scholarly journals Supraoptimal Root-zone Temperatures Affect Dahlia Growth and Development

2021 ◽  
pp. 1-12
Author(s):  
Karen K. Schneck ◽  
Cheryl R. Boyer ◽  
Chad T. Miller
Keyword(s):  
Growth And Development ◽  
Root Zone ◽  
Growth Parameters ◽  
Hot Water ◽  
Water Bath ◽  
Plant Responses ◽  
Greenhouse Production ◽  
Total Crop ◽  
Greenhouse Growers ◽  
Root Quality

Dahlia (Dahlia ×hybrida) is an important floriculture crop that has gained popularity in recent years. Greenhouse growers have recently reported a phenomenon known as “dahlia decline,” that can affect potted dahlias in greenhouse production. The crop exhibits graying foliage, root decline, and plant death, and the phenomenon has reportedly caused partial or total crop loss and has no known initiating factor. We hypothesized that plant exposure to supraoptimal root-zone temperatures (RZTs) during production may decrease dahlia root quality, especially above 40 °C and could initiate dahlia decline. Because there is a lack of understanding on how supraoptimal RZT may impact dahlia growth and development, experiments were conducted to evaluate the effects of supraoptimal RZTs on seven dahlia cultivars in Spring 2019 and 2020. Dahlias were grown for 4 to 5 weeks in the greenhouse and then root zones were exposed to ≈22 (control), 35, 40, 45, or 50 °C using a water bath. Root quality was rated before treatment and rated weekly after the hot water bath treatment, along with vegetative growth parameters for 4 weeks. In both years, significant decline in root ratings were observed. ‘XXL Veracruz’ and ‘XXL Sunset’ average root ratings decreased after a 45 and 50 °C treatments in year 2 and both cultivars demonstrated increased root rating averages by 3 weeks after treatment. Cultivars exhibited a significant increase in root rating in the final observations when compared with root ratings taken 1 week posttreatment even if the initial decline after treatment was not significant. Overall plant height was significantly impacted, resulting in shorter heights in both years for all cultivars as treatment temperatures increased to 50 °C in comparison with the control and 35 °C, and a few cultivars exhibited significantly shorter height at 40 and 45 °C. Ultimately, our research did not show typical plant responses that were consistent with reported dahlia decline, but we were better able to characterize dahlia response to supraoptimal RZT.

Growth of Dracaena marginata and Spathiphyllum ‘Petite’ in Sphagnum Peat- and Coconut Coir Dust-based Growing Media

1999 ◽  
Vol 17 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Robert H. Stamps ◽  
Michael R. Evans
Keyword(s):  
Growth Parameters ◽  
Cocos Nucifera ◽  
Greenhouse Production ◽  
Growing Media ◽  
Sphagnum Peat ◽  
Affected Plant ◽  
Coir Dust ◽  
Media Component ◽  
The Media ◽  
Cocos Nucifera L

Abstract A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for greenhouse production of Dracaena marginata Bak. and Spathiphyllum Schott ‘Petite’. Three soilless foliage plant growing mixes (Cornell, Hybrid, University of Florida #2 [UF-2]) were prepared using either SP or CD and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (% by vol): Cornell = 50 CD or SP:25 V:25 P, Hybrid = 40 CD or SP:30 V:30 PB, UF-2 = 50 CD or SP: 50 PB. Dracaena root growth was not affected by treatments but there were significant mix × media component interactions that affected plant top growth parameters. In general, the growth and quality of D. marginata were reduced by using CD in Cornell, had no effect in Hybrid, and increased in UF-2. S. ‘Petite’ grew equally well in all growing mixes regardless of whether CD or SP was used; however, plants grew more in Cornell and Hybrid than in UF-2. S. ‘Petite’ roots, which were infested with Cylindrocladium spathiphylli, had higher grades when grown in CD than when the media contained SP.

Commodity Heating Medium and Mexican Fruit Fly Mortality

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 533e-533
Author(s):  
Krista C. Shellie
Keyword(s):  
Carbon Dioxide ◽  
Variable Temperature ◽  
Larval Mortality ◽  
Fruit Fly ◽  
Hot Water ◽  
Water Bath ◽  
Controlled Atmosphere ◽  
Mexican Fruit Fly ◽  
Temperature Water ◽  
Heating Medium

The objective of this research was to investigate whether the medium used to transfer heat to a commodity influenced the mortality of Mexican fruit fly larvae. A similar 2-h heat dose was delivered to grapefruit via immersion in a variable temperature water bath or via exposure to a rapidly circulating gas. The concentration of oxygen and carbon dioxide inside the grapefruit was analyzed at 30-min intervals and grapefruit center temperatures recorded every 60 s during heating. The mortality of larvae located inside grapefruit during heating in a controlled atmosphere or in hot water was significantly higher than that of larvae located inside grapefruit heated in air. The internal atmosphere of grapefruit heated in a controlled atmosphere or in hot water contained significantly higher levels of carbon dioxide and lower levels of oxygen than grapefruit heated in air. Larval mortality was compared after larvae were heated in media by rapidly circulating air or by an atmosphere containing 4 kPa of oxygen and 18 kPa of carbon dioxide to evaluate whether the altered atmosphere or a heat-induced fruit metabolite was responsible for enhanced mortality. The significantly higher mortality of larvae heated in media in the presence of an altered atmosphere suggested that the altered atmosphere enhanced larval mortality. Results from this research suggest that reducing oxygen and or increasing the level of carbon dioxide during heating can enhance mortality of the Mexican fruit fly and potentially reduce the heat dose required for quarantine security.

Hydroponic Greenhouse Production of Fresh-market Basil in Colorado

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 480f-481
Author(s):  
C. Elizabeth Succop ◽  
Steven E. Newman
Keyword(s):  
Nutrient Solution ◽  
Root Zone ◽  
Organic Fertilizer ◽  
Fresh Weight ◽  
Organic Solution ◽  
Fresh Market ◽  
Greenhouse Production ◽  
Raised Bed ◽  
Certified Organic ◽  
Organic Produce

Fresh-market basil has become a viable greenhouse commodity in Colorado. Marketing pressures and profit advantages also encourage the production of certified organic produce. The research objectives were to determine the length of time basil plants were productive in the greenhouse and to compare the production of fresh-market basil grown with three root zone systems and two fertilizer treatments. The three systems were hydroponic rockwool slab culture, hydroponic perlite raised bed culture, and hydroponic peat/perlite/compost bag culture. The two types of hydroponic fertilizer treatments were a salt-based formulated nutrient solution and an organic solution consisting of fermented poultry compost, hydrolized fish emulsion, and soluble kelp. The plants were harvested once per week for fresh weight determination. The results from the two runs show greater productivity for the plants in the perlite system as well as the bag mix system when fertilized with the organic fertilizer compared to salt-based fertilizer. However, productivity of the plants in the rockwool system was greater with the salt-based treatment compared to the organic treatment.

Plastic Mulch Color Effects on Light Micro-environment and Watermelon Plant Growth

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 474d-474
Author(s):  
N.K. Damayanthi Ranwala ◽  
Dennis R. Decoteau
Keyword(s):  
Plant Growth ◽  
Light Transmission ◽  
Root Zone ◽  
Dry Mass ◽  
Plant Responses ◽  
Plastic Mulch ◽  
Plant Parts ◽  
Reflected Light ◽  
Total Light ◽  
Dry Mass Partitioning

This study was conducted to evaluate the spectral properties of various colored plastic color mulches and to determine the effects of upwardly reflected light from the mulch surfaces on watermelon plant growth when differences in root zone temperatures are minimized. Two-week-old watermelon plants were grown with black mulch, red-painted mulch, SRM-Red mulch (Sonoco, Inc., Harstville, S.C.), and white mulch. Total light reflection (58 μmol·m–2·s–1 in 400–700 nm) and red: far-red (R:FR = 0.44) of reflected light were lower in black mulch and highest in white mulch (634 and 0.92, respectively). Both black mulch and white mulch had same blue:red (B:R = 0.6) while white mulch had higher B:FR (0.58) in reflected light compared to black mulch (0.26). Reflective properties of red mulches were somewhat similar, and R:FR, B:R, and B:FR were 0.8, 0.2, and 0.18, respectively. However, SRM-Red mulch had highest total light (355 μmol·m–2·s–1 in 400–700 nm) transmission through the mulch, and R:FR, B:R, and B:FR were 0.84, 0.28, and 0.23, respectively. Light transmission through the other mulches was nonsignificant. Watermelon plants grown with black mulch and red mulches had higher internode lengths compared to white mulch after 20 days. Further, plants grown under black had significant higher petiole elongation accompanied with higher dry mass partitioning to petioles, and lower partitioning to roots, stems, and leaves. There was no effects of surface mulch color on total plant dry mass or photosynthesis although plants with black had higher transpiration rate. This suggests the differential regulation of dry mass partitioning among plant parts due to mulch color. The similar plant responses with black mulch and white mulch to plants treated with FR or R light at the end of photoperiod implies the involvement of phytochrome regulation of growth due to mulch surface color.

Application Research of Neural Expert System on Tree Growth Model

2014 ◽  
Vol 513-517 ◽  
pp. 3728-3731
Author(s):  
Wen Qing Zhang
Keyword(s):  
Expert System ◽  
Tree Growth ◽  
Growth And Development ◽  
Production Management ◽  
Environmental Control ◽  
Growth Parameters ◽  
Growth Models ◽  
Growth Management ◽  
Management Decision ◽  
Factors Affecting

In order to simulate growth and development process of tree, then provide services for production management and scientific research, all kinds of tree growth models are constructed. The paper firstly considers a variety of factors affecting the growth and development of tree, then studies artificial intelligence knowledge such as neural network and expert system, uses the neural expert system to solve the acquisition and management of tree growth parameters, and design and develop tree growth management and expert system based on growth models, the models combine morphogenesis model of tree and knowledge model to provide comprehensive environmental control and management decision-making. Practice has indicated that the growth models of tree can reflect the growth of trees under different physiological and ecological conditions, and visual effect is very good.

scholarly journals Physiological Implications of Hydrogen Sulfide in Plants: Pleasant Exploration behind Its Unpleasant Odour

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zhuping Jin ◽  
Yanxi Pei
Keyword(s):  
Hydrogen Sulfide ◽  
Growth And Development ◽  
Defense Responses ◽  
Plant Responses ◽  
Plant Growth And Development ◽  
Systematic Classification ◽  
Physiological Processes ◽  
Overwhelming Evidence

Recently, overwhelming evidence has proven that hydrogen sulfide (H2S), which was identified as a gasotransmitter in animals, plays important roles in diverse physiological processes in plants as well. With the discovery and systematic classification of the enzymes producing H2Sin vivo, a better understanding of the mechanisms by which H2S influences plant responses to various stimuli was reached. There are many functions of H2S, including the modulation of defense responses and plant growth and development, as well as the regulation of senescence and maturation. Additionally, mounting evidence indicates that H2S signaling interacts with plant hormones, hydrogen peroxide, nitric oxide, carbon monoxide, and other molecules in signaling pathways.

scholarly journals Comparative Study of Different Irrigation System for Cotton Crop in District Rahim Yar Khan, Punjab, Pakistan

2020 ◽  
Vol 8 (2) ◽  
pp. 131-138
Author(s):  
Muhammad Yousaf Ali
Keyword(s):  
Root Zone ◽  
Growth Parameters ◽  
Irrigation System ◽  
Plant Root ◽  
Maximum Yield ◽  
Sprinkler Irrigation ◽  
Water Saving ◽  
Limiting Factors ◽  
Water Losses ◽  
Day By Day

The biggest responsibility of agriculture department is to produce food and cloth for huge population using the resource getting limited day by day. Water scarcity is most threatening among these limiting factors. New techniques are being developed day by day to utilize the water efficiently. Application of water only in the plant root zone will be one of the water saving technique to grow crops. This will control the losses due to evaporation and leaching. Irrigation to soil does not control the climate variables and precipitation cannot be substituted to irrigation. Sprinkler irrigation could be one of the way to utilize the water efficiently by in time application and reducing the losses of leaching and evaporation along with amelioration of micro climate of the crop. Canals and tube well water is conventionally given to crop through flood irrigation. These fields are in direct threat of evaporation and leaching resulting in excess water losses and damaging the soil quality. The study was designed taking cotton as experimental crop to calculate comparisons in plant growth parameters and yields along with water saving ability of different irrigation system. Maximum yield was obtained from sprinkler irrigation and water was saved under drip irrigation system.

scholarly journals Effect of salicylic acid on pre-transplant acclimatization of native tomato populations

2018 ◽  
Vol 36 (4) ◽  
pp. 480-485
Author(s):  
Wilberth A Poot-Poot ◽  
Rafael Delgado-Martínez ◽  
Sergio Castro-Nava ◽  
Ma Teresa Segura-Martínez ◽  
Alejandro Carreón-Pérez ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Growth And Development ◽  
Growth Parameters ◽  
Field Capacity ◽  
Dry Weight ◽  
Growth Conditions ◽  
Peat Moss ◽  
Hypocotyl Length ◽  
Cell Processes ◽  
Recorded Data

ABSTRACT The aim of this study was to evaluate the effect of salicylic acid (SA) application on pre-transplant acclimatization of native populations of tomato. SA is a growth regulator that modifies plant growth and development by inducing changes in cell processes, physiology and morphology. Five populations of native tomato were sown in polystyrene trays. Peat moss was used as substrate and plants were maintained at field capacity continuously. After emergence, seedlings were applied during three weeks with different concentration of SA (0.0, 0.01, 0.1, 0.5 and 1.0 μM). A completely random experimental design was used with five replications per treatment. The growth parameters evaluated were height, stem diameter, number of leaves, hypocotyl length, shoot fresh and dry weight (leaves and stem), and root length and fresh and dry weight. An analysis of variance was carried out, and means were compared with the Tukey test (5%) using SAS statistical software. The recorded data show that pre-transplant seedlings of each of the evaluated populations responded significantly (P=0.01) to the SA treatments. Also, the comparison of means of each of the factors under study showed positive changes. With the concentrations of 0.5 and 0.1 μM SA, higher values of the studied variables were obtained than with the concentrations 0.01 and 1.0 μM SA. The native tomato populations sprayed with SA at concentrations of 0.5 and 0.1 μM responded positively in terms of seedling growth and development. Based on these findings, SA treatments can help acclimatize and present better growth conditions to the seedlings before being transplanted.

Contributions to the Analysis of Rubber. I. Determination of the Water-Soluble Components of Rubber

1937 ◽  
Vol 10 (3) ◽  
pp. 574-583
Author(s):  
P. Dekker
Keyword(s):  
Acetic Acid ◽  
Acid Reflux ◽  
Water Soluble ◽  
Hot Water ◽  
Water Bath ◽  
Vulcanized Rubber ◽  
Magnesium Compounds ◽  
Calcium Compounds ◽  
Soluble Components

Abstract 1. It is shown that the methods which are ordinarily used for determining water-soluble substances in raw rubber give low results, and are quite useless for vulcanized rubber. 2. New analytical procedures are developed for determining the water-soluble substances in raw rubber and in vulcanized rubber. These procedures are carried out in the following manner. (a) Raw Rubber.—Heat 2 grams of rubber in 80 cc. of xylene and 5 cc. of acetic acid on a water bath until the rubber is completely dissolved, add 5 cc. of acetic acid and 10 cc. of water, heat for 3–4 hours on the water bath with frequent agitation, transfer to a distilling flask (rinsing the first flask with 50 cc. of hot water), distill the xylene with steam, filter the residual solution, evaporate the filtrate on a water bath; and dry at 100° C. (b) Vulcanized Rubber and Rubber Mixtures.—First extract the sample with acetone, heat 2 grams of the acetone-extracted sample with 80 cc. of xylene on a water bath, add 5 cc. of acetic acid, reflux the mixture on an oil bath, after complete dissolution add 5 cc. of acetic acid and 10 cc. of water, heat the solution for 2 hours on an oil bath at 110–120° C., distill the xylene, as in the determination with raw rubber, filter the residue, evaporate the filtrate to dryness, take up the residue in 50 cc. of water, pass a current of hydrogen sulfide through the solution for 10 minutes to precipitate zinc as sulfide, filter, evaporate the filtrate, and dry the residue at 100° C. 3. In the presence of calcium compounds, magnesium compounds, glue and textiles, the method gives false results. Modifications of the method are therefore recommended, whereby these substances are eliminated.

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