Initial Growth of Seedlings of Mountain Laurel as Influenced by Day/Night Temperature

Seedlings of mountain laurel (Kalmia latifolia L.) were grown for 16 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, and dry weights of leaves, stems, and roots were influenced by day and night temperatures. The night optimum for all dry weight categories was 22C. Dry matter production was lowest with nights at 14C. Total plant dry weight and dry weights of tops, leaves, and stems were maximized with days at 26C, but for roots the optimum was 22C. Dry weight accumulation was lower with days at 18 or 30C. Responses of leaf area were similar to that of total plant dry weight, with optimum days and nights at 26 and 22C, respectively. Within the optimal day/night temperature range of 22-26/22C for dry weights, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) increased with day temperatures up to 30C and were highest with nights at 14 or 26C. Leaf weight ratio (leaf dry weight: total plant dry weight) decreased with increasing night temperature, and increased curvilinearly in response to day temperature with the minimum at 26C. Stem weight ratio (stem dry weight: total plant dry weight) increased with increasing day or night temperature. Root weight ratio (root dry weight: total plant dry weight) was highest with nights at 18 or 22C and decreased with days >22C. Net leaf photosynthetic rate was maximized with days at 26C.

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Initial Growth of Rosebay Rhododendron Seedlings as Influenced by Day and Night Temperatures

HortScience ◽

10.21273/hortsci.28.7.705 ◽

1993 ◽

Vol 28 (7) ◽

pp. 705-707 ◽

Cited By ~ 2

Author(s):

Mark C. Starrett ◽

Frank A. Blazich ◽

Stuart L. Warren

Keyword(s):

Dry Matter ◽

Weight Ratio ◽

Dry Weight ◽

Dry Matter Production ◽

Similar Response ◽

Initial Growth ◽

Night Temperature ◽

Root Dry Weight ◽

Matter Production ◽

Total Plant

Rosebay rhododendron (Rhododendron maximum L.) seedlings were grown in controlled-environment chambers for 14 weeks under long (9-hour) days at 18, 22, 26, or 30C in factorial combination with 15-hour nights at 14, 18, 22, or 26C. Total dry-matter production was lowest for 18C days and highest for 26C days. A similar response occurred for top, leaf, root, and stem dry weights. Nights at 22C maximized total plant, top, leaf, and stem dry weights. The optimum day/night cycle for dry-matter production was 26/22C. Leaf area was optimum with 18C nights. Leaf weight ratio (leaf dry weight: total plant dry weight) increased with an increase in night temperature to a maximum at 22C. Root weight ratio (root dry weight: total plant dry weight) decreased with an increase in night temperature to a minimum at 22C. Stem weight ratio (stem dry weight: total plant dry weight) and shoot: root ratio (top dry weight: root dry weight) were not influenced significantly by day or night temperature. A day/night cycle of 26/22C seems to be optimal for producing-salable plants.

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Initial Growth of Seedlings of Flame Azalea in Response to Day/Night Temperature

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.117.2.216 ◽

1992 ◽

Vol 117 (2) ◽

pp. 216-219 ◽

Cited By ~ 2

Author(s):

Asiah A. Malek ◽

Frank A. Blazich ◽

Stuart L. Warren ◽

James E. Shelton

Keyword(s):

Leaf Area ◽

Weight Ratio ◽

Dry Weight ◽

Night Temperature ◽

Total Leaf Area ◽

Root Dry Weight ◽

Total Leaf ◽

Total Plant ◽

Top Dry Weight ◽

Leaf Dry Weight

Seedlings of flame azalea [Rhododendron calendulaceum (Michx.) Torr] were grown for 12 weeks under long-day conditions with days at 18, 22, 26, or 30C for 9 hours in factorial combination with nights at 14, 18, 22, or 26C for 15 hours. Total plant dry weight, top dry weight, leaf area, and dry weights of leaves, stems, and roots were influenced by day and night temperatures and their interactions. Dry matter production was lowest with nights at 14C. Root, leaf, top, and total dry weights were maximized with days at 26C in combination with nights at 18 to 26C. Stem dry weight was maximized with days at 26 to 30C and nights at 22C. Leaf area was largest with days at 18 and 26C in combination with nights at 18 or 26C. Within the optimal, day/night temperature range of 26 C/18-26C for total plant dry weight, there was no evidence that alternating temperatures enhanced growth. Shoot: root ratios (top dry weight: root dry weight) were highest with days at 18 and 30C. Leaf area ratio (total leaf area: total plant dry weight) was highest and specific leaf area (total leaf area: leaf dry weight) was largest when days and nights were at 18C and were lower at higher temperatures. Regardless of day/night temperature, leaf weight ratio (leaf dry weight: total plant dry weight) was higher than either the stem weight ratio (stem dry weight: total plant dry weight) or root weight ratio (root dry weight: total plant dry weight). Net leaf photosynthetic rate increased with day temperatures up to 30C.

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Seedling Growth of Catawba Rhododendron. I. Temperature Optima, Leaf Area, and Dry Weight Distribution

HortScience ◽

10.21273/hortsci.29.11.1298 ◽

1994 ◽

Vol 29 (11) ◽

pp. 1298-1302 ◽

Cited By ~ 1

Author(s):

D. Bradley Rowe ◽

Stuart L. Warren ◽

Frank A. Blazich

Keyword(s):

Leaf Area ◽

Seedling Growth ◽

Weight Ratio ◽

Dry Weight ◽

High Elevation ◽

Root Weight ◽

Root Dry Weight ◽

Leaf Weight Ratio ◽

Leaf Weight ◽

Total Plant

Catawba rhododendron (Rhododendron catawbiense Michx.) seedlings of two provenances, Johnston County, N.C. (35°45′N, 78°12′W, elevation = 67 m), and Yancey County, N.C. (35°45′N, 82°16′W, elevation = 1954 m), were grown in controlled-environment chambers for 18 weeks with days at 18, 22, 26, or 30C in factorial combination with nights at 14, 18, 22, or 26C. Shoot and root dry weights and total leaf areas of seedlings of the Yancey County provenance (high elevation) exceeded (P ≤ 0.05) those of the Johnston County (low elevation) provenance at all temperature combinations. Leaf area was maximal at 22/22C, 18/26C, and 22/26C and minimal at 30/14C (day/night). Shoot dry weight responded similarly. Root dry weight decreased linearly with increasing day temperature, but showed a quadratic response to night temperature. Leaf weight ratio (leaf dry weight: total plant dry weight) increased, while root weight ratio (root dry weight: total plant dry weight) decreased with increasing day temperature. Leaf weight ratio was consistently higher than either stem or root weight ratios. Day/night cycles of 22 to 26/22C appear optimal for seedling growth.

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Nitrogen Nutrition of Containerized Ternstroemia gymnanthera

Journal of Environmental Horticulture ◽

10.24266/0738-2898-21.2.73 ◽

2003 ◽

Vol 21 (2) ◽

pp. 73-77

Author(s):

Peter J. Conden ◽

Stuart L. Warren ◽

Frank A. Blazich

Keyword(s):

Nitrogen Nutrition ◽

Weight Ratio ◽

Dry Weight ◽

Mineral Nutrient ◽

Nutrient Concentrations ◽

Root Weight ◽

Stem Cuttings ◽

Root Dry Weight ◽

Constant Rate ◽

Total Plant

Abstract Rooted stem cuttings of Japanese ternstroemia (Ternstroemia gymnanthera Thunb.) were grown in 3.8 liter (#1) plastic containers utilizing a substrate of pine bark: sand (8: 1 by vol) amended with micronutrients and dolomitic limestone. Plants were fertilized every other day with a solution consisting of P (K2H2PO4) at a constant rate of 30 mg/liter (ppm), K (K2SO4 and K2H2PO4) at a constant rate of 60 mg/liter (ppm), and a variable rate of N (NH4NO3) at 0, 10, 20, 40, 80, 160, or 320 mg/liter (ppm). Leaf area and shoot (stems and leaves) dry weight increased with increasing N application rate (NAR) until a plateau was reached at 117 mg/liter (ppm). Root: shoot ratio was 0.8 in non-fertilized plants, and decreased to ≈0.1 with N ≥ 104 mg/liter (ppm). Root dry weight and root area increased in response to increasing NARs, reaching a plateau with N at 86 and 70 mg/liter (ppm), respectively. Leaf weight ratio (leaf dry weight ÷ total plant dry weight) increased from 0.2 with N at 0 mg/liter (ppm) to a plateau of ≈0.6 with N ≥ 109 mg/liter (ppm). Stem weight ratio (stem dry weight ÷ total plant dry weight) was 0.4 with N at 0 mg/liter (ppm) then leveled off at ≈0.3 with N ≥ 52 mg/liter (ppm). Root weight ratio (root dry weight ÷ total plant dry weight) decreased steadily from 0.4 with N at 0 mg/liter (ppm) to ≈0.1 with N ≥ 117 mg/liter (ppm). Shoot N, P, K, and S concentrations increased with increasing NARs, reaching plateaus at 117, 23, 124, and 183 mg/liter (ppm), respectively, while Mg was unaffected by NAR. Calcium concentrations increased to 0.75% with a NAR of 40 mg/liter (ppm), and decreased to 0.6 % with N ≥ 107 mg/liter (ppm). Root mineral nutrient concentrations of N, P, K, and S increased with increasing NARs, reaching plateaus of 287, 53, 39, and 195 mg/liter (ppm) respectively, whereas Ca and Mg were not affected by NAR.

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Needle-Clipping Longleaf Pine and Top-Pruning Loblolly Pine in Bareroot Nurseries

Southern Journal of Applied Forestry ◽

10.1093/sjaf/22.4.235 ◽

1998 ◽

Vol 22 (4) ◽

pp. 235-240 ◽

Cited By ~ 2

Author(s):

David B. South

Keyword(s):

Loblolly Pine ◽

Seedling Survival ◽

Longleaf Pine ◽

Weight Ratio ◽

Dry Weight ◽

Root Weight ◽

Root Weight Ratio ◽

Root Dry Weight ◽

Percentage Points ◽

Average Survival

Abstract Studies have shown that clipping needles of longleaf pine before outplanting can increase average seedling survival by 13 percentage points. Under some situations, the increase in survival might be due to a reduction in transpiration. For loblolly pine, top-pruning in the nursery might increase average survival by 6 percentage points. Benefits of pruning appear greater when seedlings experience stress after planting and when nonpruned seedlings have low root weight ratios (root dry weight/total seedling dry weight). On some droughty sites, a seedling with a 0.3 root weight ratio might have an 80% chance of survival, while a seedling with a 0.2 root weight ratio might only have a 53% chance of survival. In most studies where heights were measured after 3 yr in the field, pruned seedlings were the same height as nonpruned seedlings (± 7 cm). South. J. Appl. For. 22(4):235-240.

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Increasing Cell Size and Reducing Medium Compression Enhance Lettuce Transplant Quality and Field Production

HortScience ◽

10.21273/hortsci.31.2.184 ◽

1996 ◽

Vol 31 (2) ◽

pp. 184-189 ◽

Cited By ~ 8

Author(s):

Silvana Nicola ◽

Daniel J. Cantliffe

Keyword(s):

Cell Size ◽

Sandy Soil ◽

Shoot Growth ◽

Weight Ratio ◽

Dry Weight ◽

Root Weight ◽

Growth Ratio ◽

Root Dry Weight ◽

Total Dry Weight ◽

Initial Root

`South Bay' lettuce (Lactuca sativa L.) seedlings were grown in a greenhouse during winter, spring, and fall to investigate the effect of cell size and medium compression on transplant quality and yield. Four Speedling planter flats (1.9-, 10.9-, 19.3-, 39.7-cm3 cells) and two medium compression levels [noncompressed and compressed (1.5 times in weight)] were tested. The two larger cell sizes and compression of the medium led to increased plant shoot growth. Conversely, root weight ratio [RWR = (final root dry weight ÷ final total dry weight + initial root dry weight ÷ initial total dry weight) ÷ 2] was highest with the smaller cells without medium compression. Lettuce transplants were field-grown on sand and muck soils. The larger cells delayed harvest by >2 weeks for plants grown on muck soil, but yield was unaffected. When grown on sandy soil, earliness was enhanced from plants grown in 19- and 40-cm3 cells, but head weights were not affected in the spring planting. In fall, heads were heavier for plants grown in 11-, 19-, or 40-cm3 cells compared with those from 2-cm3 cells. On sandy soil, harvest was delayed 13 days in spring and 16 days in fall for plants grown in the smallest cell size. Using the two smaller cell sizes saved medium and space in the greenhouse and increased the root growth ratio, but it led to reduced plant growth compared to using the bigger cells. Yield and earliness were more related to season and soil type than to transplant quality. On sandy soil, plants grown in 2- and 11-cm3 cells matured later, and yield was significantly decreased (8.6%) in fall by using plants from the 2-cm3 cells compared to the other sizes. From our results, compressing the medium in the cells was not justified because it is more costly and did not benefit yield in the field.

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Seedling Growth of Atlantic White-Cedar as Influenced by Photoperiod and Day/Night Temperature

Journal of Environmental Horticulture ◽

10.24266/0738-2898-17.3.107 ◽

1999 ◽

Vol 17 (3) ◽

pp. 107-113

Author(s):

Laura G. Jull ◽

Frank A. Blazich ◽

L. Eric Hinesley

Keyword(s):

Seedling Growth ◽

Dry Weight ◽

Night Temperature ◽

White Cedar ◽

Chamaecyparis Thyoides ◽

Atlantic White Cedar ◽

Root Dry Weight ◽

Shoot Dry Weight ◽

Root Shoot Ratio ◽

Total Plant

Abstract Seedlings of Atlantic white-cedar [Chamaecyparis thyoides (L.) B. S. P.] were grown in controlled-environment chambers for 12 weeks under short-or long-day conditions with 9-hr days at 18, 22, 26 or 30C (64, 72, 79 or 86F) in factorial combination with 15-hr nights at 14, 18, 22 or 26C (57, 64, 72 or 79F). Dry matter production was influenced by photoperiod and day/night temperature. For all day temperature × photoperiod interactions, except root:shoot ratio, growth was highest under long days. Day × night temperature interactions occurred for all growth measurements except root dry weight. Root dry weight was highest at 30/22C (86/72F); top (shoot) dry weight at 26/22C (79/72F). Nights of 14C (57F) resulted in the lowest top dry weight. Total plant dry weight was highest at nights of 22C (72F) for all day temperatures. At days of 30C (86F), total plant dry weight was highest with nights ≤ 22C (72F); however, data for 30/22C (86/72F) and 26/22C (79/72F) were similar. The highest root: shoot ratio occurred at nights of 14C (57F) with days ≤ 26C (79F). Mean relative growth rate was highest at nights of 22C (72F) with days of 26C (79F) or 30C (86F). Maximum stem caliper occurred at days of 22C (72F) with nights ≥ 18C (64F). Height and crown width were highest at 26/22C (79/72F). A day/night cycle of 30/22C (86/72F) with long days was optimal for seedling growth.

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Biomass Partitioning and Yield of Three Asparagus Hybrids

HortScience ◽

10.21273/hortsci.33.3.487f ◽

1998 ◽

Vol 33 (3) ◽

pp. 487f-488

Author(s):

W. Alan Erb ◽

Linda Parsons ◽

Mark Pyeatt

Keyword(s):

Weight Ratio ◽

Dry Weight ◽

Biomass Partitioning ◽

Cultivar Differences ◽

Root Weight ◽

Root Dry Weight ◽

Total Dry Weight ◽

Sowing Seed ◽

Almost All ◽

Leaf Dry Weight

This study was conducted to learn when an asparagus plant partitions its biomass into leaves, stems, buds, and rhizomes, and roots and to determine when after harvest the crown of the plant is rejuvenated to the point that harvest can begin again. The plants used in this study were generated by sowing seed on Jan. 1995, transplanting seedlings into 1.8-L containers (5 sand: 4 soil: 1 peat) in Mar. 1995 and on Mar. 1996, placing the crowns into 9.5-L containers. During Fall 1996, the number of shoots per plant were recorded and this data was used to group plants into six classes. The study was started on 8 Apr. 1997 by first removing six plants/cultivar (one from each class) and biomass partitioning each crown into buds and rhizomes, and roots. The remaining plants were harvested eight times and after the final harvest on 20 Apr. another set of plants (six/cultivar) were partitioned. Starting on 3 June, a set of plants were partitioned every 2 weeks until 21 Oct., when growth stopped in the fall. Atlas and UC157 F1 produced the most spears and had the highest yield and they also had the highest total dry weight, leaf dry weight, and stem dry weight. There were no cultivar differences in rhizome and root dry weight. However, `Jersey Giant' and `Atlas' had the highest rhizome and root weight ratio. The highest bud dry weights occurred on 20 May, 23 Sept., 26 Aug., and 21 Oct. and the highest rhizome and root dry weights were on 21 Oct., 12 Aug., 26 Aug., and 23 Sept. The bud dry weight recorded on 12 Aug. was equal to the bud dry weight recorded on 8 Apr. Also on 12 Aug., leaf dry weight and rhizome and root dry weight were higher than almost all the other dates. In addition, above-ground shoot counts and bud dry weights were higher on 26 Aug. than on 12 Aug. All this data indicates that in this study sometime after 12 Aug. and before 26 Aug., the asparagus crown was completely rejuvenated and ready for another cycle of harvesting.

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Testing the potential of LEDs to enhance growth and quality characteristics of Salvia fruticosa

Horticultural Science ◽

10.17221/206/2017-hortsci ◽

2019 ◽

Vol 46 (No. 2) ◽

pp. 98-106 ◽

Cited By ~ 1

Author(s):

Filippos Bantis ◽

Kalliopi Radoglou

Keyword(s):

Root Biomass ◽

Weight Ratio ◽

Dry Weight ◽

Total Phenolic ◽

Root Weight ◽

Light Emitting ◽

Shoot Dry Weight ◽

Radiation Spectra ◽

Salvia Fruticosa ◽

Developmental Characteristics

The effect of light-emitting diodes (LED) with broad radiation spectra on developmental, physiological, and phytochemical characteristics of Greek sage (Salvia fruticosa L.) seedlings was assessed. Fluorescent (FL – control) tubes and four LED lights [AP67 (moderate blue, red and far-red), L20AP67 (moderate blue, red and far-red, high green), AP673L (moderate blue, high red) and NS1 (high blue and green, low red, high red : far-red, 1% ultraviolet)] were used in a growth chamber. Seedlings grown under FL, L20AP67 and AP673L exhibited the best morphological and developmental characteristics. FL led to inferior root biomass formation compared to all LEDs. AP67 promoted greater root-to-shoot dry weight ratio and dry-to-fresh overground and root weight ratios, but induced the least morphological and developmental characteristics. NS1 performed well regarding the root biomass production. Total phenolic content and the root growth capacity were not significantly affected. The present study demonstrates that L20AP67 and AP673L LEDs performed equally to FL light regarding the developmental characteristics. AP67 and NS1 may have the potential to be used for compact seedling production.

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