scholarly journals Postproduction Leaching Affects the Growing Medium and Respiration of Subirrigated Poinsettias

HortScience ◽  
2000 ◽  
Vol 35 (2) ◽  
pp. 250-253 ◽  
Author(s):  
Marc van Iersel
Keyword(s):  
Dark Respiration ◽  
Plant Stress ◽  
Middle Layer ◽  
Bottom Layer ◽  
Euphorbia Pulcherrima ◽  
Whole Plant ◽  
Growing Medium ◽  
Plant Photosynthesis ◽  
Saturated Medium ◽  
Fertilizer Solution

Poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch) were grown in pots filled with 1.5 L of soilless growing medium and subirrigated daily with a fertilizer solution containing N at 210 mg·L-1 [electrical conductivity (EC) = 1.5 dS·m-1] for 128 days. After production, plants were placed in a whole-plant photosynthesis system and the effects of applying different volumes of water (0, 0.75, 1.5, and 3 L) to the top of the pots were quantified. Leaching with 0.75, 1.5, or 3 L of water reduced the EC in the top and middle layers of the growing medium. Applications of 0.75 or 1.5 L of water significantly increased the EC in the bottom third of the pots, where most of the root growth occurred. However, even in these treatments the EC in the bottom layer was only 2.6 dS·m-1 (saturated medium extraction method), which is well within the recommended range. The 0.75- and 1.5-L treatments also reduced the respiration rate of the plants by 20%, but none of the treatments had a significant effect on the photosynthesis of the plants. Regression analysis indicated a negative correlation between the EC of the bottom layer of the growing medium and dark respiration, while the EC of the top and middle layer had no significant effect on respiration. Although top watering can increase the EC in the bottom layer of the growing medium, this effect is unlikely to be large enough to cause significant plant stress and damage.

scholarly journals 155 Fertilizer Concentration Affects Whole Plant CO2 Exchange and Growth of Subirrigated Pansies

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 416D-416
Author(s):  
Marc van Iersel ◽  
Jong-Goo Kang
Keyword(s):  
Root System ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Bedding Plants ◽  
Whole Plant ◽  
Growing Medium ◽  
Wide Range ◽  
K Deficiency ◽  
Plant Photosynthesis

Subirrigation is an economically attractive irrigation method for producing bedding plants. Because excess fertilizer salts are not leached from the growing medium, salts can accumulate in the growing medium. Fertilizer guidelines developed for overhead irrigation may not be appropriate for subirrigation systems. Our objective was to quantify the effect of the fertilizer concentration (N at 0, 135, 285, and 440 mg·L–1) on whole-plant CO2 exchange and growth of subirrigated pansies. Whole plant CO2 exchange rate (net photosynthesis and dark respiration) was measured once every 10 min for 31 days. Whole-plant photosynthesis, dark respiration, and carbon use efficiency increased during the experiment. Fertilizer concentration started to affect the growth rate of the plants after approximately 7 days. Maximum photosynthesis and growth were achieved with N at about 280 mg·L–1 in the fertilizer solution [electrical conductivity = 2 dS·m–1]. Growth was reduced by ≈10% when the plants were fertilized with N at 135 and 440 mg·L–1 compared to 280 mg·L–1. Growth of plants watered without any fertilizer was greatly reduced, and plants showed symptoms of N and K deficiency. The size of the root system decreased and the shoot: root ratio increased with increasing fertilizer concentration, but the size of the root system was adequate in all treatments. These results indicate that subirrigated pansies can tolerate a wide range of fertilizer concentrations with relatively little effect on plant growth.

scholarly journals Optimum Potassium Concentrations in Recirculating Subirrigation for Selected Greenhouse Crops

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
Trisha Blessington Haley ◽  
David Wm. Reed
Keyword(s):  
Growth Parameters ◽  
New Guinea ◽  
Middle Layer ◽  
Maximum Growth ◽  
Bottom Layer ◽  
Growing Medium ◽  
K Fertilizer ◽  
K Concentration ◽  
New Guinea Impatiens ◽  
Recommended Level

Two experiments were conducted to investigate the effect of K fertilizer rates on growth of New Guinea impatiens (Impatiens Hawkeri Bull.), vinca (Catharanthus roseus (L.) G. Don) and petunia (Petunia ×hybrida Hort. Vilm.-Andr.) in a recirculating subirrigation system. Based on a variety of growth parameters, a broad range of K concentrations allowed maximum growth, notably 1 to 6 mM for New Guinea impatiens `Ovation Salmon Pink Swirl', 2 mm for New Guinea impatiens `Cameo' and `Illusion', 2 to 8 mm for vinca `Pacifica Apricot', and 2 to 16 mm for petunia `Trailing Wave Misty Lilac'. Thus, the lowest concentration that allowed maximum growth was 1 to 2 mm K. A third experiment compared the optimum K concentration and K balance of vinca grown with recirculating subirrigation versus top-watering. Based on a variety of growth parameters of vinca `Pacifica Red', the lowest concentration that allowed maximum growth was 2 mm K with recirculating subirrigation and 4 mm K with top-watering. The K balance demonstrated that subirrigated plants were twice as efficient in K use compared to the top-watered plants. Leachate loss was the major contributor to inefficiency in top-watered plants. Electrical conductivity (EC) of the growing medium remained below the recommended level of 1.2 dS·m-1 in both irrigation methods at K concentrations of 16 mm and below in the bottom layer and 8 mm and below in the middle layer. In the top layer of the growing medium, EC was above the recommended level at all K concentrations tested in subirrigation at all concentrations, and in top-watering at 16 mm and above.

scholarly journals Nutrient Solution Concentration Affects Whole-plant CO2 Exchange and Growth of Subirrigated Pansy

2002 ◽  
Vol 127 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Marc W. van Iersel ◽  
Jong-Goo Kang
Keyword(s):  
Plant Growth ◽  
Exchange Rates ◽  
Leaf Area ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Gross Photosynthesis ◽  
Whole Plant ◽  
Wide Range ◽  
Shoot To Root Ratio ◽  
Fertilizer Solution

To determine the effect of fertilizer concentration on plant growth and physiology, whole-plant C exchange rates of pansies (Viola ×wittrockiana Gams.) subirrigated with one of four fertilizer concentrations were measured over 30 days. Plants were watered with fertilizer solutions with an electrical conductivity (EC) of 0.15, 1.0, 2.0, or 3.0 dS·m-1 (N at 0, 135, 290, or 440 mg·L-1, respectively). Plants watered with a fertilizer solution with an EC of 2 dS·m-1 had the highest shoot dry weight (DW), shoot to root ratio, leaf area, leaf area ratio (LAR), and cumulative C gain at the end of the experiment compared to those watered with a solution with a higher or lower EC. Shoot tissue concentrations of N, P, K, S, Ca, Fe, Na, and Zn increased linearly with increasing fertilizer concentration. A close correlation between final DW of the plants and the measured cumulative C gain (CCG) (r2 = 0.98) indicated that the C exchange rates were good indicators of plant growth. There were quadratic relationships between fertilizer EC and gross photosynthesis, net photosynthesis, and dark respiration, starting at 13, 12, and 6 days after transplanting, respectively. Although plants fertilized with a fertilizer solution with an EC of 2 dS·m-1 had the highest C exchange rates, the final differences in shoot DW and CCG among ECs of 1.0, 2.0, and 3.0 dS·m-1 were small and it appears that pansies can be grown successfully with a wide range of fertilizer concentrations. Plants with a high LAR also had higher DW, suggesting that increased growth was caused largely by increased light interception. A detrimental effect of high fertilizer concentrations was that it resulted in a decrease in root DW and a large increase in shoot to root ratio.

scholarly journals Whole-plant Photosynthesis of Containerized Hydrangeas and Abelias as Affected by Substrate Moisture Content

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1111D-1111 ◽  
Author(s):  
Marc W. van Iersel ◽  
Sue Dove
Keyword(s):  
Growth Rate ◽  
Drought Stress ◽  
Moisture Content ◽  
Water Potential ◽  
Photosynthetic Rate ◽  
Severe Drought ◽  
Whole Plant ◽  
Growing Medium ◽  
Plant Photosynthesis ◽  
Substrate Moisture

Efficient water use in nurseries is increasingly important. In recent years, new soil moisture sensors (ECH2O probes) have become available, making it possible to monitor the moisture content of the growing medium in containers. One piece of information that is lacking for fully-automated irrigation systems is how much water actually needs to be present in the growing medium to prevent detrimental effects of drought on plants. We determined the effect of substrate moisture on photosynthesis and plant water relations of hydrangea and abelia. Growth rates of these species were measured during two subsequent drying cycles to determine how drought affects the growth rate of these species. Whole-plant photosynthesis, an indicator of growth rate, of both species remained stable as the volumetric moisture content of the substrate dropped from 25% to 15%, with pronounced decreases in photosynthesis at lower substrate moisture levels. Abelias and hydrangeas wilted when the substrate moisture level dropped to 6.3% and 8.3%, respectively. At wilting, abelias had lower leaf water potential (–3.7 MPa) than hydrangeas (–1.8 MPa). After the plants were watered at the end of the first drying cycle, the photosynthesis of the plants did not recover to pre-stress rates, indicating that the drought stress caused a long-term reduction in photosynthesis. Despite the more severe drought stress in the abelias (both a lower substrate water content and lower water potential at wilting), abelias recovered better from drought than hydrangeas. After the plants were watered at the end of the first drying cycle, the photosynthetic rate of abelias recovered to ≈70%, while the photosynthetic rate of the hydrangeas recovered to only 62% of the pre-stress rate.

scholarly journals Light Intensity and Fertilizer Concentration: II. Optimal Fertilizer Solution Concentration for Species Differing in Light Requirement and Growth Rate

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1293-1297 ◽  
Author(s):  
Krishna S. Nemali ◽  
Marc W. van Iersel
Keyword(s):  
Bottom Layer ◽  
Solution Concentration ◽  
Dry Mass ◽  
Photon Flux ◽  
Average Height ◽  
Photosynthetic Photon Flux ◽  
Starter Fertilizer ◽  
Upper Limits ◽  
Growing Medium ◽  
Fertilizer Solution

To evaluate the effects of increasing photosynthetic photon flux (PPF) on optimal fertilizer concentrations, we grew wax begonia (Begonia semperflorens-cultorum Hort.) and petunia (Petunia ×hybrida Hort. Vilm-Andr.) seedlings in a soilless growing medium without starter fertilizer under three PPF treatments (high, medium, and low corresponding to an average daily PPF of 23.2, 15.6, and 9.8 mol·m-2.d-1, respectively) and subirrigated with six fertilizer concentrations [electrical conductivity (EC) of 0.12, 0.65, 1.18, 1.71, 2.24, and 2.77 dS·m-1]. Compared to low PPF, shoot dry mass of wax begonia and petunia seedlings increased 2- and 3-fold, respectively, at high PPF. Fertilizer EC resulting in maximum shoot dry mass was the same (1.28 and 1.87 dS·m-1 for wax begonia and petunia, respectively) in the three PPF treatments. Shoot dry mass and leaf area of petunias decreased little at higher than optimal fertilizer EC in the three PPF treatments, while growth of begonia was inhibited at high fertilizer EC. The optimal fertilizer range, calculated as the lower and upper limits of fertilizer EC within which plant growth was not reduced by >10% as compared to the optimum EC was 0.65 to 1.71 dS·m-1 in wax begonia and 1.18 to >2.77 dS·m-1 for petunia. Compared to those grown at 1.18 dS·m-1, wax begonias grown at 1.71 dS·m-1 had similar dry mass, but were shorter in all three PPF treatments (average height reduction of 6.5%). In general, EC of the top layer of the growing medium was higher than that of the bottom layer of the growing medium, and this difference increased with increasing EC.

scholarly journals Medium-incorporated PEG-8000 Reduces Elongation, Growth, and Whole-canopy Carbon Dioxide Exchange of Marigold

HortScience ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Stephanie E. Burnett ◽  
Marc W. van Iersel ◽  
Paul A. Thomas
Keyword(s):  
Carbon Dioxide ◽  
Polyethylene Glycol ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Carbon Dioxide Exchange ◽  
Seedling Height ◽  
Tagetes Patula ◽  
Whole Plant ◽  
Growing Medium ◽  
Peg 8000

French marigold (Tagetes patula L. `Boy Orange') was grown in a peat-based growing medium containing different rates (0, 15, 20, 30, 42, or 50 g·L–1) of polyethylene glycol 8000 (PEG-8000) to determine if PEG-8000 would reduce seedling height. Only 28% to 55% of seedlings treated with 62, 72, or 83 g·L–1 of PEG-8000 survived, and these treatments would be commercially unacceptable. Marigolds treated with the remaining concentrations of PEG-8000 had shorter hypocotyls, and were up to 38% shorter than nontreated controls at harvest. Marigold cotyledon water (ψw), osmotic (ψs), and turgor (ψp) potentials were significantly reduced by PEG-8000, and ψp was close to zero for all PEG-treated seedlings 18 days after seeding. Whole-plant net photosynthesis, whole-plant dark respiration, and net photosynthesis/leaf area ratios were reduced by PEG-8000, while specific respiration of seedlings treated with PEG-8000 increased. Marigolds treated with concentrations greater than 30 g·L–1 of PEG-8000 had net photosynthesis rates that were close to zero. Fourteen days after transplanting, PEG-treated marigolds were still shorter than nontreated seedlings and they flowered up to 5 days later. Concentrations of PEG from 15 to 30 g·L–1 reduced elongation of marigold seedlings without negatively affecting germination, survival, or plant quality. It appears that marigold seedlings were shorter because of reduced leaf ψp and reductions in net photosynthesis.

scholarly journals A COMPARISON OF LEAF AND WHOLE PLANT NET PHOTOSYNTHESIS IN ALSTROEMERIA

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 576c-576
Author(s):  
E.D. Leonardos ◽  
M.J. Tsujita ◽  
B. Grodzinski ◽  
T.J. Blom
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Gas Analysis ◽  
Whole Plant ◽  
Plant Photosynthesis ◽  
Mutual Shading ◽  
Photosynthetic Responses ◽  
Analysis System ◽  
Two Stages

Gas exchange (net photosynthesis Pn, dark respiration, transpiration, and stomatal resistance) of `Jaqueline' Alstroemeria, grown in pots in a greenhouse, were measured. Measurements were made under laboratory conditions using an open-flow infrared gas analysis system for leaf studies, and a semi-closed computer controlled whole plant photosynthesis system for whole plant studies. Apical fully expanded leaves on non-flowering and flowering (at two stages) shoots had similar photosynthetic responses in respect to photosynthetically active radiation (PAR) and to CO2 concentration. Light saturation occurred at 600 umol/m2/s PAR with maximum leaf Pn rates ranging from 9 to 11 umol CO2/m2/s. CO2 saturation was estimated at approximately 1100 to 1200 ppm with maximum leaf Pn rates from 17 to 22 umol CO2/m2/s. Whole plant Pn rates increased with increased PAR. Maximum rates 4 to 5 umol CO2/m2/s (half that of individual leaves) occurred at approximately 1000 to 1100 umol/m2/s PAR. CO2 saturation was estimated at 1100 to 1200 ppm, with maximum whole plant Pn rates ranging from 7 to 8 umol CO2/m2/s. These data will be discussed in relation to respiration and mutual shading at the leaf canopy.

Effect of irradiance on growth and photosynthesis of Populus × euramericana clones

1978 ◽  
Vol 8 (1) ◽  
pp. 94-99 ◽  
Author(s):  
F. E. Fasehun
Keyword(s):  
Growth Rate ◽  
Laboratory Experiments ◽  
Dark Respiration ◽  
High Irradiance ◽  
Dark Respiration Rate ◽  
Photosynthetic Rates ◽  
Populus Euramericana ◽  
Unit Leaf ◽  
Whole Plant ◽  
Plant Photosynthesis

Greenhouse and laboratory experiments were conducted to determine the effect of irradiance level on growth and photosynthesis of three Populus × euramericana clones selected to exhibit differences in growth rate when grown under full sunlight. Individual plants were started from apical cuttings and grown in the greenhouse for 13 weeks under three levels of shading (37%, 75%, and 100% full light). Rates of leaf and whole plant photosynthesis and dark respiration were measured with an infrared gas analyzer.Clone 5323 grew relatively well under all irradiance levels, and the older leaves of this clone had the highest photosynthetic rates per unit leaf area under the higher growth irradiances. Clone 5326, which had the least growth, also had the lowest per-plant photosynthesis rate under all irradiance levels. Clone 5321 had per-plant photosynthetic rates comparable with those of clone 5323 but a higher dark respiration rate when grown at the high irradiance levels.

scholarly journals Responses of Angelica acutiloba Kitagawa Transplants to Elevated Ambient CO2 Concentration

HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 851-855
Author(s):  
Ming Li ◽  
Wei-tang Song
Keyword(s):  
Dark Respiration ◽  
Growth Management ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Relative Growth ◽  
Whole Plant ◽  
Plant Photosynthesis ◽  
Angelica Acutiloba ◽  
Ambient Co2

Long-term exposure to an elevated ambient carbon dioxide (eCO2) concentration could weaken or diminish the enhancement of plant photosynthesis and growth. To monitor this response and offer references for growth management, the whole-plant photosynthetic rate (Pn,w) and dark respiration rate (Rd,w) of Angelica acutiloba Kitagawa transplants were monitored with a growth chamber. The results showed that eCO2 increased both the Pn,w and Rd,w by (79 ± 42) % and (126 ± 51) %. The dry weight of transplants under eCO2 was 33.6% greater than that under aCO2. However, the photosynthetic acclimation to eCO2 occurred. The increase in the Pn,w was maintained until the end of the experiment due to increased leaf area. Moreover, the increase in plant dry weight mainly occurred in the first 15 days of treatment. Furthermore, the dry weight estimated based on the Pn,w and Rd,w agreed well with the measured dry weight. The relative growth rate (RGR) calculated with the estimated dry weight demonstrated the response of transplant growth to eCO2. These results indicated that the proposed method can be used to monitor the response of plant growth to eCO2.

scholarly journals High-Gain Vivaldi Antenna with Wide Bandwidth Characteristics for 5G Mobile and Ku-Band Radar Applications

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 667
Author(s):  
Raza Ullah ◽  
Sadiq Ullah ◽  
Farooq Faisal ◽  
Rizwan Ullah ◽  
Dong-you Choi ◽  
...  
Keyword(s):  
Mobile Communication ◽  
Middle Layer ◽  
Bottom Layer ◽  
High Gain ◽  
Mirror Image ◽  
Radar Applications ◽  
Vivaldi Antenna ◽  
5G Mobile Communication ◽  
Element Array ◽  
Ku Band

In this paper, antipodal Vivaldi antenna is designed for 5th generation (5G) mobile communication and Ku-band applications. The proposed designed has three layers. The upper layer consists of eight-element array of split-shaped leaf structures, which is fed by a 1-to-8 power divider network. Middle layer is a substrate made of Rogers 5880. The bottom layer consists of truncated ground and shorter mirror-image split leaf structures. The overall size of the designed antenna is confined significantly to 33.31 × 54.96 × 0.787 (volume in mm3), which is equivalent to 2λo× 3.3λo× 0.05λo (λo is free-space wavelength at 18 GHz). Proposed eight elements antenna is multi-band in nature covering Ku-bands (14.44–20.98 GHz), two millimeter wave (mmW) bands i.e., 24.34–29 GHz and 33–40 GHz, which are candidate frequency bands for 5G communications. The Ku-Band is suitable for radar applications. Proposed eight elements antenna is very efficient and has stable gain for 5G mobile communication and Ku-band applications. The simulation results are experimentally validated by testing the fabricated prototypes of the proposed design.

Sign in / Sign up

Export Citation Format

Share Document