THE EFFECT OF LIGHT INTENSITY AND TEMPERATURE ON FLORAL INITIATION AND INFLORESCENCE DEVELOPMENT OF MARQUIS WHEAT

1963 ◽  
Vol 41 (12) ◽  
pp. 1663-1674 ◽  
Author(s):  
D. J. C. Friend ◽  
J. E. Fisher ◽  
V. A. Helson
Keyword(s):  
Light Intensity ◽  
Apical Meristem ◽  
High Light ◽  
Leaf Primordia ◽  
Leaf Number ◽  
Continuous Illumination ◽  
Floral Initiation ◽  
Main Shoot ◽  
Inflorescence Development ◽  
Effect Of Light

Under continuous illumination, floral initiation was earlier with each increase in light intensity from 200 to 2500 ft-c, and with each increase in temperature between 10 and 30 °C. This effect of light intensity is attributed to promotion of floral initiation by energy in the far-red (730 mμ).The rate of formation of leaf primordia was accelerated by increases in light intensity to a greater extent than floral initiation, so that the final leaf number on the main shoot was greatest for the plants grown at high light intensities. Between 10 and 25 °C an increase in temperature had similar effects on the rate of formation of leaf primordia and floral initiation, so that the final leaf number was not altered. The final leaf number was lower at 30 °C than at 25 °C because leaf primordium formation was retarded.After floral initiation, the growth of the apical meristem was most rapid at 30 °C and 2500 ft-c, resulting in the earliest heading and anthesis (33 and 38 days). Low temperatures strongly retarded the later stages of ear development and emergence.

Effect of phosphorus applied as superphosphate on rate of development and spikelet number per ear of different cultivars of wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Constant Temperature ◽  
Leaf Number ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Main Shoot ◽  
Spikelet Number ◽  
Vegetative Phase ◽  
Rate Of Development ◽  
Elongation Phase

The effects of adding phosphorus (40 kg of phosphorus ha-1) at sowing on rate of development, spikelet number per ear, rate of spikelet initiation, apex length at floral initiation, and leaf number at ear emergence of the main shoot of seven wheat cultivars were studied under a 16 hr photoperiod at a constant temperature of 20°C. Phosphorus additions increased the spikelet number per ear, rate of spikelet initiation, and apex length significantly in all wheats, but had no effect on the duration of the vegetative phase, spikelet phase or elongation phase, or on leaf number. The increase in spikelet number was due to an increase of spikelet initiation. All wheats responded similarly to addition of phosphorus.

scholarly journals Effect of light intensity and growth substratum on plant development and production of secondary metabolites in Cordia curassavica (Jacq.) Roem. & Schult

2010 ◽  
Vol 34 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Maria Terezinha Silveira Paulilo ◽  
Flávia Simão Lapa ◽  
Miriam de Barcellos Falkenberg
Keyword(s):  
Light Intensity ◽  
Root Biomass ◽  
Relative Income ◽  
High Light Intensity ◽  
High Light ◽  
Alcoholic Extract ◽  
Low Light ◽  
Fertilized Soil ◽  
Lower Light ◽  
Effect Of Light

Cordia curassavica (Jacq.) Roem. & Schult. (Boraginaceae), also referred to as Cordia verbenacea DC, has been traditionally used for medicinal purposes. This study was driven to verify the behavior of the species in similar conditions to its natural environment, such as high light intensity and sandbank soil, and in conditions of low light intensity and fertilized substratum (dystroferric red nitosoil plus earthworm humus). The growth of the plant, the income of leaf crude extracts and, in the alcoholic extract, the number of substances found in thin layer cromatography and the toxicity of the substratum was observed. The results indicated that the growth of the root biomass, stem and leaves in discharge or lower light intensity was similar, but smaller in sandbank soil than in fertilized soil. The relative income of extracts in ether of petroleum and alcohol was larger in high light intensity and fertilized substratum. The light intensity and the substratum type didn't affect the number of substances detected in the alcoholic extract or the toxicity of this extract. Stains corresponding to the rosmarinic acid were only evidenced in some samples of the alcoholic extract, not allowing the verification of the effect of the treatments about its production.

Factors affecting growith and distribution of kauri (Agathis australis Salisb.) I. Effect of light on the establishment of Kaura and of Phyllocladus trichomanoides D.Don

1959 ◽  
Vol 7 (3) ◽  
pp. 252 ◽  
Author(s):  
RL Bieleski
Keyword(s):  
Light Intensity ◽  
Frequency Distribution ◽  
High Light Intensity ◽  
High Light ◽  
Low Light ◽  
Factors Affecting ◽  
Light Intensities ◽  
Seedling Distribution ◽  
Conifer Seedling ◽  
Effect Of Light

A method for determining the effect of light on seedling distribution in the field is described. It can be applied when seedling frequencies are as low as 1/m2. The frequency distribution of light intensities occupied by seedlings in a quadrat is compared with the frequency distribution of light intensities measured on a grid in the quadrat. This method was used to study the effect of light intensity on the establishment of two New Zealand gymnosperms, kauri (Agathis australis) and Phyllocladus trichomanoides, in the nursery community, a semimature Leptospermum scoparium – L. ericoides associes. Kauri and Phyllocladus did not occur at light intensities below 0.015 and 0.018 full daylight respectively. This limitation appeared to be due to the low light intensity presumably limiting photosynthesis. Kauri, but not Phyllocladus, also showed a high light intensity limit, at 0.30 full daylight, above which seedlings did not establish. Reasons are given for considering this as an indirect effect, probably through related solar heating affecting soil temperature or moisture. The optimal light intensity for kauri and Phyllocladus seedling establishment was close to the modal light intensity under the Leptospermum community: Leptospermum spp. were incapable of regenerating under their own cover. These two reasons appear to explain the suitability of the Leptospermum community as a nurse crop for the two conifer seedling species.

scholarly journals MACROMOLECULAR PHYSIOLOGY OF PLASTIDS

1970 ◽  
Vol 44 (2) ◽  
pp. 290-304 ◽  
Author(s):  
K. W. Henningsen ◽  
J. E. Boynton
Keyword(s):  
Electron Microscopy ◽  
Light Intensity ◽  
Thin Layer ◽  
High Light Intensity ◽  
High Light ◽  
Continuous Illumination ◽  
Prolamellar Bodies ◽  
Chlorophyll A And B ◽  
Layer Chromatography

Sequential changes occurring in the etioplasts of the primary leaf of 7-day-old dark-grown barley seedlings upon continuous illumination with 20 lux have been investigated by electron microscopy, in vivo spectrophotometry, and thin-layer chromatography. Following photoconversion of the protochlorophyllide pigment to chlorophyllide and the structural transformation of the crystalline prolamellar bodies, the tubules of the prolamellar bodies are dispersed into the primary lamellar layers. As both chlorophyll a and b accumulate, extensive formation of grana takes place. After 4 hr of greening, protochlorophyllide starts to reaccumulate, and concomitantly both large and small crystalline prolamellar bodies are formed. This protochlorophyllide is rapidly photoconverted upon exposure of the leaves to high light intensity, which also effects a rapid reorganization of the recrystallized prolamellar bodies into primary lamellar layers.

scholarly journals Experimental investigations of the shoot apex of Dryopteris aristata Druce

1947 ◽  
Vol 232 (589) ◽  
pp. 343-384 ◽  
Keyword(s):  
Shoot Apex ◽  
Apical Meristem ◽  
Vascular Tissue ◽  
Normal Development ◽  
Vascular System ◽  
Leaf Primordia ◽  
Terminal Region ◽  
Main Shoot ◽  
Marked Contrast ◽  
Medullary Parenchyma

A method whereby the apical meristem of the fern Dryopteris aristata Druce can be partially isolated from the adjacent lateral organs and tissues is described. This procedure has been adopted as a means of investigating growth and morphogenesis at the shoot apex. The technique involves the severance of the incipient vascular tissue which originates immediately below the apical meristem; the isolated meristem is thus seated on a plug of growing medullary parenchyma. Leaf primordia can be similarly isolated. Meristems treated in this way are capable of growth. They develop into short vasculated shoots bearing leaves. The nutrients sustaining this growth must reach the apical meristem from below by diffusing through medullary parenchyma at the base of the isolated terminal region. Above the parenchymatous region a solenostelic vascular system is present in the new axis; this is in marked contrast to the dictyostelic configuration of the parental shoot below. On the further growth of the isolated meristem leaves are produced and the stele becomes dictyostelic. The new leaves, of which as many as fourteen have been observed after 11 weeks’ growth, show the normal phyllotactic arrangement, and this is continuous with that of the main shoot below. The procedure adopted has the effect of removing the physiological dominance of the apical meristem relative to the main shoot; thus numerous large buds develop on the lateral segments of the parental shoot but none on the isolated terminal region. The growth of isolated leaf primordia is very limited. The vascular system develops as a solenostele, foliar gaps are not formed in the region of confluence with the shoot stele, axillary buds are developed, and the leaf apex becomes directed outwards. These several features are in marked contrast to the normal development. The isolated lateral segments are also capable of further growth. The experimental procedure adopted involves the severance of the vascular tissues at various levels. An account is given of new and hitherto unrecorded morphological developments observed in these segments. Interesting features include the formation of large solenostelic buds, the solenostelic development of isolated meristeles, medullation of meristeles and the induction of a polycyclic stelar condition, in one instance by a process of cambium-like activity. These are all in marked contrast to the normal development of the intact shoot. The data which have been obtained are discussed with special reference to the path of translocation of nutrients to the terminal meristem and to leaf primordia, morphogenetic processes at the shoot apex, the factors influencing the differentiation of the vascular system, and theories of shoot formation and constitution. The results of these experiments give no support to phytonic theories but emphasize the difference in potentiality for development between shoot and leaf primordia. In this connexion the factors which determine the shape and system of segmentation of the apical initials of shoot and leaf are seen to require further investigation. The hypotheses that lateral buds are inhibited by substances proceeding from the apical meristem, that the initial differentiation of vascular tissue can be attributed to the basipetal diffusion of a substance or substances from the actively growing apical meristem, and that under conditions of tensile stress incipient vascular tissue undergoes a parenchymatous development, are supported by the data of these experiments. The observations afford a clear indication of the diversity of the morphogenetic activity in the growing region. Nutritional, mechanical and other factors are seen to be important in influencing the distribution of tissues during development. The view entertained by comparative morphologists that the vascular system in ferns is of a highly conservative nature and therefore of great value in phyletic studies is to some extent opposed by the data of these experiments. But notwithstanding the several unusual vascular configurations produced as a result of the experimental treatment, there is eventually a return to the typical vascular arrangements of the normal shoot. There is thus a need for harmonizing the data of the causal and phyletic aspects. The more thoroughly the operation of morphogenetic factors extrinsic to the specific hereditary substance is understood, the more critical will be the selection of criteria of comparison for phyletic purposes.

scholarly journals The Effect of Light Intensity and Temperature on Flowering and Morphology of Potted Red Firespike

Horticulturae ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 36 ◽  
Author(s):  
Amir Rezazadeh ◽  
Richard Harkess ◽  
Telmah Telmadarrehei
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Growth Index ◽  
Flowering Plant ◽  
Experimental Conditions ◽  
Open Flower ◽  
Inflorescence Development ◽  
Branch Number ◽  
Response To Temperature ◽  
Effect Of Light

Red firespike (Odontonema strictum) is a tropical flowering plant that was selected as a potential flowering potted plant for its attractive red floral spikes. The objective of this study was to evaluate how light intensity, photoperiod, and temperature affect the growth and flowering of firespike. In Experiment 1, plants were grown under 0%, 45%, or 65% shade and two photoperiod conditions; long-day (LD = ≥14 h) and short-day (SD = 9 h), for 16 weeks. Plants grown under 45% shade + LD were tallest at 35.9 cm, while plants grown under 65% shade + SD were shortest at 22.8 cm. During the finishing stage, the number of inflorescences increased when plants were grown under 45% shade + SD, 45% shade + LD, and no shade, with 6, 7, and 9 inflorescences, respectively. In addition, the first open flower was observed in the 0% shade group (control) 92 days after starting the experiment. The time to first open flower increased when the plants were grown under 65% shade, either under SD or LD. In Experiment 2, plants were grown in controlled environment growth chambers with average daily temperatures of 15, 25, or 35 °C and an irradiance of 200 µmol·m−2·s−1 for 9 h per day. Plants grown at 25 °C were the tallest and had the largest leaf area. Plants grown at 15 and 35 °C had 28% and 22% less leaf area, respectively. The average number of inflorescences in plants grown at 25 °C was 1.6, while no inflorescence development was observed in plants grown at 15 or 35 °C by the termination of the experiment. There were no differences between plant growth index or branch number in response to temperature. Under the experimental conditions tested, the most rapid and uniform flowering of firespike occurred when plants were grown under no shade or at 25 °C.

Novel variation in the floral development of two species of Parthenocissus

2003 ◽  
Vol 81 (7) ◽  
pp. 738-748 ◽  
Author(s):  
Trevor Wilson ◽  
Usher Posluszny
Keyword(s):  
Early Development ◽  
Apical Meristem ◽  
Floral Development ◽  
Late Development ◽  
Main Shoot ◽  
Inflorescence Development ◽  
Parthenocissus Tricuspidata ◽  
Parthenocissus Quinquefolia ◽  
Previous Assumption ◽  
Novel Variation

This study compares the development of the inflorescences and flowers of Parthenocissus quinquefolia (Virginia creeper) and Parthenocissus tricuspidata (Boston ivy). The development of the reproductive shoots is described from inception to maturity using epi-illumination and scanning electron microscopy. In both species, the shoot apex initiates inflorescence primordia low on the apical flank. An inflorescence primordium produces several bract-opposed branches, which in early development resembles the main shoot. As inflorescence development continues, branch primordia initiate as increasingly larger portions than the inflorescence apical meristem. By late development, branch primordia initiate as larger portions than the apex, which is a process that has been observed in other vitaceous inflorescences. With respect to initiation and early development, the Parthenocissus inflorescence is very similar to the tendril, which has been previously studied; these two organs have never been described to be so similar, and their likeness to the shoot, in early development, provides an idea as to how they may have arisen. An inflorescence branch terminates as a dichasium, which is formed by two nearly simultaneous branching events. Parthenocissus tricuspidata flowers develop a more robust gynoecial disc and stigma than in the P. quinquefolia flower; but the calyx is ring-like in the former and cup-like in the latter. Contrary to the previous assumption that there are no differences in reproductive biology within genera of the Vitaceae, this study has clearly demonstrated variation between two species of Parthenocissus.Key words: floral, development, monopodial, Parthenocissus, inflorescence, Vitaceae.

scholarly journals Interaction of vernalization, photoperiod and light intensity in floral initiation of endive.

1959 ◽  
Vol 7 (1) ◽  
pp. 68-74
Author(s):  
J.F. Harrington ◽  
K. Verkerk ◽  
J. Doorenbos
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Vegetative Growth ◽  
Day Treatment ◽  
High Light Intensity ◽  
High Light ◽  
Floral Initiation ◽  
Low Light ◽  
Short Days ◽  
Limited Period

Vernalization of germinating endive seed or of young endive plants hastened floral initiation, but at the expense of vegetative growth. High temperatures after vernalization promoted bolting. Long days hastened bolting in both vernalized and non-vernalized plants, again at the expense of vegetative growth. A limited period of short days immediately after sowing also promoted flowering, and it is suggested that such short-day treatment may act as a partial substitute for low temperature. High light intensity had a supplementary effect in promoting bolting but, in contrast to vernalization and long days, caused more rapid vegetative growth than low light intensity.-Lab. TuinbPl., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Cytological and histological changes induced by cold temperature in the young shoots of Marquillo × Kenya Farmer wheat dwarf 1

1972 ◽  
Vol 50 (3) ◽  
pp. 403-408 ◽  
Author(s):  
J. D. Mahon ◽  
D. T. Canvin
Keyword(s):  
Apical Meristem ◽  
Leaf Primordia ◽  
Vascular Bundles ◽  
Vascular Differentiation ◽  
Main Shoot ◽  
Histological Changes ◽  
Whole Plant ◽  
Meristematic Activity ◽  
Extensive Cell ◽  
Extent Of Damage

The growth of Marquillo × Kenya Farmer 1 heat plants has been shown to be irreversibly terminated if they are exposed to a 16° temperature when 10 days old and it has been proposed that this low temperature sensitivity proceeds through a rapid inactivation of the shoot apical meristem. Histological and microautoradiographic techniques were used to study the effects of 16° treatment on the morphology and meristematic activity of the young shoots of both Marquillo × Kenya Farmer 1 and normal Marquillo plants.Within 12 h of the beginning of 16° treatment, damaged cells were visible in the young developing leaf and stem tissues and such cells became numerous after longer periods at 16°. The cells most rapidly destroyed were those surrounding the vascular bundles in both leaf primordia and stem tissues and the extent of damage in a tissue was closely related to the stage of vascular differentiation in the adjacent bundles.Cell division in the apical meristem of the main shoot was inhibited even more rapidly. The proportion of cells dividing and the incorporation of 3H-thymidine into the nuclei of meristem cells decreased rapidly at 16° and the reversibility of these effects was similar to that of the whole plant effects.It is suggested that the cessation of growth in Mql × KF 1 exposed to 16° is due to the lack of cell division and that the permanence of this effect is due to the extensive cell destruction that occurs in the meristematic regions.

scholarly journals Effect of Light Intensity on the Rate of Apparent Photosynthesis in Coffee Leaves

1969 ◽  
Vol 46 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Marco A. Tió
Keyword(s):  
Light Intensity ◽  
Photosynthetic Activity ◽  
High Light ◽  
Light Saturation ◽  
Arabica Coffee ◽  
Light Intensities ◽  
Effect Of Light

The rate of apparent photosynthesis relative to light intensity was determined for Bourbon variety of Arabica coffee. A curve for the effect of light-saturation on apparent photosynthesis of coffee showed that saturation was reached at a maximum of 2,000 foot-candles and that maximum apparent photosynthesis was maintained up to 6,000 foot-candle intensity, after which it decreased. Evidence is also presented to demonstrate that high light intensities may cause an impairment of the photosynthetic activity.

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