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.     

Dormancy and Flowering in Anemone coronaria L. as Affected by Photoperiod and Temperature

The effects of day-length and temperature on flowering and dormancyinduction were studied in Anemone coronaria L., with plantsraised either from corms or achenes. An Israeli hybrid sourcewas used (de Caen cv. Hollandia x Israeli wild type). Dormancy onset is characterized by the cessation of foliageleaf production, the appearance of leaf scales protecting theperennating bud, and leaf senescence. Dormancy was induced byhigh temperature and long days but increasing temperatures (from17/12 °C to 32/12 °C) induced earlier dormancy thanprolonging the photoperiod (range 8–16 h). A significant(P = 0.01) interaction was found between these factors, withsmaller photoperiodic effects the higher the temperature. At22/17 °C the critical day-length for dormancy inductionwas between 11 and 12 h. The transition from the vegetative to the reproductive stageappears to be an autonomous process that occurs with developmentin plants raised from either corms or achenes and does not requireenvironmental induction. Photo- and thermoperiodic effects onflowering were indirect, being mediated through their influenceon dormancy induction. Anemone coronaria L., dormancy, flowering, photoperiod, thermoperiod     

Effects of Temperature and Photoperiod on Flowering in Chickpeas (Cicer arietinum L.)

Factorial combinations of two photoperiods (12 and 15 h), threeday temperatures (20, 25 and 30 °C) and three night temperatures(10, 15 and 20 °C) were imposed on nodulated plants of ninechickpea genotypes (Cicer arietinum L.) grown in pots in growthcabinets. The times to first appearance of open flowers wererecorded. For all genotypes, the rates of progress towards flowering(the reciprocals of the times taken to flower) were linear functionsof mean temperature. There were no interactions between meantemperature and photoperiod but the longer photoperiod increasedthe rate of progress towards flowering. These effects were independentof both radiation integral (the product of irradiance and photoperiod)and the vegetative stature of the plant. Taken in conjunctionwith evidence from work on other long-day species, it is suggestedthat the photo-thermal response of flowering in chickpeas, overthe range of environments normally experienced by the crop,may be described by the equation: 1/f = a+b     

Effects of Temperature and Photoperiod on Flowering in Lentils (Lens culinaris Medic.)

Factorial combinations of three photoperiods (10, 13 and 16h), two day temperatures (18 and 28 C) and two night temperatures(5 and 13 C) were imposed on nodulated plants of six diversegenotypes (cultivars and land-races) of lentil (Lens culinarisMedic.) grown in pots in growth cabinets from vernalized (1.50.5 C for 30d) or non-vernalized seeds (i.e. 144 ‘treatment’combinations). The times from sowing to the appearance of firstopen flowers were recorded. Vernalization, long days and warmtemperatures hastened flowering but genotypes differed in relativesensitivity to each of these factors and in time to floweringin the same most-inductive environment. Rates of progress towardsflowering (i.e. 1/f the reciprocals of the times to first flower,f) in all genotypes, vernalized or not, were linear functionsof both mean temperature,     

Effects of Temperature, Photoperiod and Seed Vernalization on Flowering in Faba Bean Vicia faba

Factorial combinations of three photoperiods (10, 13 and 16h), two day temperatures (18 and 28 °C) and two night temperatures(5 and 13 °C) were imposed on nodulated plants of six diversegenotypes of faba bean (Vicia faba L.). Plants were grown inpots in growth cabinets from both vernalized (1.5±0.5°C for 30 d) and non-vernalized seeds. The times from sowingto the appearance of first open flowers (f) were recorded. Seedvernalization decreased the subsequent time taken to flowerin almost all genotype x growing environment combinations (theexceptions were plants of the cv. Maris Bead grown in threecooler, short-day regimes). The influence of temperature andphotoperiod on the rate of flowering was quantified, using amodel applied previously to other long-day species of grainlegume in which positive linear relations between both temperatureand photoperiod and the rate of progress towards flowering areassumed to apply. A significant positive linear response ofrate of progress towards flowering to limited ranges of meandiurnal temperature was detected in all six genotypes, but inthree genotypes (Syrian Local Large, Aquadulce and Maris Bead)the 28 °C day temperature reduced the rate of progress towardsflowering - suggesting that the optimum temperature for floweringin these genotypes is below 28 °C. In four genotypes (MarisBead, Giza-4, Aquadulce and BPL 1722) a significant positiveresponse to photoperiod, typical of quantitative long-day plants,was observed only in plants grown from vernalized seeds. Incontrast, plants of the genotype Zeidab Local grown from bothnon-vernalized and vernalized seeds showed the same positiveresponse to photoperiod, whereas plants of the land-race SyrianLocal Large were consistently unresponsive to photoperiod. Theimplications of this range of responses amongst diverse genotypesare discussed in relation to screening germplasm. Vicia faba, faba bean, flowering, photoperiod, temperature, seed vernalization, germplasm screening     

Flowering of Contrasting White Clover Varieties in Relation to Temperature in Controlled Environments

Effects of temperature on floral initiation of ten white clovervarieties growing in controlled environments are described.Plants grown under long days (16 h) were subjected to constanttemperatures of 26, 18 and 10 ^°C. Relationships betweenmorphological and physiological traits and flowering were examined. Most plants flowered at the two higher temperatures but only10 per cent of plants flowered at 10 ^°C. Larger leaved typestended to produce more reproductive buds per stolon at the highertemperatures than did smaller leaved varieties. Of the floral characters studied, floret number was least affectedby temperature. Ovule number and peduncle length were greatestat 18 ^°C. Variation in, and absolute level of nectar secretionwas greatest at the highest temperature. Trifolium repens, white clover, flowering, temperature     

Comparative Root Anatomy of Five Actinidia Species in Relation to Rootstock Effects on Kiwifruit Flowering

This study examined the root anatomy of five Actinidia specieswhich, when used as rootstocks, differ in their effects on flowerproduction of the 'Hayward' kiwifruit scion. The rootstock speciesexamined were A. hemsleyana, A. eriantha, A. rufa, A. deliciosaand A. chinensis. Roots of all the five species had similartissues and similar cell types in each tissue. The cortex andendodermis were retained and developed further during secondaryroot thickening. Each meriphyte of endodermal cells, derivedduring secondary growth, was enclosed in a suberin lamella.Crystalline idioblasts were present in the cortex and phloem.These idioblasts contained raphide crystals, often surroundedby mucilage. Roots of the five species differed significantlyin the total cross-sectional area of vessels in the xylem, inthe total cross-sectional areas of fibres and crystalline idioblastsin the phloem, and in the abundance of starch grains in parenchymaof all tissues. Roots of flower-promoting rootstock speciestended to have more and larger xylem vessels, more crystallineidioblasts, and more starch grains. These anatomical featuresmay be used as criteria for future selection of flower-promotingrootstocks in kiwifruit. The possible physiological link betweenroot anatomy and rootstock effect is discussed.Copyright 1994,1999 Academic Press Kiwifruit, Actinidia, root, anatomy, rootstock, flowering     

Comparative Ontogeny of Behaviour in Four Species of Squirrels (Sciuridae)

The development of behaviour in four species of Sciurid rodents, having terrestrial, arboreal and gliding way of life, is quantified and compared. The studied species are: Spermophilus columbianus, Spermophilus lateralis, Tamiasciurus hudsonicus and Glaucomys sabrinus. For each behaviour pattern, the earliest and latest age of emergence is given along with a mean calculated for a series of young of each species. The development of locomotion, feeding, comfort, alertness, exploration, nest building and social behaviour and the principal events of physical development are analysed. The discussion shows that the specific differences in ontogenetic rate are controlled by a series of factors including predation pressure, hibernation and the specific complexity of locomotion.     

光周期途径植物开花决定关键基因FT

随着分子生物学的快速发展,大量与光周期途径开花相关的基因已经被发现和克隆,刀(FLOWER-ING LOCUS T)是光周期途径植物开花时间决定关键基因,并认为刀基因表达产物可能就是人们长期追寻的开花刺激物质,这种开花刺激物质经过叶片到茎尖的长距离运输,最终引起茎顶端开花起始.目前已在多种植物中分离出FT同源基因,并通过转基因证明FT基因的表达可促进植物提早开花.本文对国内外关于FT基因家族的研究进展进行综述,旨在为进一步深入研究FT基因功能提供参考.     

A Homolog of the Substrate Adhesion Molecule Vitronectin Occurs in Four Species of Flowering Plants

The extracellular matrix (ECM) has been implicated in the primary developmental processes of many organisms. A family of secretory adhesive glycoproteins called substrate adhesion molecules (SAMs) is believed to confer these dynamic capabilities to the ECM in animals. In this paper, we report the existence of SAM-like genes and gene products in flowering plants. Hybridizations with a human vitronectin cDNA probe and genomic DNA from broad bean, soybean, and tomato revealed vitronectin-like sequences. Human vitronectin antibodies cross-react with a 55-kilodalton protein in leaf and root protein extracts from lily, broad bean, soybean, and tomato. In addition, immunocytochemical staining of frozen sections of lily leaf and broad bean gynoecium demonstrated that vitronectin-like proteins were localized to the ECM on the cell surface, with the most intense labeling residing in the transmitting tract of broad bean gynoecium.     

Growth Cycle Metabolism of Plants in Relation to Flowering

An examination of the percentages of total carbohydrate, nitrogen (Kjeldahl) and ash has been made at various times in the growth cycle in six plants of varying growth habit. The time of formation of the flower initial in four species (fumitory, leek, radish and yellow water-lily) corresponds to a maximum in the curve showing percentage of total carbohydrate plus percentage of ash in the whole plant. The other two species (pea and bean) make their flower initials very early in the growth cycle, at a time when the amounts of carbohydrate plus ash are high because of the attachment of the plant to the large seed. These two species therefore also make their flower initials at a virtual maximum of carbohydrate plus ash. All six species of plants studied have mobile carbohydrate. The distribution of nutrients after flowering is discussed.     

Rates of Progress towards Flowering and Podding in Bambara Groundnut (Vigna subterranea) as a Function of Temperature and Photoperiod

The influence of temperature and photoperiod on phenologicaldevelopment of three bambara groundnut (Vigna subterranea) selectionsfrom Botswana, Zimbabwe and Mali was investigated in a semi-controlledenvironment experiment with factorial combinations of threeconstant temperatures (20.9, 23.4 and 26.2 °C) and fourconstant photoperiods (10.0, 12.5, 13.5 and 16.0 h d^-1). Inall three selections, the onset of flowering was influencedby temperature but not by photoperiod, while the onset of pod-growth(‘podding’) of all three selections was influencedby both factors. The influence of temperature and photoperiodwas quantified by means of photothermal models, linking developmentrates to temperature and photoperiod with linear equations.The rate of progress from sowing to flowering of the three selectionscould be described very well (r²>95%) as a function of temperature;the rate of progress from flowering to podding was describedreasonably well as a function of both temperature and photoperiodby a combination of one to three response planes (r²for thedifferent selections ranging from 63 to 90%). Model testingwith independent data sets showed good agreement between observedand predicted times to flowering and podding. Vigna subterranea; Voandzeia subterranea; bambara groundnut; phenology; development; flowering; podding; photoperiod; temperature; modelling     

控制拟南芥和水稻开花时间光周期途径的分子机制

就拟南芥和水稻开花时间控制光周期途径的分子机制的研究进展作简要介绍。     

光周期对春石斛开花及多胺含量的影响

以春石斛为试材,研究光周期对其开花及多胺（腐胺、亚精胺和精胺）含量的影响,以期了解春石斛开花的光周期特性以及期间能源物质多胺的变化规律。结果显示,春石斛短日照处理植株开花较长日照处理的提前约18d,为称量性短日照植物;同时,短日照处理植株的花芽多,开花量犬,花径较长日照大。不同光周期诱导开花过程中,春石斛叶片内腐胺含量最高,波动较大,短日照处理下基本维持比长日照高的水平。亚精胺含量其次,且随生长发育逐渐升高,短日照处理下一直保持比长日照高的水平。精胺含量最低,变化不大,短日照下保持与长日照相同或略高的水平。由此推测,春石斛为称量性短日照植物,高水平的腐胺和亚精胺可能与春石斛花芽的形成有关。