Effect of Irradiance Level and Paclobutrazol on Reducation of Leaf Damage in Begonia × cheimantha

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446d-446
Author(s):  
Beyounghan Yoon ◽  
Harvey J. Lang
Keyword(s):  
Day Treatment ◽  
Leaf Damage ◽  
Growth Retardants ◽  
Damage Development ◽  
Long Day ◽  
Leaf Chlorosis ◽  
Shade Cloth ◽  
Growing Conditions ◽  
Reduced Light ◽  
Shade Plants

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.

scholarly journals Photoperiodic Response of Peanut Species1

1983 ◽  
Vol 10 (2) ◽  
pp. 59-62 ◽  
Author(s):  
H. T. Stalker ◽  
J. C. Wynne
Keyword(s):  
North Carolina ◽  
Day Treatment ◽  
Photoperiodic Response ◽  
Reproductive Capacity ◽  
Arachis Species ◽  
Short Day ◽  
The North ◽  
Long Day ◽  
Wild Peanut ◽  
Short Days

Abstract Many Arachis species collections do not produce pegs in North Carolina even though they flower profusely. To investigate reasons for the failure of fruiting, nine wild peanut species of section Arachis and three A. hypogaea cultivars representing spanish, valencia and virginia types were evaluated for response to short and long-day treatments in the North Carolina State Phytotron Unit of the Southeastern Environmental Laboratories. The objective of this investigation was to determine the flowering and fruiting responses of Arachis species to short and long-day photoperiods. Plant collections grown under a 9-hour short-day treatment were generally less vigorous, but produced more pegs than corresponding plants grown in long-day treatments which were produced by 9 hours of light plus a 3-hour interruption of the dark period. Annual species produced significantly more flowers and pegs than perennial species during both long and short days. The total number of flowers produced ranged from 0 during short days for A. correntina to more than 300 for A. cardenasii in long-day treatments. Only one plant of each species A. chacoense and A. villosa, and no plants of A. correntina, flowered in short days. Total numbers of pegs produced in short-day treatments were generally greater than in long-day treatments and the ratio of total number of pegs/total number of flowers was consistently greater during short-day treatments. A general trend was observed for more flowers produced in long-day treatments, but more pegs produced in short days. This study indicated that photoperiod can be manipulated to increase the seed set of some species and the success rate of obtaining certain interspecific hybrids. Furthermore, introgression from wild to cultivated species may possibly alter the reproductive capacity of A. hypogaea to photoperiod.

Hochelaga lettuce

2008 ◽  
Vol 88 (3) ◽  
pp. 551-553 ◽  
Author(s):  
Sylvie Jenni ◽  
George C Emery
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Organic Soil ◽  
Organic Soils ◽  
Physiological Disorder ◽  
Long Day ◽  
Lactuca Sativa L ◽  
Lettuce Breeding ◽  
Growing Conditions ◽  
Horticultural Research

Hochelaga is an early and heavy crisphead lettuce highly tolerant to bolting under long-day growing conditions (more than 13-h). Hochelaga is the first variety released by the Horticultural Research and Development Centre (HRDC) lettuce breeding program of Agriculture and Agri-Food Canada (AAFC), Saint-Jean-sur-Richelieu, Quebec. Very similar in appearance to Ithaca, the regional standard, Hochelaga is well adapted to organic soils. Hochelaga is more tolerant than Ithaca to rib discoloration, a physiological disorder caused by high-temperature growing conditions. Key words: Lactuca sativa L., crisphead lettuce, rib discoloration, bolting, heat stress, organic soil

scholarly journals Methods of Long-day Treatment to Promote Flowering for Winter and Spring Shipping of Eustoma grandiflorum (Raf.) Shinn.

2008 ◽  
Vol 7 (3) ◽  
pp. 407-412 ◽  
Author(s):  
Asuka Yamada ◽  
Takahiro Tanigawa ◽  
Takuro Suyama ◽  
Takatoshi Matsuno ◽  
Toshihiro Kunitake
Keyword(s):  
Day Treatment ◽  
Eustoma Grandiflorum ◽  
Long Day

scholarly journals 018 EFFECTS OF ANCYMIDOL, PACLOBUTRAZOL, AND UNICONAZOLE ON GROWTH AND FLOWERING OF ACHIMENES cv HILDA UNDER TWO LIGHT LEVELS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 430b-430
Author(s):  
J. C. Vlahos
Keyword(s):  
Plant Height ◽  
Light Level ◽  
The Other ◽  
Growth Retardants ◽  
Axillary Shoots ◽  
Full Sunlight ◽  
Foliar Sprays ◽  
Light Levels ◽  
Mode Of Application ◽  
Reduced Light

Plants of Achimenes cv Hilda were treated with foliar sprays of Ancymidol, Paclobutrazol and Uniconazole at 3 different concentrations each, and were placed in a greenhouse at 21°C under 2 light levels (0 and 40% light exclusion) for 12 weeks. Reduced light level decreased plant height, number of axillary shoots and flowers. The three growth retardants in any concentration, supressed development of axillary shoots and flowers. Ancymidol at 25 and 50 mg.1-1, Uniconazole at 5 mg.1-1 and Paclobutrazol at 25, 50 or 100 mg.1-1 decreased plant height and number of leaf whorls. Number of rhizomes was reduced by the 3 chemicals at the highest concentration only. Paclobutrazol was most effective than the other 2 growth retardants. Effects of treatments were more pronounced under shade rather than in full sunlight. Days to anthesis was not affected by any of the treatments except by Paclobutrazol at 100 mg.1-1. The use of these growth retardants in concentration and mode of application similar to those used in this study is not recommended for “Hilda” as height retardation significantly reduces number of flowers

scholarly journals 763 PB 307 ENVIRONMENTAL CONTROL ON FLOWERING AND GROWTH OF LYSIMACHIA CONGESTIFLORA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 542c-542
Author(s):  
Donglin Zhang ◽  
Allan M. Armitage ◽  
James M. Affolter ◽  
Michael A. Dirr
Keyword(s):  
Environmental Control ◽  
Day Treatment ◽  
Dry Weight ◽  
High Irradiance ◽  
Flower Initiation ◽  
Low Light ◽  
The North ◽  
Long Day ◽  
Total Plant ◽  
Lower Temperature

Lysimachia congestiflora Wils. (Primulaceae) is a new crop for American nurseries and may be used as an annual in the north and a half-hardy perennial in the south. The purpose of this study was to investigate the influence of photoperiod, temperature, and irradiance on its flowering and growth. Three experiments were conducted with photoperiod of 8, 12, 16 hrs day-1, temperature of 10, 18, 26C, and irradiance of 100, 200, 300 μmol m-2s-1, respectively. Plant.9 given long day photoperiod (16 hours) flowered 21 and 34 days earlier, respectively, than plants at 12 sad 8 hour photoperiods. Plants under long day treatment produced more flowers than those at 8 and 12 hours. Plant dry weight did not differ between treatments, but plants grown in the long day treatment produced fewer but larger leaves. Total plant growth increased as temperature increased, but lower temperature (10C) decreased flower initiation and prevented flower development, while high temperature (26C) reduced the longevity of the open flowers. Flowering was accelerated and dry weight increased as plants were subjected to high irradiance levels. The results suggest that Lysimachia congestiflora is a quantitative long day plant. It should be grown under a photoperiod of at least 12 hours at a temperature of approximately 20C. Low light areas should be avoided and supplemental lighting to provide the long days may improve the plant quality.

scholarly journals Effect of Intermittent Long-day Treatment on Flowering of Branch Crown and Yield in Everbearing Strawberry Cultivars

2021 ◽  
Vol 20 (2) ◽  
pp. 171-177
Author(s):  
Takayoshi Yano ◽  
Takafumi Kinoshita ◽  
Hiromichi Yamazaki ◽  
Kaori Nagasuga ◽  
Hiroko Yamazaki ◽  
...  
Keyword(s):  
Day Treatment ◽  
Long Day ◽  
Branch Crown ◽  
Strawberry Cultivars

scholarly journals Effect of Photosynthetic Photon Flux and Temperature on Floral Evocation and Development in the Vernalization-sensitive Ornamental Perennial Salvia ×superba `Blaukönigin'

2006 ◽  
Vol 131 (4) ◽  
pp. 437-444 ◽  
Author(s):  
Grete Waaseth ◽  
Roar Moe ◽  
Royal D. Heins ◽  
Svein O. Grimstad
Keyword(s):  
Day Treatment ◽  
Leaf Number ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Flower Bud ◽  
Vegetative Development ◽  
Long Day ◽  
Floral Primordia ◽  
Subsequent Flowering ◽  
Floral Evocation

Varying photothermal ratios (PTR) were supplied to Salvia ×superba Stapf `Blaukönigin' during pre-inductive vegetative development with the exception of a short germination period under uniform conditions. In addition, both unvernalized plants and plants receiving a saturating vernalization treatment of 6 weeks at 5 °C were given two photosynthetic photon flux (PPF) levels (50 or 200 μmol·m-2·s-1) during subsequent inductive 16-hour long days. There were no effects of PTR treatments during vegetative development on subsequent flowering. However, the higher PPF level during inductive long days significantly accelerated floral evocation in unvernalized plants, lowering the leaf number at flowering. The effect was practically negligent after the vernalization requirement was saturated. In a second experiment, varying periods (4, 7, 10, and 14 days or until anthesis) at a PPF of 200 μmol·m-2·s-1 during 20-hour days were given at the beginning of a long-day treatment, either with or without preceding vernalization treatment. Flowering percentage increased considerably as the period at 200 μmol·m-2·s-1 was extended compared with plants grown at a lower PPF of 50 μmol·m-2·s-1. However, the leaf number on flowering plants was not affected, except in unvernalized plants receiving the highest PPF continuously until anthesis, where leaf number was reduced by almost 50%. We propose that the PPF-dependent flowering is facilitated either by the rate of ongoing assimilation or rapid mobilization of stored carbohydrates at the time of evocation. Abortion of floral primordia under the lower PPF (50 μmol·m-2·s-1) irrespective of vernalization treatment indicates that the assimilate requirement for flower bud development is independent of the mechanism for floral evocation.

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