The effect of barley yellow dwarf virus on early plant growth in ryegrass (Lolium spp.)

1989 ◽  
Vol 40 (2) ◽  
pp. 293 ◽  
Author(s):  
DR Eagling ◽  
RJ Sward ◽  
GM Halloran

Measurements were made on the effect of barley yellow dwarf virus (BYDV) infection on the early growth of four commercial cultivars of ryegrass (Lolium spp.) under two different temperatures (24�C and 16�C). At 24'C, BYDV infection was associated with reduced root dry weight (30-40%) in all cultivars; the effect of infection on shoot dry weight and leaf area was variable. At 16�C, the effect of BYDV infection was variable, being associated with increases in root dry weight, shoot dry weight, and leaf area in one cultivar (Grasslands Ariki) and decreases in another (Victorian). In two other cultivars, root dry weight, shoot dry weight and leaf area were not significantly affected (P>0.05) by infection with BYDV.At 24�C, the reductions in root dry weight associated with BYDV infection were not concomitant with reductions in the root relative growth rates. Up to at least 28 days after inoculation (46-50 days after germination) reductions in root dry weight were associated with both aphid-feeding damage and virus infection. Experiments with the cultivar Victorian, showed that shoot dry weight was not significantly affected (P>0.05) by feeding with viruliferous (BYDV) or non-viruliferous aphids (Rhopalosiphum padi L.). At 16�C, changes in root and shoot dry weight were associated with changes in the root and shoot relative growth rates.

1958 ◽  
Vol 51 (3) ◽  
pp. 347-352 ◽  
Author(s):  
R. H. M. Langer

1. Swards of S. 48 timothy and S. 215 meadow fescue growing alone or together were sampled at intervals of 3 weeks throughout the season. The number and weight of leaves, stems and ears were determined, and leaf area was estimated.2. Despite high rainfall, the total number of tillers in both species declined from the beginning of the experiment until early July, but increased again from then onwards until the original complement had been approximately restored. The number of leaves failed to show a corresponding increase in the autumn because each tiller carried fewer leaves than earlier in the year.3. In the spring total dry weight increased more rapidly in meadow fescue than in timothy which in turn out-yielded meadow fescue later in the season. Both species attained their greatest dry weight soon after ear emergence, a period which was marked by considerable crop growth and relative growth rates.4. Leaf area index reached a maximum before total dry weight had increased to its highest level, but then declined in both species. Meadow fescue differed from timothy by producing a second crop of foliage after the summer with a leaf area index of about 7. This second rise appeared to be due mainly to increased leaf size in contrast to timothy whose leaves became progressively smaller towards the end of the season.5. The differences in growth between the species discussed with reference to their dates of ear emergence which in this experiment differed by about 6 weeks.


1963 ◽  
Vol 14 (6) ◽  
pp. 737
Author(s):  
LL Stubbs ◽  
WI Walbran

A comparison was made of the nitrate levels of healthy Algerian oats and those infected with barley yellow dwarf virus (BYDV), the plants being grown on three soil types in containers in an insect-screened glass-house, under conditions of low nitrogen nutrition. The nitrate level of virus-infected plants was significantly higher than that of healthy plants, and within the range considered to be toxic to ruminants. In plants grown in a peat-sand mix with abundant applied nitrogen, infected oats were not markedly dwarfed; their foliage dry weight was not significantly less than that of healthy oats, but nitrate accumulation was significantly less. The possible significance of the association between nitrate accumulation and BYDV infection in oats is discussed in relation to nitrate poisoning of livestock.


2007 ◽  
Vol 17 (4) ◽  
pp. 486-490 ◽  
Author(s):  
Sudeep Vyapari ◽  
S.M. Scheiber ◽  
E.L. Thralls

Three root ball conditions—nonroot-bound (NRB), root-bound (RB), and root-bound sliced (RBS)—were evaluated for their effect on plant growth of plumbago (Plumbago auriculata) during establishment and postestablishment in the landscape. At transplant, NRB plants were smaller than other treatments. Canopy size, shoot dry weight, root dry weight, and total biomass growth rates were faster for NRB plants compared with RB or RBS. By 6 and 8 weeks after transplanting, respectively, biomass and canopy size were similar among treatments. Rootbound and RBS plants were similar indicating root ball slicing does not affect growth in the landscape.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.


1984 ◽  
Vol 14 (6) ◽  
pp. 850-854 ◽  
Author(s):  
S. B. Rood ◽  
G. Daicos ◽  
T. J. Blake

Weekly applications of 0.4 mg gibberellic acid (GA) in 8 μL 95% ethanol micropipetted onto shoots of rooted cuttings increased Populuseuramericana (Dode) Guinier height growth by 54% and shoot dry weight by 25% after 21 days. Total leaf area increased by 21% as a result of more rapid leaf production and slightly larger leaf sizes. Root growth was unaffected by GA treatment. The observed GA-induced acceleration resulted from an increase in relative growth rate while mean net assimilation rate was unaffected. Owing to a substantial increase in the number and size of leaves, the leaf area ratio, representing the ratio of photosynthesizing to respiring material, increased. While direct micropipette application of GA promoted height growth and primary shoot dry weight accumulation, GA application through either foliar spray or soil drench also promoted the growth of secondary shoots. Application of GA to shoots was more effective in promoting shoot growth than application through the roots. Direct GA application also promoted the growth of P. alba L. × P. grandidentata Michx. and P. × canescens (Ait.) Smith × P. alba × P. grandidentata. Thus, GA can be used for hastening early growth of these trees under winter greenhouse conditions.


1990 ◽  
Vol 70 (4) ◽  
pp. 1199-1205 ◽  
Author(s):  
JEAN MASSON ◽  
ANDRÉ GOSSELIN ◽  
NICOLAS TREMBLAY

Tomato (Lycopersicon esculentum Mill. ’Springset’) and lettuce (Lactuca sativa L. ’Ithaca’) transplants were grown under natural and supplemental light (100 μmol m−2 s−1 PAR) and fertilized with four nitrogen doses (100, 200, 300, and 400 mg L−1 N). Supplemental light increased tomato shoot dry weight, shoot percent dry matter, leaf area, root dry weight, and root-to-shoot ratio. Lettuce transplants showed increased shoot and root dry weight as well as leaf area when supplemental light was present. For both species, nitrogen increased shoot dry weight and leaf area, but decreased shoot percent dry matter and root-to-shoot ratio. High nitrogen doses increased tomato and lettuce shoot dry weight and leaf area chiefly under supplemental light.Key words: Lycopersicon esculentum, Lactuca sativa, pretransplanting nutritional conditioning, seedling


1969 ◽  
Vol 49 (4) ◽  
pp. 465-470
Author(s):  
D. B. Wilson ◽  
A. Johnston

Seedlings of a native grass, rough fescue, Festuca scabrella Torr., and of a tame grass, tall fescue, Festuca arundinacea Schreb., were grown in the greenhouse for 10 weeks. Each week 20 plants of each species were destructively harvested for growth analysis. Leaf and tiller numbers and leaf lengths were recorded for an additional 10 plants of each species. Mean net assimilation rates of rough fescue were similar to those of tall fescue, but leaf area ratios were significantly lower. Thus, mean relative growth rates of rough fescue were less than those of tall fescue. Tiller numbers were similar for both species but rough fescue produced fewer leaves. Dry weight of tops of the tame grass produced during the 10-week period was about 17 times that produced by the native grass.


1966 ◽  
Vol 46 (6) ◽  
pp. 611-617 ◽  
Author(s):  
R. Kaul

Seedlings of wheat, oats, and barley were grown in nutrient solution and subjected to uniform water stresses by the addition of different amounts of polyethylene glycol to the medium. The polyethylene glycol was refined by passage through a combined millipore – ion exchange filter. The solution was circulated by an automatic system which drained and refilled growth tanks once every 45 minutes. Relative growth rates, calculated from changes in dry weight, were used as a measure of drought tolerance. Between the second and the sixth leaf stages, but not at the first leaf stage, the drought tolerance of Thatcher wheat was significantly greater than that of Exeter oats or Husky barley. Oats and barley responded similarly to water stress.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1041B-1041
Author(s):  
Jason J. Griffin ◽  
William R. Reid ◽  
Dale Bremer

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.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 619d-619
Author(s):  
Muntubani D. S. Nzima ◽  
George C. Martin ◽  
Chic Nishijima

Trees that fruited during 1990 retained 67.3% of the inflorescence buds produced per branch in 1991 compared to 63.1% for trees that were defoliated immediately after harvest in 1990 and 21.3% by trees that were fruiting in 1991. Shading reduced bud retention similar to fruiting. Defoliation after nut harvest accentuated the delayed costs of reproduction caused by previous season's fruiting whereas shading produced significantly greater immediate costs. Shading effects on the allocation of carbon to buds, leaves and shoots were similar to those of fruiting. Leaf net photosynthesis under shade conditions was reduced to 14.27% of control trees and this led to a significant reduction in the relative growth rates of all the organs surveyed.


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