scholarly journals Effect of Wind and Soil Moisture on the Growth of `Bluecrop' (Vaccinium corymbosum L.)

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 648c-648
Author(s):  
W. Alan Erb ◽  
Mark Pyeatt

This study was conducted in the greenhouse by running two experiments at different temperature regimes (22°C day and 13°C night and 33°C day and 22°C night). One-year-old tissue culture propagated plants were irrigated at three different soil moisture tension levels (5, 15, and 30 cnbars) and either exposed to moving or still air. The moving air treatment was created by two 51-cm-diameter fans running at either low (5.6 mph) or medium (8.2 mph) speed. Each experiment included, forty-eight plants arranged in a randomized complete block design. Each block consisted of a greenhouse bench containing two fans, a plastic dividing wall and two plant replications for each treatment. Canopy volume measurements were taken at the beginning, middle and end of each experiment to estimate growth rate. At the end of each experiment, total leaf area and leaf, stem and root dry weight data were collected. In the moderate temperature experiment, the still air treated plants had the highest canopy volume and leaf weight ratio while the moving air treated plants had the highest stem weight ratio. The only difference for the moisture treatments was the 5-cnbar treatment had the highest canopy volume. In the high temperature experiment, the still air treated plants had the highest canopy volume, total leaf area, leaf dry weight, shoot/root ratio, leaf weight ratio and leaf area duration while the moving air treated plants had the highest root weight ratio. The 5-cnbar treatment had the highest canopy volume and biomass accumulations. The 30-cnbar treatment had the highest root weight ratio.

HortScience ◽  
1994 ◽  
Vol 29 (11) ◽  
pp. 1298-1302 ◽  
Author(s):  
D. Bradley Rowe ◽  
Stuart L. Warren ◽  
Frank A. Blazich

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.


1998 ◽  
Vol 22 (4) ◽  
pp. 235-240 ◽  
Author(s):  
David B. South

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.


1970 ◽  
Vol 5 (1) ◽  
Author(s):  
Lia Karlina Br Sembiring ◽  
Rosita Sipayung ◽  
Irsal

Massive breeding is often the case with the availability of the amount of water that can be stored on the media. The aim of this research is to know the influence of media and the frequency of watering on the growth of robusta coffee seedlings and to find the best media and optimum watering frequency. This experiment was conducted at the Faculty of Agriculture, University of Sumatera Utara, Medan from June to September 2017. The experimental method used was Factorial Randomized Block Design with 2 treatment factors, ie 1: planting medium ie, topsoil ; topsoil: sand (2: 1); topsoil: rice husk (2: 1), topsoil: charcoal husk (2: 1) and factor 2: watering frequency ie, watered once a day; watered every 4 days; watered 7 days and watered once every 10 days. The variable was plant height, stem diameter, total leaf number, total leaf area, fresh crown weight, canopy dry weight, fresh root weight, root dry weight, longest root, and canopy and root ratio. The results showed that planting media treatment had a significant effect on plant height variables, stem diameter increase, leaf number, total leaf area, fresh crown weight, canopy dry weight, fresh root weight, root dry weight, and root canopy ratio. The best treatment of planting medium was found in topsoil treatment: rice husk (2: 1). The treatment of watering frequency had a significant effect on the stem diameter 2 - 12 of the week after planting move observation variable, total leaf area, fresh crown weight, dry crown weight, fresh root weight, and dry weight of roots. The best treatment frequency of watering hose is watering every 4 days. The interaction between the two treatments had a significant effect on the diameter of the stem diameter variable, the total leaf area and the fresh weight of the canopy.


Weed Science ◽  
2004 ◽  
Vol 52 (2) ◽  
pp. 271-280 ◽  
Author(s):  
Kevin D. Gibson ◽  
Albert J. Fischer ◽  
Theodore C. Foin

The development of optimal weed management strategies that rely, in part, on crop interference will require an understanding of how weeds compensate for limitations in above- and belowground resources. Trade-offs in the leaf morphology and biomass partitioning of rice and late watergrass were investigated under glasshouse conditions in 1999 and 2000. Both species responded to shade with increased height, reduced biomass, greater partitioning of biomass to leaves, and greater leaf area ratios. At the lowest light level (18% sunlight), plants of both species showed little response to nitrogen (N). However, height, tillers, biomass, and leaf area increased for plants grown at 50% and full sunlight as N increased from 0 to 224 kg N ha−1. Late watergrass exhibited more plasticity in specific leaf area and root weight ratio than rice in response to shade. This plasticity contributed to the ability of late watergrass to maintain a higher percent of its tillers and total dry weight than rice when sunlight was reduced by 50%. These results support the hypothesis that except at low light levels, limited N further reduces the growth of shaded late watergrass plants. Thus, weed management strategies that limit the plasticity of late watergrass by manipulating light and N availability are likely to be more effective than strategies that rely on manipulating a single resource.


1992 ◽  
Vol 117 (2) ◽  
pp. 216-219 ◽  
Author(s):  
Asiah A. Malek ◽  
Frank A. Blazich ◽  
Stuart L. Warren ◽  
James E. Shelton

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.


2002 ◽  
Vol 53 (12) ◽  
pp. 1375 ◽  
Author(s):  
O. R. Vignolio ◽  
C. Biel ◽  
F. de Herralde ◽  
J. P. L. Araújo-Alves ◽  
R. Savé

Soils with scarce plant covering are very susceptible to water and wind erosion. Two species recommended for permanent cover of soil are Lotus creticus creticus and Cynodon dactylon. The performance of both species cultivated in pure stands and in mixture and with 2 watering regimes, high (12.64 L/bag) and low (8.36�L/bag), was analysed in polyethylene bags between March and July in greenhouse conditions. With low watering the growth of both species was lower but mortality of plants was not observed. Growth of stems in L.�creticus and stolons in C. dactylon did not stop with low watering. The growth of C. dactylon was higher than that of L. creticus at both watering regimes. Total root and green shoot biomass of each species was affected by watering. Green leaf area, root weight ratio, root hydraulic resistance, and watering efficiency (g biomass/L watering) differed with the combination of species. Green leaf area, root hydraulic resistance, and watering efficiency were higher in C. dactylon than in L. creticus. Root weight ratio was higher in L. creticus than in C. dactylon, but the specific length and area of roots were higher in C. dactylon than in L. creticus. Net photosynthesis rate of each species was only affected by watering regime. Performance of both species was not affected by the mixture and it has the potential to be a successful ground cover.


1970 ◽  
Vol 36 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Sebahattin Albayrak ◽  
Necdet Çamas

Changes in plant growth viz. leaf area, leaf weight ratio, root weight ratio, dry leaf weight, dry root weight, total plant dry weight, specific leaf area, leaf thickness, leaf area ratio, net assimilation rate and relative growth rate due to the effects of environmental conditions such as temperature and light intensity were described by plant growth models. All equations produced for growth parameters were affected by light intensity and temperature. From multi-regression analysis, close relationships were found between actual and predicted growth parameters. The regression coefficients (r²) of the equations for growth parameters varied from 0.95 to 0.99 for cultivar Ecdogelb and 0.83 to 0.99 for cultivar Ecdorot, respectively.  


2019 ◽  
Vol 46 (No. 2) ◽  
pp. 98-106 ◽  
Author(s):  
Filippos Bantis ◽  
Kalliopi Radoglou

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.


1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.


Author(s):  
André Mantovani

Leaf succulence has important physiological and ecological implications. Currently it is quantified by Delf's index (fresh weight/leaf area) and fresh weight/ dry weight ratio. Both indeces are reconsidered and a new index is proposed. Shade and sun leaves from terrestrial, hemiepiphytic and epiphytic aroids were studied. Delf's formula, which does not consider dry weight, overestimated leaf succulence. As fresh weight / dry weight ratio (fw / dw) does not consider leaf area, plants with the same fw / dw ratio were more than five times different in area. The last case was only possible with a decrease in surface / volume ratio and a increase of mesophyll thickness, components not measured by fw / dw ratio. The new index proposed here, which takes into consideration dry weight and leaf area, showed a high correlation to mesophyll thickness.


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