scholarly journals Photosynthetic Daily Light Integral During the Seedling Stage Influences Subsequent Growth and Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1099C-1099
Author(s):  
Lee Ann Pramuk ◽  
Erik S. Runkle

The photosynthetic daily light integral (DLI) dramatically increases during the spring, but effects of DLI on seedling growth and development have not been characterized for many species. We quantified the effects of DLI on growth and development of Celosia, Impatiens, Salvia, Tagetes, and Viola during the seedling stage and determined whether there were any residual effects of DLI on subsequent growth and development after transplant. Seedlings were grown in growth chambers for 18–26 days at 21 °C with a DLI ranging from 4.1–14.2 mol·mol·m-2·d-1. Average seedling shoot dry weight per internode (a measure of quality) increased linearly 64%, 47%, 64%, and 68% within this DLI range in Celosia, Impatiens, Tagetes, and Viola, respectively. Seedlings were then transplanted to 10-cm containers and grown in a common environment (average daily temperature of 22 °C and DLI of 8.5 mol·m-2·d-1) to determine subsequent effects on plant growth and development. Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola occurred 10, 12, 11, 4, and 12 days earlier, respectively, when seedlings were previously grown under the highest DLI compared with the lowest. Except for Viola, earlier flowering corresponded with the development of fewer nodes below the first flower. Flower bud number and plant shoot dry weight at first flowering decreased as the seedling DLI increased in all species except for flower number of Tagetes. Therefore, seedlings grown under a greater DLI flowered earlier, but plant quality at first flowering was generally reduced compared with that of seedlings grown under a lower DLI.

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1336-1339 ◽  
Author(s):  
Lee Ann Pramuk ◽  
Erik S. Runkle

The photosynthetic daily light integral (DLI) dramatically increases during the spring when the majority of bedding plants are commercially produced. However, the effects of DLI on seedling growth and development have not been well characterized for most bedding plant species. Our objectives were to quantify the effects of DLI on growth and development of Celosia, Impatiens, Salvia, Tagetes, and Viola during the seedling stage and determine whether there were any residual effects of DLI on subsequent growth and development after transplant. Seedlings were grown in growth chambers for 18 to 26 days at 21 °C with a DLI ranging from 4.1 to 14.2 mol·m–2·d–1. Average seedling shoot dry weight per internode (a measure of quality) increased linearly 64%, 47%, 64%, and 68% within this DLI range in Celosia, Impatiens, Tagetes, and Viola, respectively. Seedlings were then transplanted to 10-cm containers and grown in a common environment (average daily temperature of 22 °C and DLI of 8.5 mol·m–2·d–1) to determine subsequent effects on plant growth and development. Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola occurred 10, 12, 11, 4, and 12 days earlier, respectively, when seedlings were previously grown under the highest DLI compared with the lowest. Except for Viola, earlier flowering corresponded with the development of fewer nodes below the first flower. Flower bud number and plant shoot dry weight at first flowering (plant quality parameters) decreased as the seedling DLI increased in all species except for flower number of Tagetes. Therefore, seedlings grown under a greater DLI flowered earlier, but plant quality at first flowering was generally reduced compared with that of seedlings grown under a lower DLI.


HortScience ◽  
2012 ◽  
Vol 47 (7) ◽  
pp. 856-860 ◽  
Author(s):  
Veronica A. Hutchinson ◽  
Christopher J. Currey ◽  
Roberto G. Lopez

Vegetatively propagated bedding plants are produced during the late winter and early spring when outdoor photosynthetic daily light integral (DLI) is low, especially in northern latitudes. Our objective was to quantify how propagation DLI influences subsequent growth and development of annual bedding plants. Cuttings of Angelonia angustifolia Benth. ‘AngelMist White Cloud’, Nemesia fruticans (Thunb.) Benth. ‘Aromatica Royal’, Osteospermum ecklonis (DC.) Norl. ‘Voltage Yellow’, and Verbena ×hybrida Ruiz ‘Aztec Violet’ were harvested and propagated in a glass-glazed greenhouse. After callusing (≈5 mol·m−2·d−1 for 7 days), cuttings of each species were placed under one of three different fixed-woven shadecloths providing ≈38%, 61%, or 86% shade or no shade with 16 h of supplemental light for 14 days. Rooted cuttings were then transplanted into 11-cm containers and grown in a common greenhouse of 21 ± 1 °C and DLI of ≈12 mol·m−2·d−1 to identify any residual effects on subsequent growth and development during the finish stage. As DLI during propagation increased, time to first open flower decreased for Angelonia, Nemesia, Osteospermum, and Verbena. For example, time to flower for Angelonia and Osteospermum was hastened by 23 and 19 days, respectively, as DLI during propagation increased from 1.2 to 12.3 mol·m−2·d−1. Our research can be used to predict growth and flowering under varying propagation DLIs for the cultivars of Angelonia, Nemesia, Osteospermum, and Verbena in the study.


HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2052-2059 ◽  
Author(s):  
Roberto G. Lopez ◽  
Erik S. Runkle

A majority of commercial propagation of herbaceous ornamental cuttings occurs during the winter when the photosynthetic daily light integral (DLI) is relatively low. We quantified how the mean DLI influenced rooting and subsequent growth and development of two popular vegetatively propagated species, New Guinea impatiens (Impatiens hawkeri Bull.) and petunia (Petunia ×hybrida hort. Vilm.-Andr.). Three cultivars of each species were propagated under a mean DLI ranging from 1.2 to 10.7 mol·m−2·d−1. Cuttings were rooted in a controlled greenhouse environment maintained at 24 to 25 °C with overhead mist, a vapor-pressure deficit of 0.3 kPa, and a 12-h photoperiod. Rooting and growth evaluations of cuttings were made after 8 to 16 d. In a separate experiment, rooted cuttings under DLI treatments were then transplanted into 10-cm containers and grown in a common greenhouse at 21 ± 2 °C under a 16-h photoperiod to identify any residual effects on subsequent growth and development. In both species, rooting, biomass accumulation, and quality of cuttings increased and subsequent time to flower generally decreased as mean propagation DLI increased. For example, root number of petunia ‘Tiny Tunia Violet Ice’ after 16 days of propagation increased from 17 to 40 as the propagation DLI increased from 1.2 to 7.5 mol·m−2·d−1. In addition, cutting shoot height decreased from 6.3 to 4.5 cm, and root and shoot dry biomass of cuttings harvested after 16 days of propagation increased by 737% and 106%, respectively. Subsequent time to flower for ‘Tiny Tunia Violet Ice’ from the beginning of propagation decreased from 50 to 29 days as propagation DLI increased from 1.4 to 10.7 mol·m−2·d−1 regardless of the DLI provided after propagation. In New Guinea impatiens ‘Harmony White’, root and shoot dry weight of cuttings increased by 1038% and 82%, respectively, and subsequent time to flower decreased from 85 to 70 days as the propagation DLI increased from 1.2 to 10.7 mol·m−2·d−1. These experiments quantify the role of the photosynthetic DLI during propagation on the rooting and subsequent growth and development of vegetatively propagated herbaceous ornamental cuttings.


2010 ◽  
Vol 20 (5) ◽  
pp. 929-933 ◽  
Author(s):  
Katherine F. Garland ◽  
Stephanie E. Burnett ◽  
Lois B. Stack ◽  
Donglin Zhang

Coleus (Solenostemon scutellarioides) traditionally has been recommended as a shade plant, but many cultivars are also suitable for full sun. In regions of the country where light limits growth and photosynthesis, supplemental lights are used to increase daily light integral (DLI). Understanding the minimum DLI necessary to produce coleus would minimize supplemental lighting use, reducing costs and improving production sustainability. ‘Kong Red’ and ‘Wizard Coral Sunrise’ coleus were grown in a greenhouse under a 12-hour photoperiod and a mean DLI of 2.9, 3.8, 5.8, or 10.0 mol·m−2·d−1 to determine the lowest light level needed to produce high-quality plants. After 8 weeks, both cultivars had a 4.2-fold increase in shoot dry weight as DLI increased from 2.9 to 10.0 mol·m−2·d−1. Plants grown under 10.0 mol·m−2·d−1 were 22% to 25% taller and 18% to 21% wider compared with those grown under 2.9 mol·m−2·d−1. ‘Kong Red’ had 3.6 times as many branches and ‘Wizard Coral Sunrise’ had over twice as many branches when grown under 10.0 mol·m−2·d−1 compared with those grown under the lowest DLI. Leaf counts for both cultivars were 64% greater when grown under the highest DLI compared with those produced under the lowest DLI; leaf area for both cultivars was also positively correlated with DLI. Leaves of both cultivars had significantly more green area (i.e., less variegation) when grown under lower DLIs. Overall, both cultivars exhibited a more dense growth habit and greater degree of variegation when grown under the highest DLI. Therefore, we recommend growing ‘Kong Red’ and ‘Wizard Coral Sunrise’ coleus under a minimum DLI of 10.0 mol·m−2·d−1.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 508e-508
Author(s):  
Bin Liu ◽  
Royal D. Heins

A concept of ratio of radiant to thermal energy (RRT) has been developed to deal with the interactive effect of light and temperature on plant growth and development. This study further confirms that RRT is a useful parameter for plant growth, development, and quality control. Based on greenhouse experiments conducted with 27 treatment combinations of temperature, light, and plant spacing, a model for poinsettia plant growth and development was constructed using the computer program STELLA II. Results from the model simulation with different levels of daily light integral, temperature, and plant spacing showed that the RRT significantly affects leaf unfolding rate when RRT is lower than 0.025 mol/degree-day per plant. Plant dry weight is highly correlated with RRT; it increases linearly as RRT increases.


2018 ◽  
Vol 15 (2) ◽  
pp. 177-192
Author(s):  
RR Saha ◽  
A Hannan ◽  
A Nessa ◽  
MA Malek ◽  
MR Islam

An experiment on hundred wheat genotypes under different levels of osmotic stress was carried out during 2014 to select the genotype(s) tolerant to drought at germination and early seedling stage. Different levels of osmotic stress were imposed by using polyethylene glycol (PEG). Three osmotic stress levels viz. control (distilled water), 15% PEG solution and 25% PEG solution were used. Among the 100 genotypes the rate of germination percentage, final germination (%), root and shoot dry weight, amount of respiration and vigour index under PEG treatment was found significantly lower than that of control condition. Compared to control condition relative decrease in rate of germination, final germination, amount of respiration and vigour index among the wheat genotypes were found more at 25% PEG than that of 15% PEG treatment. However, the seed metabolic efficiency was significantly higher in wheat genotypes under both 15% PEG and 25% PEG treatment compared to the control condition. A significant positive correlation exists between the important growth parameters like rate of germination (%), final germination (%), shoot dry weight, root dry weight and vigour index. On the basis of these physiological traits against osmotic stress, nine genotypes of wheat such as BD-480, BD-498, BD- 501, BD-513, BD-514, BD-519, BD-592, BD-618 and BD- 633 were selected as drought tolerant.SAARC J. Agri., 15(2): 177-192 (2017)


1991 ◽  
Vol 5 (4) ◽  
pp. 805-810 ◽  
Author(s):  
Michael J. Horak ◽  
Loyd M. Wax

Growth and development of bigroot morningglory was observed and quantified. Emergence occurred 75 ± 5 growing degree days (GDD) after seeding. Flower and seed production began 630 ± 20 GDD after emergence and continued until the first frost killed the shoots. Seedlings needed approximately 460 GDD of growth to become perennial. In the second year of growth, plants emerged in early May and flowered within 425 ± 50 GDD. Shoot dry weight accumulation in first-year plants was 3.5 g for the first 600 GDD after which a fifteenfold increase in dry weight occurred. Root growth followed the same pattern, however the large increase in dry weight occurred approximately 300 GDD later than that of the shoots. The root:shoot ratio was 0.2 to 0.3 for the first 900 GDD and increased to greater than 1.0 by the final harvest.


HortScience ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Ryan M. Warner

Flowering and morphology of four Petunia Juss. spp. [P. axillaris (Lam.) Britton et al., P. exserta Stehmann, P. integrifolia (Hook.) Schinz & Thell., and P. ×hybrida Vilm.] were evaluated in response to photoperiod and temperature. Photoperiod responses were evaluated under 9-h short days (SD), 9-h photoperiod plus 4-h night-interruption lighting (NI), or a 16-h photoperiod supplemented with high-pressure sodium lamps (16-h HPS). All species flowered earlier under NI than SD and were classified as facultative (quantitative) long-day plants. Increasing the daily light integral within long-day treatments increased flower bud number for P. axillaris only. In a second experiment, crop timing and quality were evaluated in the temperature range of 14 to 26 °C under 16-h HPS. The rate of progress toward flowering for each species increased as temperature increased from 14 to 26 °C, suggesting the optimal temperature for development is at least 26 °C. The calculated base temperature for progress to flowering varied from 0.1 °C for P. exserta to 5.3 °C for P. integrifolia. Flowering of P. axillaris and P. integrifolia was delayed developmentally (i.e., increased node number below the first flower) at 14 °C and 17 °C or less, respectively, compared with higher temperatures. Petunia axillaris and P. integrifolia flower bud numbers decreased as temperature increased, whereas P. ×hybrida flower bud number was similar at all temperatures. The differences in crop timing and quality traits observed for these species suggest that they may be useful sources of variability for petunia breeding programs.


Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 397-403
Author(s):  
David A. Wall

Greenhouse studies suggested that dog mustard was less competitive than wheat, but of similar competitiveness to flax. In field studies, dog mustard growth and development were markedly affected by crop competition. Competition from flax and wheat reduced dog mustard leaf area, shoot dry weight, plant height, and seed production compared with the weed grown on summer-fallow. Dog mustard was a prolific seed producer when grown in the absence of interspecific competition. On summer-fallow, dog mustard produced as many as 79,100 seeds plant−1when moisture was not a limiting factor. However, average seed production was 19,400 and 8000 seeds plant−1in 1994 and 1995, respectively.


1991 ◽  
Vol 69 (1) ◽  
pp. 226-228 ◽  
Author(s):  
Roy Turkington ◽  
Elena Klein

Cuttings of Trifolium repens were grown in pots without neighbours. When individual interconnected stolons from these cuttings were directed into adjacent pots so that daughter ramets were growing with different grass neighbours, these neighbouring grasses had dissimilar effects on leaf number, leaf size, percent branching of nodes, stolon length, and shoot dry weight. When the T. repens cuttings were grown in pots with neighbours, the effects of different grass neighbours on subsequent growth of stolons and ramets evened out. Key words: integration, clone, ramet, neighbour effects, Trifolium repens.


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