Refrigeration of the Root Zone to Delay Budbreak in Grapes

Grapes grown in West Texas are especially susceptible to freeze damage during spring deacclimation and budbreak. This experiment was undertaken to evaluate whether refrigeration of the root zone would delay budbreak in two grape cultivars, `Chardonnay' and `Cabernet Sauvignon'. The experiment was conducted under greenhouse conditions using 1-year-old grafted plants planted into containers in water bath chillers to cool the root zone. Three root-zone temperatures were maintained: 7.2 °C, 1.7 °C, and a nonchilled control. The experiment followed a randomized split plot, with main plots being temperatures and the sub-plots being genotype, and the experiment was repeated once. Evaluation of budbreak was performed on a daily basis. Other data collected included shoot dry weight and root dry weight with soil, water, and air temperatures recorded using type T thermocouples (copper-constantan) attached to a datalogger. The experiments indicated that budbreak could be delayed in both varieties by the refrigeration of the root zone by an average of 1 to 2 days when comparing the 1.7 °C treatment with the nonchilled control. The refrigerated treatments of `Chardonnay' also tended to show a prolonged budbreak over time. This finding may be significant since `Chardonnay' generally exhibits budbreak relatively early compared to other grape varieties and a prolonged budbreak may allow some buds to escape spring frost injury.

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GROWTH RESPONSE OF SNAPDRAGON ANTIRRHINUM MAJUS TO NIGHT AIR TEMPERATURES AND ELEVATED ROOT-ZONE TEMPERATURES

HortScience ◽

10.21273/hortsci.25.9.1160b ◽

1990 ◽

Vol 25 (9) ◽

pp. 1160b-1160

Author(s):

Khin San Wai ◽

S.E. Newman

Keyword(s):

Air Temperature ◽

Growth Response ◽

Root Zone ◽

Dry Weight ◽

Antirrhinum Majus ◽

Root Zone Temperature ◽

Shoot Dry Weight ◽

Air Temperatures ◽

Diffusive Resistance ◽

Zone Temperature

The response of Antirrhinum majus (snapdragon) cultivars (`Tampicoi' and `Rainier White') to night air temperatures (10C and 20C) and elevated root-zone temperature (26C and ambient) was studied. Height of plants grown with a heated root-zone were greater, compared to unheated at both night temperatures for both cultivars. Shoot dry weight of `Tampico' plants was reduced by heated root-zone temperature at 20C night air temperature. Raceme length was greater with heated root-zone temperature compared to unheated at 10C night air temperature. Days to flower were shorter with heated compared to unheated root-zone at both night air temperatures for both cultivars. Stomatal diffusive resistance was greater on plants with unheated compared to heated root-zone temperature at 10C night air temperature for `Rainier White'.

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The relationship between multiple leaders and mechanical and frost damage to the apical meristem of Scots pine seedlings

Canadian Journal of Forest Research ◽

10.1139/x90-041 ◽

1990 ◽

Vol 20 (3) ◽

pp. 280-284 ◽

Cited By ~ 7

Author(s):

Jarmo K. Holopainen

Keyword(s):

Scots Pine ◽

Apical Meristem ◽

Dry Weight ◽

Frost Damage ◽

Night Temperature ◽

Shoot Dry Weight ◽

Frost Injury ◽

Pine Seedlings ◽

Before And After ◽

Multiple Leaders

The responses of young Scots pine seedlings to mechanical apical meristem damage before and after 4 nights exposure to minimum night temperatures of −2.2 and −6.7 °C in controlled environment growth chambers were compared with control seedlings that were subjected or not to apical meristem damage and exposed to a minimum night temperature of 12 °C. The feeding damage caused by Lygus bugs was simulated by piercing the apical meristem of young pine seedlings with a hypodermic syringe needle and injecting a small drop of distilled water into the wound. At −6.7 °C increased numbers of dead seedlings were found. The proportion of seedlings with multiple leaders greatly increased after piercing, and about half of the seedlings subjected to the apical meristem damage had multiple leaders. The proportion of seedlings with multiple leaders and the number of leader shoots per seedling did not differ among seedlings subjected to apical meristem damage before or after the frost exposure. Short and twisted primary needles occurred in the basal parts of the new shoots in the seedlings with multiple leaders. Seedlings with necrotic needles were most often found after exposure to the night temperature of −6.7 °C. Shoot dry weight and length were significantly lower in seedlings subjected to apical meristem damage after frost exposure than in seedlings subjected to apical meristem damage before frost exposure or to no frost exposure. The results suggest that an increased reduction in growth is to be expected if Lygus bug attacks occur on pine seedlings that already suffer from frost injury.

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Air and Water Temperature Effects on Growth of Lettuce in a Hydroponic System

HortScience ◽

10.21273/hortsci.31.4.586b ◽

1996 ◽

Vol 31 (4) ◽

pp. 586b-586

Author(s):

Helen Thompson ◽

Robert Langhans

Keyword(s):

Crop Production ◽

Root Zone ◽

Dry Weight ◽

Root Zone Temperature ◽

Hydroponic System ◽

Air Temperatures ◽

Control Growth ◽

Water Plants ◽

Final Harvest ◽

Zone Temperature

This research explored cool crop production in various climate zones using CEA facilities and hydroponics ponds to control growth rate and quality through root zone temperature control. The precise controls were used to vary air and water temperatures to study the temperature gradient between root and shoot zones. Effect of this gradient was measured by growth rates and final harvest dry weights. Lactuca sativa L. cv. Ostinata seedlings were germinated and grown 11 days in a growth chamber and moved to greenhouse ponds. Air temperatures chosen were 17, 24, and 31°C. These were constant for the 24 days that lettuce grew in the ponds with a 5°C decrease for 14 hours. during the night. Water temperatures of the three ponds in the greenhouse were set and maintained at 17, 24, and 31°C. Maximum final harvest weights were obtained at 24°C air/water 24°C. Final weights for the 17 and 31°C water setpoint were comparable at 24°C air. The 31 °C air /water inhibited quality and final dry weight, while 17 and 24°C water produced equivalent dry weights at 31°C air. At 31°C air heads were tighter at 17 than at 24°C, and loose at 31°C. At air 17 °C maximum weight was at 24°C water and minimum at 31°C water. At 17°C air, the 24°C water plants were of good quality, with thicker leaves but visibly smaller than the 31°C water crop. Significant differences in harvest dry weights were shown at each 7-day harvest beginning on day 14, due to both air and water setpoint factors and there was significant interaction between them.

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Comparison of Growth and Alkalinity-induced Responses in Two Cultivars of Hibiscus (Hibiscus rosa-sinensis L.)

HortScience ◽

10.21273/hortsci.41.7.1704 ◽

2006 ◽

Vol 41 (7) ◽

pp. 1704-1708 ◽

Cited By ~ 4

Author(s):

Luis Alonso Valdez-Aguilar ◽

David William Reed

Keyword(s):

Root Zone ◽

Reductase Activity ◽

Dry Weight ◽

Hydroponic Culture ◽

Root Mass ◽

Shoot Dry Weight ◽

Hibiscus Rosa Sinensis ◽

Growing Medium ◽

Ph Increase ◽

Shoot Mass

Response to alkalinity was evaluated in two hibiscus cultivars, Bimini Breeze and Carolina Breeze, grown in a soilless growing medium and in hydroponic culture. For soilless growing medium, plants were potted in a sphagnum peat–perlite-based substrate and irrigated with solutions containing 0 to 10 mm NaHCO3 for 12 weeks. In hydroponic culture, bare-rooted plants were transferred to a 9-L tray containing a Hoagland's nutrient solution prepared with NaHCO3 at the concentrations previously indicated. In soilless growing medium, shoot dry weight was minimally affected by NaHCO3 concentration for `Bimini Breeze', but `Carolina Breeze' exhibited a significant decrease in shoot mass with increasing NaHCO3 concentration. In hydroponic culture, increasing concentration of NaHCO3 induced a decrease in shoot and root mass in both cultivars, but root mass decrease was more pronounced in `Bimini Breeze'. In soilless growing medium, increasing the concentration of NaHCO3 caused an increase in growing medium pH. The pH increase was less pronounced for `Bimini Breeze' than for `Carolina Breeze', indicating a higher capacity for root zone acidification by `Bimini Breeze'. Newly developed leaves of both cultivars showed increasing chlorosis with increasing NaHCO3 concentration. However, `Bimini Breeze' was more tolerant because, according to regression models, 5.7 mm NaHCO3 would be required to reduce chlorophyll levels by 10%, compared with 2.2 mm for `Carolina Breeze', when grown in soilless medium. Fe reductase activity decreased when `Carolina Breeze' plants were grown in 5 mm NaHCO3. However, in `Bimini Breeze', Fe reductase activity was enhanced. These observations indicate that the increased tolerance of `Bimini Breeze' to increasing alkalinity is the result of enhanced Fe reductase activity and increased acidification of the root zone.

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Crabapple and Lilac Growth and Root-zone Temperatures in Northern Nursery Production Systems

HortScience ◽

10.21273/hortsci.45.1.30 ◽

2010 ◽

Vol 45 (1) ◽

pp. 30-35 ◽

Cited By ~ 3

Author(s):

Catherine A. Neal

Keyword(s):

Production Systems ◽

Root Zone ◽

Dry Weight ◽

Plastic Container ◽

Shoot Dry Weight ◽

Common Lilac ◽

Ground System ◽

Nursery Production ◽

Landscape Establishment ◽

Shoot Mass

Crabapple (Malus ‘Donald Wyman’) and common lilac (Syringa vulgaris ‘Monge’) were grown from liners to marketable size in five production systems: field-grown, plastic container, pot-in-pot (PiP), bag-in-pot (BiP), and above-ground system (AGS). The objectives were to compare growth in modified container systems, which could potentially eliminate overwintering requirements in northern production nurseries and to compare the effects on tree root growth during landscape establishment. There were no significant differences in crabapple root or shoot mass after two seasons except PiP dry root weights exceeded field-grown trees. For lilacs, there were significant differences in growth and shoot dry weight with field-grown and PiP plants being largest. PiP root-zone temperatures (RZTs) were similar to field-grown RZTs. Container, BiP, and AGS systems all exceeded lethal high and low RZT thresholds, resulting in root damage. Five trees from each treatment were transplanted into a low-maintenance landscape and dug up 3 years later. There were no significant differences in top growth, but the effects of the production systems were evident in the root architecture. BiP and field-grown trees had fewest root defects and the greatest number of roots extending into the landscape soil.

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(82) Turf Species Affect Establishment and Growth of Cercis canadensis and Carya illinoiensis

HortScience ◽

10.21273/hortsci.40.4.1041b ◽

2005 ◽

Vol 40 (4) ◽

pp. 1041B-1041

Author(s):

Jason J. Griffin ◽

William R. Reid ◽

Dale Bremer

Keyword(s):

Leaf Area ◽

Tall Fescue ◽

Water Conservation ◽

Resource Competition ◽

Root Zone ◽

Warm Season ◽

Growth Parameter ◽

Dry Weight ◽

Root Dry Weight ◽

Shoot Dry Weight

Successful establishment and growth of newly planted trees in the landscape is dependent on many factors. Weed pressure and water conservation are typically achieved with either organic mulches or chemical herbicides applied over the root ball of the newly planted tree. In the landscape, eliminating turfgrass from the root zone of trees may be more complicated than resource competition. Studies have shown that tall fescue (Festucaarundinaceae Schreb.) has allelopathic properties on pecan trees [Caryaillinoiensis (Wangenh.) K. Koch]. Well-manicured tall fescue turf in the landscape may have negative effects on the establishment and growth of landscape trees as well. A study was designed to examine the effects of popular turfgrasses on the growth of newly planted pecan and redbud (Cerciscanadensis L.). Results demonstrate that the presence of turfgrass over the root zone of trees negatively impacts tree growth. Through two growing seasons, every growth parameter measured on redbuds (caliper, height, shoot growth, shoot dry weight, root dry weight, leaf area, and leaf weight) was significantly reduced by the presence of turf. However, the warm season bermudagrass [Cynodondactylon (L.) Pers.] was less inhibitied than the cool season grasses. The affects of turfgrass on pecan growth was less significant; however, caliper, leaf area, and root dry weight were significantly reduced when grown with turf.

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Temperature Effects on Growth of Impatiens Plug Seedlings in Controlled Environments

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.117.2.209 ◽

1992 ◽

Vol 117 (2) ◽

pp. 209-215 ◽

Cited By ~ 3

Author(s):

David R. Dreesen ◽

Robert W. Langhans

Keyword(s):

Leaf Area ◽

Growth Period ◽

Dry Weight ◽

Photon Flux ◽

Initial Growth ◽

Growth Responses ◽

Shoot Height ◽

Seedling Age ◽

Shoot Dry Weight ◽

Air Temperatures

The objective of this study was to determine the dry weight, height, and leaf area growth responses of impatiens (Impatiens walerana Hook. f.) plug seedlings to air temperatures ranging from 18 to 29C. The conditions maintained in the controlled-environment growth rooms (CEGR) were ambient C02 levels, 24-h lighting, and photosynthetic photon flux (PPF) ranging from ≈215; to 335 μmol·m-2·s-1. Mean daily temperatures of the plug medium ranged from 19.6 to 27.7C. At the higher PPF level, shoot dry weight decreased at plug medium temperatures (PMT) > 25C; at lower PPF levels (<300 μmol·m-2·s-1), shoot dry weight continued to increase with PMT > 25C. The mean relative growth rate (MRGR) of shoot dry weight was positively correlated with PMT during the initial growth period (up to 14 days from sowing) and was negatively correlated thereafter. The maximum MRGR was predicted to occur at 11.7 days from sowing for a PMT of 19.6C, at 10.8 days for a PMT of 21.6C, and at 9.7 days for a PMT of 23.6C. Linear regression coefficients of shoot height as a function of PMT were substantially higher for seedlings grown at lower PPF than those for seedlings from the highest PPF level. Seedling leaf area consistently increased with increasing temperature. Net assimilation rate (NAR) decreased with increasing seedling age NAR increased with increasing PPF. A decrease in NAR was apparent at 29C relative to values at the lower temperatures. Leaf area ratio (LAR) declined with increasing seedling age and PPF; a quadratic relationship of LAR as a function of PMT indicates a minimum LAR at 22.5C. The seedlings grown at 29C were excessively tall, had thin succulent leaves, and were judged unacceptable for shipping and transplanting. Maximum quality indices (i.e., dry weight per height) were found at PMT of 24.3 to 25.OC for 10- to 14-day-old seedlings and at PMT of 23.0 to 24.OC for 16- to 20-day-old seedlings.

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Role of Gibberellin A4 and Gibberellin Biosynthesis Inhibitors on Flowering and Stem Elongation in Petunia under Modified Light Environments

HortScience ◽

10.21273/hortsci.40.1.134 ◽

2005 ◽

Vol 40 (1) ◽

pp. 134-137 ◽

Cited By ~ 5

Author(s):

T.A. Cerny-Koenig ◽

J.E. Faust ◽

N.C. Rajapakse

Keyword(s):

Stem Elongation ◽

Dry Weight ◽

Gibberellin Biosynthesis ◽

Shoot Dry Weight ◽

Long Day ◽

Air Temperatures ◽

Biosynthesis Inhibitors ◽

Growing Environment ◽

Ga Biosynthesis

In our previous experiments, greenhouse films that selectively remove far-red (FR) light from the growing environment reduced the stem elongation but delayed anthesis of long day plants. In the present research we investigated if the application of gibberellin A4 and gibberellin (GA) biosynthesis inhibitors could overcome the delay in anthesis of petunia (Petunia ×hybrida Vilm.-Andr.), a quantitative long-day plant, under a FR light deficient environment. The GA biosynthesis inhibitors prohexadione-Ca and exo-C-16,17-dihydro GA5 (GA5) were used because of their ability to prevent catabolism of active GAs. Anthesis and stem elongation were investigated under control, red (R; 600 to 700 nm) and FR (700 to 800 nm) light-absorbing (AR and AFR) films. The R:FR ratios of control, AR, and AFR films were 1.03, 0.71, and 1.51, respectively. Air temperatures among treatment chambers were not different. AR film did not affect anthesis or stem elongation, but AFR film reduced stem elongation and delayed anthesis by 12 days. Exogenous application of GA5 had no effect on stem elongation, shoot dry weight or days to anthesis at any concentration (0 to 100 mg·L-1) tested under control, AR, or AFR films. Anthesis was delayed with increasing concentration (0 to 200 mg·L-1) of prohexadione-Ca under all treatments. Prohexadione-Ca at 200 mg·L-1 delayed anthesis by 11 and 7 days under the control and AFR film, respectively, suggesting an interaction between light quality and prohexadione-Ca treatment. Exogenous GA4 accelerated anthesis under both films but the promotion was greater under the AFR films. However, GA4 treatment increased stem elongation and the increase in stem elongation was greater under the AFR film. Addition of GA5 to GA4 had no added effect on flowering and failed to reduce stem elongation. Therefore, GA or GA inhibitors are not suitable for flower promotion under AFR films.

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SPUNBONDED FABRIC COVERS ALTER EARLY SEASON GROWTH AND FRUIT SET IN CRANBERRY

HortScience ◽

10.21273/hortsci.25.9.1105c ◽

1990 ◽

Vol 25 (9) ◽

pp. 1105c-1105

Author(s):

Elden J. Stang ◽

John Klueh

Keyword(s):

Fruit Set ◽

Leaf Tissue ◽

Leaf Size ◽

Dry Weight ◽

Vaccinium Macrocarpon ◽

Anthocyanin Content ◽

Shoot Dry Weight ◽

Air Temperatures ◽

Polypropylene Fabric ◽

Soil Temperatures

Spunbonded polypropylene fabric covers were applied over mature `Searles' cranberry (Vaccinium macrocarpon Ait. in the field during dormancy in 1989. Covers were selectively removed at 3 week intervals in April, May and early June after onset of growth. Plant canopy air temperatures under fabric were 5 to 6C higher than in exposed controls. Temperature differences up to 17C were measured in early June. Soil temperatures did not differ from the control until late May. Earlier greening of leaf tissue resulted in increased photosynthetic rates earlier in the growing season under fabric covers. Subsequent shoot dry weight was increased 5%; leaf size was not affected. A trend to increased fruit set (4 to 6%) with fabric cover treatments was observed when covers were applied for 6 or 9 weeks. Total fruit yield and anthocyanin content were not appreciably influenced by fabric covers.

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Velvet Bentgrass and Creeping Bentgrass Growth, Rooting, and Quality with Different Root Zone Media and Fertility Regimes

HortScience ◽

10.21273/hortsci.47.2.205 ◽

2012 ◽

Vol 47 (2) ◽

pp. 205-211 ◽

Cited By ~ 1

Author(s):

John Watson ◽

François Hébert ◽

Eric M. Lyons ◽

Theo Blom ◽

Katerina S. Jordan

Keyword(s):

Root Zone ◽

Creeping Bentgrass ◽

Dry Weight ◽

Root Production ◽

Nitrogen Rate ◽

Root Zones ◽

Shoot Dry Weight ◽

Turfgrass Quality ◽

Nitrogen Rates ◽

Agrostis Canina

Two complementary greenhouse studies were conducted to examine the effects of different root zones and fertilization regimes on ‘SR7200' velvet bentgrass (Agrostis canina L.) and L-93 creeping bentgrass (Agrostis stolonifera L.). In the first study, in which only velvet bentgrass was studied, peat content in the root zone mixture contributed significantly to initial establishment of this species and high seeding rates increased cumulative shoot dry weight early in establishment but became less significant as the turfgrass matured. Higher phosphorus rates contributed to increased cumulative shoot dry weight over the first 4 weeks of the experiment. Nitrogen rate was the most significant factor positively affecting both cumulative shoot dry weight and turfgrass quality. In the second experiment with both velvet bentgrass and creeping bentgrass, nitrogen rate significantly increased turfgrass quality when measured at Week 5, halfway through the experiment. Over time, however, turf growth and quality were negatively impacted in both species with increasing nitrogen rates. Root zone composition had a significant effect on initial establishment of both bentgrasses with greater peat content leading to higher quality early on. Cumulative shoot dry weight increased with increasing nitrogen rate but at higher rates, there was a concomitant decrease in root production.

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