scholarly journals Effects of Three Hotcap Designs on Temperature and Tomato Transplant Development

HortScience ◽  
1993 ◽  
Vol 28 (9) ◽  
pp. 878-881
Author(s):  
G.E. Welbaum
Keyword(s):  
Solar Energy ◽  
Lycopersicon Esculentum ◽  
Growth Chamber ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Ripe Fruit ◽  
Air Temperatures ◽  
Cloudy Weather ◽  
Soil Temperatures ◽  
Opaque Plastic

Hotcaps are covers used to protect individual plants from suboptimal temperatures. Temperature, solar energy, photosynthetic photon flux (PPF), and tomato (Lycopersicon esculentum Mill.) transplant development were compared for three hotcap designs: 3.8-liter, opaque plastic jugs (PJs); 24-cm-tall wax paper (WP); and Wall-O-Water water-filled plastic teepees (PTs). The average solar energy inside the hotcaps was 57.3%, 67.6%, and 28.9% of full sun at midday and PPF was 44.7%, 49.7%, and 43.8% of full sun at midday for WP, PJs, and PTs, respectively. The rate of temperature decline in a growth chamber was fastest for PJs and slowest for PTs. In the field, air and soil temperatures inside hotcaps were higher than ambient during sunny periods and essentially the same during cloudy weather. The overall mean and mean maximum daily soil and air temperatures for all hotcaps were higher than ambient. PTs had the highest minimum daily soil and air temperatures—2.0 and 1.9C above ambient, respectively. The meantime to first ripe fruit was reduced by 10.7 days for PTs, 6.7 days for WP, and increased by 5 days for PJs compared to noncovered plants. Plants grown under hotcaps weighed less and produced fewer fruit on the first cluster. PJs could not maintain night air temperatures above ambient and were not effective hotcaps.

Effects of climate warming on canopy water dynamics of a boreal black spruce plantation

2011 ◽  
Vol 41 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Ingrid G. Van Herk ◽  
Stith T. Gower ◽  
Dustin R. Bronson ◽  
Myron S. Tanner
Keyword(s):  
Flux Density ◽  
Black Spruce ◽  
Photosynthetic Photon Flux Density ◽  
Water Dynamics ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Sap Flux ◽  
Photosynthetic Photon Flux ◽  
Entire Study ◽  
Soil Temperatures

The purpose of this study was to quantify the effects of climate change (in the form of elevated air and soil temperatures) on transpiration and sap flux rates of black spruce ( Picea mariana (Mill.) BSP). Five treatments were established in northern Manitoba, Canada, with the experimental design consisting of heated and control blocks. Air and soil temperatures were maintained approximately 5 °C above control temperatures using greenhouse chambers. Two of the chambers also included controls to maintain ambient vapor pressure difference (VPD). Sap flux (JS), was not significantly different among treatments in the May or July time periods. However, JS was significantly greater for heated VPD controlled trees than for trees in all other treatments when averaged over the entire study period. JS was positively correlated to photosynthetic photon flux density for all trees. Lower photosynthetic photon flux density in chamber treatments resulted in the creation of models used to estimate JS and canopy transpiration (EC) values that were used in the analysis. Average daily and cumulative growing season EC values were significantly greater for the heated VPD controlled treatments than for other treatments. The results from this study suggest that EC of boreal black spruce will increase if VPD remains unchanged while air temperatures increase.

scholarly journals 510 PB 260 COMPARISON OF FIELD AND SHADEHOUSE MICROCLIMATE FACTORS RELATED TO EVAPORATION AND CROP TRANSPIRATION

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 504e-504
Author(s):  
Robert H. Stamps
Keyword(s):  
Photon Flux ◽  
Pressure Gradients ◽  
Crop Canopy ◽  
Photosynthetic Photon Flux ◽  
Water Losses ◽  
Air Temperatures ◽  
Plant Water Use ◽  
Adjacent Field ◽  
Rumohra Adiantiformis ◽  
Incoming Light

Microenvironmental conditions in a shadehouse covered with shade fabric designed to exclude 70% of incoming light were monitored and compared to those in an adjacent field to quantify differences related to plant water use. Radiant flux density and photosynthetic, photon flux inside the shadehouse varied seasonally between about 18% to 28% of outside values. During the day, leaf and air temperatures around the crop canopy were generally lower and relative humidities higher inside the shadehouse than outside. Leaf-to-air vapor pressure gradients inside the shadehouse averaged about half those outside. Wind run inside was <10% of wind run outside. Differences between reference ET (ETo) values, calculated using Penman's equation), inside and outside the shadehouse were greatest during summer months. Outside evaporatory pan (Epan) water losses ranged from 205 mm in July to 95 mm in Nov. For the same months, Epan losses inside were about 80% lower. Monthly ETactual, as determined for Rumohra adiantiformis growing in lysimeters in the shadehouse, ranged from around 40% to 80% of inside Eo.

scholarly journals EFFECT OF LIGHT, CO2, AND SUCROSE CONCENTRATIONS ON THE IN VITRO GROWTH OF WHITE POTATO (SOLANUM TUBEROSUM L.)

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 696f-696
Author(s):  
N.C. Yorio ◽  
R.M. Wheeler ◽  
R.C. Weigel
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Tuberosum L ◽  
Dry Weight ◽  
Growth Chamber ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
White Potato ◽  
High Sucrose ◽  
Effect Of Light

Growth measurements of potato (Solanum tuberosum L.) cvs. Norland (NL), Denali (DN), and Kennebec (KN) were taken from 21-day-old plantlets grown in vitro. Studies were conducted in a growth chamber, with nodal explants grown in culture tubes with loose-fitted Magenta 2-way caps containing Murashige and Skoog salts with either 0, 1, 2 or 3% sucrose. The cultures received either 100 or 300 μmol m-2 s-1 photosynthetic photon flux (PPF), and the growth chamber was maintained at either 400 or 4000 μmol mol-1 CO2. All cvs. showed significant increases in growth on 0% sucrose media at 4000 μmol mol-1 CO2, indicating an autotrophic response. At 400 μmol mol-1 CO2, all cvs. showed an increase in total plantlet dry weight (DW) with increasing sucrose under both PPF levels. Within any sucrose treatment, the highest total DW for all cvs. resulted from 300 μmol m-2 s-1 PPF and 4000 μmol mol-1 CO2. At 4000 μmol mol-1 CO2, shoot DW declined with sucrose above 2% for DN and sucrose above 1% for NL at both PPF levels, suggesting that high sucrose levels may hinder growth when CO2 enrichment is used.

scholarly journals Effects of Air Temperature Regimes on Physiological Disorders and Floral Development of Tomato Seedlings Grown under Continuous Light

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1304-1306 ◽  
Author(s):  
Katsumi Ohyama ◽  
Yoshitaka Omura ◽  
Toyoki Kozai
Keyword(s):  
Air Temperature ◽  
Floral Development ◽  
Continuous Light ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Tomato Seedlings ◽  
Physiological Disorders ◽  
Air Temperatures ◽  
Temperature Regimes ◽  
Leaf Chlorosis

Providing continuous light (24-h photoperiod) at a relatively low photosynthetic photon flux (PPF) is one possible way to reduce both initial and operational costs for lighting and cooling during transplant production with an artificial light. However, physiological disorders (i.e., chlorosis and necrosis) are often observed in several species under continuous light with a constant temperature. The objective of this study was to find an effective air-temperature regime under the continuous light to avoid such physiological disorders, and simultaneously enhance floral development, using tomato [Lycopersicon esculentum Mill.] as a model. The seedlings with fully expanded cotyledons were grown for 15 d at a PPF of 150 μmol·m–2·s–1, a relative humidity of 70%, and a CO2 concentration of about 380 μmol·mol–1 (atmospheric standard). Leaf chlorosis was observed when the air temperature was constant regardless of average air temperature (16, 22,or 28 °C). Neither leaf chlorosis nor necrosis was observed when the air temperatures were alternated [periods of high (28 °C) and low (16 °C) air temperatures of 16/8, 12/12, and 8/16 h·d–1]. Faster floral development was observed in the seedlings grown at lower average air temperatures. These results indicated that physiological disorders of tomato seedlings grown under continuous light could be avoided, and at the same time floral development could be enhanced, by lowering the average air temperature through modification of the periods of high and low air temperatures.

scholarly journals CAN PLANTS DETECT SMALL DIFFERENCES IN IRRADIANCE OBTAINED BY VARYING THE REFLECTANCE PROPERTIES OF THE GROWTH CHAMBER WALLS?

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 656b-656
Author(s):  
Donald T. Krizek ◽  
Roman M. Mirecki ◽  
Alton L. Fleming
Keyword(s):  
Shoot Elongation ◽  
Growth Chamber ◽  
Photon Flux ◽  
Controlled Environment ◽  
Wall Surface ◽  
Photosynthetic Photon Flux ◽  
Fluorescent Lamps ◽  
Environment Study ◽  
Growth Chambers

A controlled-environment study was conducted in separate growth chambers with the wall surface covered either with white enamel paint (WEP) or polished aluminum (PA). `Williams' soybean were grown under 1500 mA cool white fluorescent lamps and internodes measured at 7, 14, and 21 days. Photosynthetic photon flux (PPF) levels in the center of each chamber were set at 320 μmol m-2 s-1 with a quantum sensor. Means ± SD for PPF levels in the WEP and PA chambers were 286 ± 28 and 307 ± 11 μmol m-2 s-1, respectively. This increase in mean PPF and decrease in variance of PPF in the PA chamber was reflected in: a) a decrease in hypocotyl, first internode, and total shoot elongation: and b) an increase in enlargement of the primary and the first trifoliolate leaves. These findings demonstrate that plants can detect small differences in irradiance within a growth chamber and suggest the advantages of using a highly polished wall surface to improve uniformity of irradiance and reduce variability in growth.

EFFECTS OF SOIL TEMPERATURE ON MANGANESE AVAILABILITY TO PLANTS GROWN ON AN ORGANIC SOIL

1985 ◽  
Vol 65 (4) ◽  
pp. 769-775 ◽  
Author(s):  
J. M. REID ◽  
G. J. RACZ
Keyword(s):  
Soil Temperature ◽  
Organic Soil ◽  
Growth Chamber ◽  
Leaf Stage ◽  
Plant Parts ◽  
Boot Stage ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Chamber Studies ◽  
Growth Chamber Studies

The effect of soil temperature on the availability of manganese to wheat (Triticum aestivum ’Neepawa’) and barley (Hordeum vulgare ’Conquest’) from an organic soil was studied in a controlled environment growth chamber. Wheat and barley plants were grown in cylindrical pots placed in temperature-controlled water baths with soil (root) temperatures maintained at 10, 15, 20 and 25 °C. Air temperatures were maintained at 20/13 °C for the day/night intervals, respectively. Aerial plant parts were harvested at the three- to four-leaf stage and at the boot stage. Dry matter yields of wheat and barley tended to be greatest at soil temperatures of 20 or 25 °C when harvested at the three- to four-leaf stage. In contrast, yields obtained at the boot stage were usually greatest at a soil temperature of 15 °C. Concentrations of manganese in shoots of wheat and barley at both stages of growth increased significantly when soil temperatures were increased from 10 to 25 °C.In a second study, MnSO4∙H2O was supplied to barley plants grown at the four different soil temperatures. The MnSO4 increased Mn concentrations in shoots harvested at the three- to four-leaf stage at all soil temperatures. In contrast, MnSO4 was ineffective in increasing Mn concentration in shoots harvested at the boot stage. In addition to the plant growth studies, soil samples were extracted with 0.005 M DTPA or 1.0 M ammonium acetate (NH4OAc) at the different temperatures. Extractable Mn increased with increasing soil temperature and amounts extracted closely reflected the increases in amounts of Mn utilized by the plants in the growth chamber studies. Key words: Soil temperature, manganese, organic soil, availability

scholarly journals Floral Ontogeny of Pelargonium ×domesticum

2000 ◽  
Vol 125 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Marietta Loehrlein ◽  
Richard Craig
Keyword(s):  
Experimental Period ◽  
Floral Organ ◽  
Leaf Primordia ◽  
Floral Meristem ◽  
Growth Chamber ◽  
Photon Flux ◽  
Floral Initiation ◽  
Photosynthetic Photon Flux ◽  
Floral Ontogeny

Floral ontogeny of two cultivars of Pelargonium ×domesticum L.H. Bailey, (regal pelargonium) `Duchess' and `Jennifer', was examined. Plants of both cultivars were grown together in a growth chamber at 15.5 °C with a photosynthetic photon flux of 10 mol·m-2·d-1. Meristems were examined at 5-day intervals over an experimental period of 170 days. The initial vegetative meristem was convex with leaf primordia initiated on either side in an alternate pattern. Early floral initiation was characterized by formation of two clefts on either side of the meristem. Between the clefts new meristems developed. Proliferation of meristems continued until numerous meristems were organized in a cluster arrangement at the apex of the shoot. New meristems lacked leaf primordia and would develop into flowers. Floral organ primordia on a floral meristem were initiated in a succession of four whorls: sepals, petals, androecia, and gynoecium.

scholarly journals Influence du mode d'utilisation de l'éclairage d'appoint sur la productivité et la physiologie de la tomate de serre

1991 ◽  
Vol 71 (3) ◽  
pp. 923-932 ◽  
Author(s):  
François Vézina ◽  
Marc J. Trudel ◽  
André Gosselin
Keyword(s):  
High Pressure ◽  
Lycopersicon Esculentum ◽  
Key Words ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Tomato Plants ◽  
Distribution Mode ◽  
Key Words Tomato ◽  
Supplemental Lighting ◽  
H 20

Tomato plants (Lycopersicon esculentum 'Vedettos') were submitted to 10 light treatments obtained by modifying the supplemental photosynthetic photon flux (FPP) (0, 100, 150 μmol m−2 s−1), the photoperiod (natural, 14 h, 17 h, 20 h, 24 h) and the light distribution mode (one or two dark periods). Supplemental light was supplied by high-pressure vapor sodium lamps (HPS). Our results showed that supplemental lighting at a level of 150 μmol m−2 s−1 (PAR) helped to maintain a weekly yield of over 1 kg m−2 during November, December and January. Prolongation of the photoperiod over 14 h did not increase the yield. Plants exposed to continuous lighting were damaged even if they had been previously exposed to long photoperiods (17 and 20 h). For photoperiods of 17 and 20 h, lighting during the night which generated two dark periods per day damaged the plants and reduced the yields. Key words: Tomato (Lycopersicon esculentum), greenhouse, supplemental lighting, continuous lighting, yield, physiological disorders

Sign in / Sign up

Export Citation Format

Share Document