE AND DEVELOPMENT IN BRYOPHYLLUM CALYCINUM

The effects of various concentrations of several auxins and cytokinins separately and in combination on epiphyllous budding of Bryophyllum calycinum were investigated, using a marginal leaf strip method. The number of buds released per leaf in 10⁻⁶ m benzyladenine (BA) was 2.8 times greater than those in water, and 1.6 times greater in 10⁻⁵ m isopentyladenine (IPA). BA, IPA and kinetin were antagonistic to indoleacetic acid (IAA) or naphthaleneacetic acid (NAA) when used in combination treatments. The IAA oxidase co-factor p-coumaric acid (PCA) increased the number of epiphyllous buds to twice that of the water controls. This stimulatory effect of PCA on bud release suggests that an increase in IAA oxidase activity may be one of the significant changes that precedes the release of epiphyllous buds.     

Developmental study on the inflorescence and flower of Caldesia grandis Samuel (Alismataceae)

The inflorescence and floral development of Caldesia grandis Samuel is reported for the first time in this paper. The basic units of the large cymo‐thyrsus inflorescence are short panicles that are arranged in a pseudowhorl. Each panicle gives rise spirally to three bract primordia also arranged in a pseudowhorl. The branch primordia arise at the axils of the bracts. Each panicle produces spirally three bract primordia with triradiate symmetry (or in a pseudowhorl) and three floral primordia in the axils of the bract primordia. The apex of the panicle becomes a terminal floral primordium after the initiations of lateral bract primordia and floral primordia. Three sepal primordia are initiated approximately in a single whorl from the floral primordium. Three petal primordia are initiated alternate to the sepal primordia, but their subsequent development is much delayed. The first six stamen primordia are initiated as three pairs in a single whorl and each pair appears to be antipetalous as in other genera of the Alismataceae. The stamen primordia of the second whorl are initiated trimerously and opposite to the petals. Usually, 9–12 stamens are initiated in a flower. There is successive transition between the initiation of stamen and carpel primordia. The six first‐initiated carpel primordia rise simultaneously in a whorl and alternate with the trimerous stamens, but the succeeding ones are initiated in irregular spirals, and there are 15–21 carpels developed in a flower. Petals begin to enlarge and expand when anthers of stamens have differentiated microsporangia. Such features do not occur in C. parnassifolia. In the latter, six stamen primordia are initiated in two whorls of three, carpel primordia are initiated in 1–3 whorls, and there is no delay in the development of petals. C. grandis is thus considered more primitive and C. parnassifolia more derived. C. grandis shares more similarities in features of floral development with Alsma, Echinodorus, Luronium and Sagittaria. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 39–47.     

商陆属植物的花器官发生

为进一步研究商陆科的系统位置提供花器官发生和发育的证据,在扫描电子显微镜下观察了商陆Phytolacca acinosa、多雄蕊商陆P. polyandra和垂序商陆P. americana的花器官发生.结果表明: 商陆属植物花被的发生均为2/5型螺旋发生.在同一个种不同的花蕾中,花被的发生有两种顺序:逆时针方向和顺时针方向.远轴侧非正中位的1枚先发生.雄蕊发生于环状分生组织.在单轮雄蕊的种中8-10枚雄蕊为近同时发生;两轮雄蕊的种8枚内轮雄蕊先发生,6-8枚外轮雄蕊随后发生,内轮雄蕊为同时发生,外轮雄蕊发生次序不规则.心皮原基也发生于环状分生组织,8-10枚心皮原基为同时发生.在后来的发育过程中,商陆的心皮发育成近离生心皮雌蕊;其他2种心皮侧壁联合发育成合生心皮雌蕊.对商陆属植物花器官发生的类型及发育形态学做了分析,结果支持商陆科在石竹目系统发育中处于原始地位的观点.     

Role of mineral nutrients and growth regulators in the apical dominance in Solanum sisymbrifolium

Summary The lower axillary buds of intact plants of Solanum sisymbrifolium are released from complete inhibition by supplying high doses of potassium to the soil while complete apical dominance is shown by plants grown at low, but not deficiency levels of K. Nitrate and phosphate supplied alone or together are ineffective but when either of them is supplied with K, the effect of the latter on the growth of axillary buds is somewhat enhanced. The buds thus released from inhibition elongate further only when supplied with gibberellin A₃ (GA₃). Indoleacetic acid (IAA) alone has a considerably weaker effect but when supplied with GA₃ the stimulatory effect is greater than is caused by the latter alone. The completely inhibited buds of low-K plants can be released from inhibition by supplying kinetin. In such buds IAA promotes further extension but GA₃ does not. The partially inhibited buds of the high-K plants, on the other hand, are not affected by exogenous kinetin.Dedicated to Professor H. D. Wulff on the occasion of his 60th birthday.     

DEVELOPMENT AND VASCULATURE OF THE FLOWERS OF LOPHOTOCARPUS CALYCINUS AND SAGITTARIA LATIFOLIA (ALISMACEAE)

The development of the bisexual flower of Lophotocarpus calycinus and of the unisexual flowers of Sagittaria latifolia has been observed. In all eases floral organs arise in acropetal succession. In L. calycinus, after initiation of the perianth, the first whorl of stamens to form consists of six stamens and is ordinarily followed by two alternating whorls of six stamens each. The very numerous carpels arc initiated spirally. In the male flower of S. latifolia the androecium develops in spiral order. A few rudimentary carpels appear near the floral apex after initiation of the stamens. There are no staminodia. The female flower has a similar developmental pattern to that of Lophotocarpus except that a prominent residual floral apex is left bare of carpels. The vascular system in all flowers is semiopen, with vascular bundles passing to the floral organs in a pattern unrelated to the relative positions of those organs. The androecia of these two taxa are similar to those of some Butomaceae and relationships based on ontogeny and morphology are suggested. The gynoecia are meristically less specialized but morphologically more specialized than the gynoecia of Butomaceae.     

Effect of growth regulators onVicia faba plants irrigated by sea water Leaf area,pigment content and photosynthetic activity

The antagonistic effects of some growth regulators [i.e. indol-3-yl-acetic acid (IAA), gibberellic acid (GA₃) or kinetin] on stress imposed by sea water on leaf area, pigment and photosynthetic activity in leaves of broad bean plants at different stages of development were investigated. Seed priming with GA₃ alleviated either partially or completely the effects induced by the two levels of sea water (10 and 25 %) used on leaf area at all experimental stages. However, IAA, GA₃ and kinetin inhibited leaf growth by themselves in almost all measurements. Seed pretreatment with kinetin alleviated the inhibition of pigment production in sea water-irrigated plants. Furthermore, GA₃ or kinetin nullified the deleterious effects imposed by irrigation with sea water particularly the high level (25 %) on photosynthetic¹⁴CO₂ fixation.     

青城细辛的花器官发生

利用扫描电镜观察了青城细辛(Asarum splendens)的花器官发生过程。青城细辛的花器官为轮状结构,向心发生,依次为两轮3基数的花被原基,两轮6基数的雄蕊原基和一轮6基数的心皮原基。两轮花被原基互生,只有外轮(先发生的一轮)花被原基完全发育,而内轮(后发生的一轮)花被原基在发育过程中逐渐退化。两轮雄蕊原基为离心发生:位于内侧的一轮雄蕊原基先发生,每两个原基正对第一轮发生的花被原基,外侧的一轮雄蕊原基后发生,与内轮雄蕊原基互生。心皮与内侧的一轮雄蕊互生。     

青城细辛的花器官发生

利用扫描电镜观察了青城细辛（Asarum splendens）的花器官发生过程。青城细辛的花器官为轮状结构,向心发生,依次为两轮3基数的花被原基,两轮6基数的雄蕊原基和一轮6基数的心皮原基。两轮花被原基互生,只有外轮（先发生的一轮）花被原基完全发育,而内轮（后发生的一轮）花被原基在发育过程中逐渐退化。两轮雄蕊原基为离心发生：位于内侧的一轮雄蕊原基先发生,每两个原基正对第一轮发生的花被原基,外侧的一轮雄蕊原基后发生,与内轮雄蕊原基互生。心皮与内侧的一轮雄蕊互生。     

IN VITRO CULTURE OF FLORAL BUDS OF AQUILEGIA

Tepfer, S. S., R. I. Greyson, W. R. Craig, and J. L. Hindman. (U. Oregon, Eugene.) In vitro culture of floral buds of Aquilegia. Amer. Jour. Bot. 50(10): 1035–1045. Illus. 1963.—Floral buds at various stages of development, from early stages before sepal initiation to late stages with young carpel primordia present, were grown in culture on various agar media. A basic medium containing White's minerals, Nitsch's trace elements, coconut milk, sucrose, and assorted water-soluble vitamins was developed for growth of the buds. The addition of indoleacetic acid, gibberellic acid, and kinetin to the basic medium extended the developmental limits of buds at nearly all stages and decidedly improved the continued development of carpels. On this medium buds produce all of their organ primordia, growing from early stages to about the size of flowers at anthesis, but will not develop unless the sepals are removed. This inhibiting effect of sepals is not understood at this time. Stamen development is consistently poor beyond the point of differentiation of anther and filament, even with the addition of hormones. The development of buds in culture is illustrated and compared with development in intact plants. With further improvement of the medium, it is hoped that these buds may be used for experiments testing theories of floral morphogenesis.     

In vitro propagation of shoot buds of Carica papaya L. (caricaceae) var. Honey Dew

Shoot buds from the saplings and the fruit bearing plants of Carica papaya L.. var. Honey Dew (papaya) initially treated with Gentamycin were cultured in modified MS media, each with a different hormonal combination, for the establishment of cultures and multiplication and rooting of plants. About 43% of explants from fruit bearing plants and 69% of those from saplings remained free of contamination and retained regeneration capacity when treated in 500 mg/l Gentamycin. For the establishment of the explants a medium containing 1 mg/l GA₃ and 2 mg/l kinetin was necessary. When established buds were transferred to medium containing 1 mg/l NAA and 3 mg/l kinetin, calli were initiated at cut ends of shoot buds; multiplication started on transfer to NAA (0.1 mg/l) and BAP (0.5 mg/l) medium. Cultures have been maintained for the last twenty months without any loss in multiplication rate. Rooting was induced in medium with reduced salt concentration containing 2 mg/l IBA. Shoot elongation was induced after prolonged culture in the same rooting medium.Abbreviations MS Murashige and Skoog, 1962 - SH Schenk and Hildebrandt, 1972 - GA₃ Gibberellic acid - Kn Kinetin - NAA Napthaleneacetic acid - BAP 6 -Benzylaminopurine - IBA Indole-3-butyric acid - IAA Indole-3-acetic acid     

Influence of some growth regulators on the sporelings of the marine alga Stoechospermum marginatum

Effects of gibberllic acid (GA₃), indole-3-acetic acid (IAA) and kinetin were studied on the thallus length growth of sporelings of Stoechospermum marginatum (C. Agardh) Kütz. (Dictyotales, Phaeophyceae), which were raised and cultured under laboratory conditions from the tetrasporophytes. IAA showed significant growth promotion over the controls at doses of 0.1 and 0.1 mg 1⁻¹. Kinetin was significantly effective at higher doses of 5.0 and 10.0 mg 1⁻¹, while GA₃ did not show any significant effect compared to the controls. These results are of applied value in raising the alga in mariculture.     

Floral morphogenesis and flowering in aseptic cultures ofBrowallia demissa L

Floral buds ofBrowallia demissa, at three stages of development, were cultured on Nitsch and Nitsch basal medium. The supplements used include IAA; several cytokinins— benzyladenine, kinetin and 6-benzyl-9 tetrahydropyran-adenine (SD 8339); gibberellic acid (GA₃); 2, 3, 5-triiodobenzoic acid (TIBA); arginine and cysteine. All three stages of floral buds failed to complete development. In some treatments stages II and III produced callus and/or roots from the morphological basal end. Cytokinins promoted bud formation whereas both IAA and GA₃ depressed bud formation The shoots differentiatedin vitro were capable of setting flowers, fruits and seeds in all the treatments. The seeds were viable. Comparative studies of development of flowersin vivo andin vitro were made. In some treatments the flowers exhibited abnormal corolla, and roecium and gynoecium. Factors affecting normal bud initiation, organization and development are discussed.     

宽叶泽苔草的花器官发生

通过扫描电镜观察了宽叶泽苔草Caldesia grandisSamuel.的花器官发生。宽叶泽苔草 的萼片3枚,逆时针螺旋向心发生 ;花瓣3枚,呈一轮近同时发生,未观察到花瓣_雄蕊复合原基;雄蕊、心皮原基皆轮状向心 发生,最先近同时发生的6枚原基全部发育成雄蕊,随后发生的6枚原基早期并无差别,在发 育过程中逐渐出现形态差异,直至其中1－4枚发育成心皮,其余的发育成雄蕊;而后的几轮 心皮原基,6枚一轮,陆续向心相间发生。本文揭示了3枚萼片螺旋状的发生方式,并推测这种螺旋方式是泽泻科植物进化过程中保留下来