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.     

Effect of gibberellins A3, A4+7 and A13 and of (−)-kaurene on flowering and extension growth of Impatiens balsamina under different photoperiods

Summary Gibberellins A₃, A₄₊₇ and A₁₃ and (–)-kaurene delay floral-bud initiation and flowering and decrease the number of floral-buds and flowers in Impatiens balsamina under 4-hr photoperiods. They do not have any marked effect under 8-hr photoperiods. Under 16- and 24-hr photoperiods they hasten floral-bud initiation and flowering and increase the number of flowers, the effect being greater under 16- than under 24-hr days and the order of effectiveness being GA₄₊₇>GA₃>GA₁₃>(–)-kaurene.While GA₃ and GA₄₊₇ promote extension growth, the effect being greater with the former, GA₁₃ and (–)-kaurene do not promote it under any photoperiod. The magnitude of stem elongation in different treatments prior to floral-bud initiation increases from 4- to 8-hr photoperiods but decreases under 16- and 24-hr periods, the effect being more under 24-hr although both 16-and 24-hr photoperiods are noninductive for flowering.     

The Effect of Gibberellic Acid and Guanosine Monophosphates on Extension Growth, Leaf Production and Flowering of Impatiens balsamina

Gibberellic acid (GA₃) increases the height of Impatiens balsamina under both 8- and 24-h photoperiods. The height also increases with all guanosine monophosphates (GMPs) under 8-h photoperiods but only with 5′-GMP under 24-h photoperiods. GA₃ as well as GMPs increase the number of leaves under 8-h but not under 24-h photoperiods. GA₃ as well as GMPs induce floral buds under strictly non-inductive photoperiods and increase the number of floral buds under 8-h photoperiods. The floral bud initiation occurs earlier when cGMP is used in combination with 100 mg/l GA₃.     

EFFECTS OF LEAF EXCISION ON FLOWERING OF XANTHIUM APICAL BUDS IN CULTURE UNDER INDUCTIVE AND NONINDUCTIVE PHOTOPERIODS

Apical buds of Xanthium were grown in aseptic culture under short-day cycles known to induce flowering in the intact plants or under “light-break” conditions known to prevent flowering. The total light provided in each 24-hr cycle was the same under the two photoperiods. Various numbers of leaves were excised from the apical buds. Excision of leaves did not change the response to photoperiod: even with all leaves excised the apical buds cultured under short-day conditions reached the same average floral stage as the control buds, and those under light-break conditions all remained vegetative. Fresh weight was not significantly changed by the excisions, either. However, excision of the young leaves resulted in an increase in the number of new leaves developed by the apical bud during the two-week culture period.     

Studies on the Transmission of Floral Effects of Photoperiod and Gibberellin from One Branch to the Other inImpatiens balsamina

In two branched plants ofImpatiens balsamina with intact apex and leaves floral buds are induced only in the branch which is either exposed to 8-h (inductive) photoperiods or receives GA₃ treatment if maintained under 24-h (non-inductive) photoperiods. GA₃ induces floral buds on the treated branch even if the leaves on that branch are removed, showing that while leaves are essential for photoperception, these are not neoessary for GA₃ to cause induction. The effect of the inductive photoperiods or GA₃ treatments to a branch is not transmitted to the other branch which is treated with water and is maintained under non-inductive photoperiods even when the latter is defoliated but is transmitted if the apioal or both the apical and axillary buds on the branch receiving inductive photoperiods or GA₃ treatment are excised. It, therefore, appears that the existence of strong sinks in the form of axillary and apical buds on the treated branch prevents the transmission of photoperiodic as well as GA₃ effects to the other branch in this plant.     

Effect of ínductive photoperiod and gibberellin treatment on peroxidase enzyme system in relation to floral induction inImpatiens balsamina L

Gibberellins A₃ and A₁₃ cause floral induction inImpatiens balsamina, a qualitative short day plant, under non-inductive 24-h photoperiods (continuous illumination). However, the influence of the two inductive factors,i.e. gibberellins and short days (8-h photoperiods) on the peroxidase enzyme system is different. The total peroxidase activity decreases under both inductive and non-inductive photoperiods, with or without gibberellin treatment. The electrophoretic pattern of isoperoxidases changes only in response to gibberellin treatment. Under 24-h photoperiods, treatment with gibberellins A₃ and A₁₃ causes the appearance in the stem of three additional isoenzymes of peroxidase (Rm 0.50, 0.71 and 0.76). These bands do not appear in the leaves, which are non-essential for gibberellin-caused floral induction in this plant. Under 8-h photoperiods also, gibberellins induce the appearance of new isoenzyme bandsi.e. two in the stem (Rm 0.50 and 0.76) and one in the leaves (Rm 0.05). These may be correlated with the synergistic increase in the number of floral buds in these plants in response to simultaneous exposure to two inductive factors.     

In vitro formation and development of floral buds on tobacco stem explants: effects of kinetin and other factors

Stem segments were excised from plants of Wisconsin 38 tobacco (Nicotiana tabacum L.) in three regions differing in their distance below the inflorescence. They were cultured in vitro in 8- or 16-hr days. After 8 weeks, floral and vegetative buds were counted, and extent of floral development was assessed. Kinetin at 10(-5)m inhibited formation and development of floral buds regardless of indoleacetic acid concentration. Supplied at this concentration with adequate auxin, kinetin stimulated vegetative bud formation and may have caused floral bud abortion. Indoleacetic acid (>/= 10(-6)m) inhibited vegetative and floral bud formation when supplied with low kinetin concentration (/= 10(-6)m), it inhibited floral bud formation and stimulated vegetative bud formation. More floral buds were formed in 16-hr days than in 8-hr days. Few formed on explants other than those derived from the region nearest the inflorescence regardless of other treatment.     

Photoperiod- and temperature-dependent induction of larval diapause in a multivoltine bruchid, Bruchidius dorsalis

The wild bruchid beetle, Bruchidius dorsalis Fahraeus (Coleoptera: Bruchidae), has a multivoltine life cycle and overwinters in several developmental stages in the middle part of Japan. We investigated the incidence of diapause under different conditions of photoperiod (from L8:D16 to L16:D8) and temperature (at 20 °C and 24 °C). Our experiments revealed the following results: (1) B. dorsalis entered diapause at the final (late fourth) instar larva under short photoperiods, (2) the larval diapause incidence was dependent on temperature (critical photoperiods were 12.5 h at 20 °C and 12 h at 24 °C), (3) some individuals did not enter diapause under short-photoperiod conditions at 24 °C, and (4) the sensitive stages to the photoperiod were from the late egg stage to the early first instar larva. Based on these results, we discuss not only the evolution of a complex overwintering strategy inB. dorsalis but also the domestication process of stored-bean pests.     

Induction of flowering ofImpatiens balsamina treated with gibberellic acid and resorcinol

Under strictly non-inductive photoperiods (24-h photoperiods) floral buds were initiated on plants receiving 25 treatments with Reso (resorcinol) or 8 treatments with GA₃ (gibberellic acid) or GA₃ + Reso, while water treated control plants did not flower at all. Although a single treatment of plants with GA₃ or GA₃ + Reso is not adequate to cause induction under LD conditions, its effect is added to the sub-threshold induction caused by one SD (short day: 8-h photoperiod) cycle. The initiation of floral buds was hastened with an increasing number of SD cycles accompanying respective number of treatments, the effect of GA₃ alone or together with Reso being more pronounced than that of Reso alone. GA₃ increased the number of floral buds more than Reso, the number being the highest in plants receiving the respective number of treatments with the combination GA₃ + Reso under both inductive as well as non-inductive photoperiods. Deceased.     

THE GROWTH OF A MIDWESTERN STRAIN OF SORGHUM HALEPENSE UNDER CONTROLLED CONDITIONS

Ingle , M., and B. J. Rogers . (Purdue U., Lafayette, Indiana.) The growth of a midwestern strain of Sorghum halepense under controlled conditions. Amer. Jour. Bot. 48(5): 392–396. Illus. 1961.—This grass, adapted to midwestern growing conditions, increased growth up to 32°C. under long-day conditions (16 hr.). In a 12-hr. photoperiod, growth increased up to 27°C; at 32°C. growth was reduced. Flowering usually occurred under photoperiods of 12 hr. or less, but this requirement was not absolute. Rhizome bud sprouting was found to be proportional to temperature. Regardless of the environmental conditions and variations tested, all buds on the rhizomes developed into aerial shoots and never into rhizomes.     

EFFECTS OF PHOTOPERIOD AND KIND OF SUPPLEMENTAL LIGHT ON GROWTH,FLOWERING, AND STEM FASCIATION OF CELOSIA

Piringer , A. A., and H. A. Borthwick . (U.S.D.A., Beltsville, Md.) Effects of photoperiod and kind of supplemental light on growth, flowering and stem fasciation of Celosia. Amer. Jour. Bot. 48(7): 588–592. Illus. 1961.—Four cultivars of Celosia argentea L. var. cristata were grown on photoperiods ranging from 8 hr to continuous light. Supplemental low-intensity incandescent light was used to extend 8 hr of natural light and provide the given photoperiod. In all cultivars, short main stems occurred on photoperiods of 12 or fewer hours and long main stems, due to more nodes, on photoperiods of 16 or more hours. Flowering was a nonobligate short-day response in all cultivars. Plants of certain cultivars tended to have shorter stems and flower later when 8 hr of fluorescent instead of incandescent light was used to provide the 16-hr photoperiod. In 3 of the cultivars studied, photoperiods of 16 or more hours induced marked stem fasciation.     

Effect of Gibberellic Acid and Phosfon on the Critical Dark Period Reqnirement for Flowering of Impatiens balsamina cv. Rose

The critical dark period requirement for flowering of Impatiens balsamina L. cv. Rose, an obligate short day plant, is about 8.5 hours. While GA₃ completely substituted for the dark period requirement, Phosfon prolonged it to 9.5 hours. GA₃ hastened and Phosfon delayed the initiation of floral buds under all photoperiods. Floral buds opened into flowers only during 8 and 14 hour photoperiods in control and Phosfon-treated plants but during all photoperiods in GA₃-treated ones. The delay in floral bud initiation and flowering was correlated with shifting up of the node bearing the first floral bud and flower respectively. While GA₃ increased the numher of floral buds and flowers in all photoperiods except 8-hour, Phosfon increased their number in the 14-hour photoperiod only. The number of flowering plants decreased with increasing photoperiod regardless of GA₃ and Phosfon application. The effect of Phosfon was completely or partially overcome, depending upon the photoperiod, by simultaneous application of GA₃.     

Daily changes in concentrations of prolactin in serum of prepubertal bulls exposed to short- or long-day photoperiods

Early temporal changes in concentrations of prolactin (PRL) in serum after a sudden change in photoperiod and daily responsiveness to PRL-releasing and inhibiting factors were investigated in prepubertal Holstein bull calves exposed to different photoperiods. In calves switched from 8-hr light: 16-hr dark to 16-hr light:8-hr dark, there was no observable change in the daily pattern of serum concentrations of PRL after 1, 2, or 4 days. On the other hand, in animals switched from 16-hr light:8-hr dark to 8-hr light:16-hr dark, there was a consistent increase in serum PRL from 33.4 ng/ml on Day 0 to maximum values of 57.3, 62.7, and 78.9 ng/ml between 14 and 18 hr after onset of light on Days 1, 2, and 4, respectively. Thus, absence of light allowed expression of a daily rhythm in serum concentrations of PRL that persisted for at least 4 days after the photoperiod switch. There were no differences in L-dopa inhibition of PRL release in animals exposed to 16-hr light:8-hr dark at 3 or 15 hr after onset of light. However, thyrotropin-releasing hormone-induced release of PRL was greater 3 hr after onset of light (11 hr after onset of dark) compared with release at 9, 15, and 21 hr after onset of light in animals exposed to 16-hr light:8-hr dark, but not in bulls exposed to 8-hr light:16-hr dark. The results provide evidence that the cue for the putative photosensitive period of PRL secretion in cattle may be more closely associated with onset of dark, not onset of light.     

Nitric oxide fumigation for control of navel orangeworm,Amyelois transitella,on walnut

The navel orangeworm (NOW), Amyelois transitella (Walker), is a major post-harvest pest of tree nuts including walnut, almonds and pistachios. Nitric oxide (NO) was recently discovered to be a potential fumigant under ultralow oxygen conditions for post-harvest pest control. In this study, NO fumigation was evaluated for efficacy against eggs, larvae and pupae of NOW. NO fumigation was found to be similarly effective against NOW on artificial diet and in infested walnuts. Fumigations of 4, 8 and 16 hr with 2.0, 1.0 and 0.5% NO, respectively, achieved complete control of small and large larvae in artificial diet. Complete control of pupae on artificial diet was achieved in 8, 16 and 24 hr fumigations with 2.0, 1.0 and 0.5% NO, respectively. For NOW in infested walnuts, complete control was achieved in 6, 8 and 16 hr fumigations with 1.5, 1.0 and 0.5% NO, respectively, for small larvae; in 4-, 8- and 24-hr fumigations with 2.0, 1.0 and 0.5% NO, respectively, for large larvae; and in 8-, 16- and 24-hr fumigations with 2.0, 1.0 and 0.5% NO, respectively, for pupae. Eggs were more tolerant to NO fumigation than larvae and pupae, and complete control of NOW eggs was achieved in 8- and 16-hr fumigation with 3.0 and 2.0% NO, respectively. This study demonstrated the efficacy of NO fumigation against NOW on walnut and its potential as an alternative post-harvest treatment for the pest.     

光周期对菊花花芽分化及其叶片和芽内源多胺含量的影响

以切花菊品种神马为材料,研究不同光周期(16h昼/8h夜;12h昼/12h夜;8h昼/16h夜)对菊花花芽分化过程中叶片和芽内腐胺(Put)、亚精胺(Spd)和精胺(Spm)含量的影响.结果显示:(1)16h/8h处理植株始终没有花芽分化,8h/16h处理的花芽分化开始和完成分别在处理后第13.9天和第23.1天出现,比12h/12h处理的分别提前1.7d和2.8d.(2)16h/8h处理叶片和芽中Put、Spd和Spm含量始终都没有明显变化,而8h/16h和12h/12h处理的叶片和芽中Put、Spd、Spm含量都比16h/8h处理的明显增加,而且8h/16h和12h/12h处理的叶片Put和Spd含量在处理第10天和第20天时出现2个高峰,芽中Put和Spd含量在处理第15天时出现一个高峰;另外,8h/16h处理的叶片和芽中Put、Spd含量比12h/12h处理的有所增加,但差异不显著.结果表明,菊花神马是质型短日照植物,短日照可诱导神马叶片和芽内合成多胺,而且日照时数越短,越有利于叶片和芽内Put、Spd、Spm的积累和促进花芽分化.     

Dna Synthetic Activity in Tumor-Bearing Mice

The rate of DNA synthesis in normal tissues exhibits circadian rhythmicity. However, there have been conflicting reports of the effects of tumor burden on the circadian rhythm of DNA synthesis in non-cancer tissues. We have developed a mouse colon cancer (MC-26) that exhibits different growth under different photoperiods. The purpose of this study was to analyze DNA synthetic activity in tissues removed from tumor-bearing and tumor-free mice maintained under two different photoperiods. Two groups each of approximately 80 male Balb/c mice were acclimated to one of two light-dark cycles, 12L:12D or 6L:18D. Half of each group were injected with 5.0 × 104 MC-26 cells. Twenty-two days later, all mice were killed in subgroups at 4-6 hr intervals over one 24-hr period. Colons and tumors were removed for measurement of DNA synthesis. Results were analyzed by means of one-way analysis of variance (ANO VA) in order to determine whether DNA synthesis varied significantly within groups over the 24-hr period. The DNA synthetic activity, as measured by uptake of tritiated thymidine, exhibited significant temporal variation in the colons of control (tumor-free) mice under both the 12L:12D and 6L:18D photoperiods. The colons of tumor-bearing mice failed to exhibit a fluctuation under a 12L:12D photoperiod but did show a significant 24-hr rhythm under the 6L:18D photoperiod. The subcutaneously growing cancers did not exhibit a circadian variation in DNA synthetic activity under either photoperiod. Both photoperiod and the presence of cancer appear to affect the DNA synthetic activity observed in mice bearing the MC-26 colon cancer.     

Photoperiod and Temperature Interactions in Growth and Flowering of Strawberry

Growth and flowering of strawberry cultivars were studied in controlled environments. Early cultivars adapted to marginal growing areas in Scandinavia initiated flower buds in all photoperiods including continuous light at temperatures of 12 and 18°C. At 24°C they remained vegetative in photoperiods above 14 or 16 h. The later cultivars ‘Senga Sengana’ and ‘Abundance’ did not initiate flower buds in 24-h photoperiods at any of these temperatures. Their critical photoperiod changed from above 16 h at 12°C to about 14 and 13 h at 18 and 24°C, respectively. It is concluded that at high latitudes temperature is as important as photoperiod in controlling flowering in the strawberry. Stolon formation, petiole elongation, and leaf area growth were stimulated by high temperature and long days, usually with optima at 16 h and 18°C for petiole elongation and 16 h and 24°C for stolon formation. Although growth and flowering responses in general were opposite, the results indicate that they are to some extent independent. The photoperiodic growth responses were mainly of morphogenetic nature. Dry weight of stem and leaves was little influenced by photoperiod when the irradiance was kept constant.     

INDUCED DIFFERENTIATION OF GERANIUM PLANTS FROM UNDIFFERENTIATED CALLUS IN VITRO

Geranium callus produced from explants of stem tip, internode pith with vascular tissue on synthetic media with or without coconut milk and 2,4-dichlorophenoxyacetic acid grew well for many generations, but only tracheids were induced in them. If callus produced on these media was subcultured immediately on Murashige and Skoog medium with 0.1 mg/liter/α-naphthalene acetic acid (NAA) and 10.0 mg/liter kinetin (K) and incubated at 16/8-hr light/dark cycle, shoots were induced in 8-10 weeks and roots in another 8-10 weeks. Callus produced on the MS medium with the same supplements of NAA and K, subcultured on the same medium and incubated in 16/8-hr light/dark cycle, produced shoots in 6-8 weeks. However, on callus subcultured more than three times, shoots differentiated with greater difficulty and none differentiated after six subcultures. Some abnormal shoot-like structures were also produced, the cells of which showed virus-like inclusion bodies. Requirements of the different varieties for differentiating organs differed. Among 12/12-, 15/9-, 16/8-, and 20/4-hr light/dark photoperiods that induced differentiation, 15/9- and 16/8-hr were more effective than the others. Continuous illumination did not induce differentiation. Differentiated shoots formed roots more readily on a medium with reversed proportions of auxin and kinetin. On agar roots were devoid of root hairs. Root hairs were formed when the shoots and plantlets were cultured on filter-paper bridges. Many “mother” stock plants were produced. These are being studied for their growth qualities and for possible viruses and other pathogens.     

ONTOGENY AND CORRELATIVE RELATIONSHIPS OF THE PRIMARY THICKENING MERISTEM IN FOUR-O'CLOCK PLANTS (NYCTAGINACEAE) MAINTAINED UNDER LONG AND SHORT PHOTOPERIODS

The developmental anatomy of Mirabilis jalapa was investigated during the first 90 days of growth. The primary thickening meristem (PTM) initially differentiates in the pericycle at the top of the cotyledonary node 18 days after germination, then basipetally in the pericycle through the hypocotyl. The PTM differentiates acropetally into the stem and in the pericycle of the primaiy root, commencing 22 days after germination. Endodermis is easily identifiable in hypocotyls as well as in primary roots because of Casparian thickenings in its cells. It has not been definitely identified in stems. There are three rings of primary vascular bundles in the stem. The PTM differentiates as segments of cambium in a layer of cells (probably in the pericycle) on an arc between vascular bundles of the outer bundle ring. Later, arcs of PTM differentiate externally to the phloem of each bundle. Each arc forms a connection between original segments of PTM lying on either side of each vascular bundle. Thus, the PTM becomes a continuous cylinder. The PTM differentiates in the pericycle outside vascular tissue in the hypocotyl and root. Differentiation of the PTM and the mode of secondary thickening is similar in plants exposed to short (8-hr) and to long (18-hr) photoperiods, but some differences were observed. The PTM differentiates closer to the stem apex in all plants over 18 clays of age growing vegetatively under long photoperiods. That is, the diffuse lateral meristem, in whose cells the PTM differentiates in young intemodes, is shorter in nearly all investigated plants growing in long photoperiods. The hypocotyl and base of the primary root of 40-day-old plants in short photoperiods were more enlarged than those of the same age plants in long photoperiods; but, at the end of 64 days, the hypocotyl and primaiy root base were larger in plants growing under short photoperiods. Thirty-four days after seed germination, flower initiation occurs in plants exposed to short photoperiods. One hundred fifty days after seed germination, flowers differentiate on plants exposed to long photoperiods.     

Effect of photoperiod on growth and gonadal development of juvenile Topmouth Gudgeon Pseudorasbora parva

In this study, we investigated the effect of photoperiod on growth and gonadal development of juvenile topmouth gudgeon, Pseudorasbora parva. Seven different photoperiods (light:dark, L:D) were tested: 0L:24D, 4L:20D, 8L:16D, 12L:12D, 16L:8D, 20L:4D and 24L:0D, from November to January. Throughout the study, light intensity was kept at 400 lx on the water surface, and the fish were fed a commercial diet twice a day. Weight gain, feed intake, specific growth rate, and feed conversion efficiency were significantly higher under the constant–long day photoperiods (24L:0D, 20L:4D and 16L:8D) than those under the short–no day photoperiods (12L:12D, 8L:16D, 4L:20D, 0L:24D) (p?<?0.05). The highest mean female gonadosomatic index (GSI) and mean oocyte size were observed under 24L:0D followed by 20L:4D and 16L:8D photoperiods, and these parameters were significantly higher than those of fish cultured under the short–no day photoperiod regimes (p?<?0.05). Proportion of females with GSI?>?9 % were 50.00 %, 46.67 %, 48.48 %, in 24L:0D, 20L:4D and 16L:8D, respectively. These results demonstrate that the growth of juvenile P. parva can be stimulated significantly by constant–long photoperiods and that these photoperiods can advance sexual maturity of females by approximately 2 months.