scholarly journals Effect of the Growth Regulator Uniconazole on Biomass Allocation of Bareroot Loblolly Pine Seedlings

2004 ◽  
Vol 28 (1) ◽  
pp. 41-47
Author(s):  
Andrew D. Barnes ◽  
David B. South

Abstract Improving seedling performance by reducing seedling height can be an important aspect of nursery management. The plant growth regulator uniconazole was applied to regulate height growth of nursery-grown loblolly pine (Pinus taeda L.) seedlings. Tests involving a foliar spray (0,0.125, 0.25, 0.5 and 1.0 kg ai/ha) or a wick application (0, 125, 250, 500, and 1000 ppm) were conducted in Alabama, Georgia, and South Carolina. The wick applicator consisted of a perforated plastic pipe covered with a sponge cylinder supplied by a reservoir. With both application methods, as the rate of uniconazole increased, seedling height, root-collar diameter, and biomass decreased. Compared to the controls, uniconazole decreased the percentage of seedlings with root-collar diameters greater than 4.7 mm. At lifting there was no difference among rates for root/shoot ratio, but root/shoot ratios of uniconazole treated seedlings increased significantly after outplanting. Eighteen months after outplanting, there were no treatment effects on seedling height or survival. Wick applications of uniconazole merit further research because of soil persistence and costs associated with spray applications. South. J. Appl. For. 28(1):41–47.

1982 ◽  
Vol 6 (1) ◽  
pp. 30-33 ◽  
Author(s):  
John L. Ruehle

Abstract Container-grown loblolly pine seedlings (Pinus taeda L.) with Pisolithus tinctorius, Thelephora terrestris, or no ectomycorrhizae (control) were outplanted on a South Carolina reforestation site. Two years after planting, seedlings initially colonized with Pisolithus or Thelephora had greater survival, height, and root collar diameter than control seedlings. Growth data were integrated into seedling volume indices (D²H). Seedlings with ectomycorrhizae at planting had nearly a three-fold greater D²H than seedlings initially without ectomycorrhizae. These results provided additional field validation for the hypothesis regarding benefits of ectomycorrhizae on this type of planting stock.


1990 ◽  
Vol 14 (4) ◽  
pp. 196-199 ◽  
Author(s):  
David B. South ◽  
Nancy J. Stumpff

Abstract Stripping short roots from individual loblolly pine (Pinus taeda L.) seedlings was accomplished by pulling the root system through a closed fist either 1, 2, or 4 times. The root growth potential (RGP) of the seedlings was directly related to the intensity of stripping. One stripping removed approximately 2% of the total root weight, yet reduced the number of root apices by 22% and caused a 47% reduction in RGP. Four strippings removed approximately 11% of the root weight, reduced the root/shoot ratio by about 9% and resulted in a 69% reduction in RGP. Although stripping of roots reduced both shoot and root growth, the relative effect on new shoot growth was not as great as with new root growth. Root stripping effectively eliminated any correlation between seedling diameter and RGP. South. J. Appl. For. 14(4):196-199.


1993 ◽  
Vol 17 (2) ◽  
pp. 80-83 ◽  
Author(s):  
J. P. Barnett ◽  
J. M. McGilvray

Abstract The performance of container and bareroot loblolly pine (Pinus taeda L.) seedlings from the same improved seedlot was compared on highly productive bottomland sites in South Carolina. At the time of planting, size and quality of the open-grown container stock were equal to or betterthan bareroot material. When outplanting conditions were ideal, field plantings in March, April, and May of 2 successive years indicated equal performance of the 2 stock types. When conditions were more stressful, container stock survived and grew better than bareroot seedlings. Needle-tipburn caused by postplanting applications of herbicides had no long-term effects on seedling growth. South. J. Appl. For. 17(2):80-83.


1987 ◽  
Vol 11 (3) ◽  
pp. 139-143 ◽  
Author(s):  
C. L. Tuttle ◽  
D. B. South ◽  
M. S. Golden ◽  
R. S. Meldahl

Abstract Loblolly pine (Pinus taeda L.) seedling height (measured immediately following planting) was significantly related to survival after two growing seasons. This relationship was negative on sites classified as adverse, with shorter seedlings having better survival than taller ones. Onnonadverse sites, taller seedlings survived as well or better than shorter seedlings. On all sites, initial height was inversely related to total seedling height growth during the first two seasons, permitting shorter seedlings at planting to reach the same total height as taller ones by agetwo. As a result, at age two, initial field height was not significantly related to total height. South. J. Appl. For. 11(3):139-143.


Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 803-807 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
Michelle M. Cram

A Longidorus species was consistently associated with patches of stunted and chlorotic loblolly pine seedlings at a forest-tree nursery in Georgia. Seedlings from affected areas had poorly developed root systems that lacked lateral and feeder roots. Longidorus population densities in composite soil samples from the margins of patches ranged from 9 to 67 nematodes per 100 cm3 of soil. In a growth chamber experiment, seedling root dry weight decreased with respect to the initial Longidorus dose as well as the final Longidorus populations in containers. The dry root weight of seedlings were 0.117, 0.090, 0.066, and 0.065 g in containers initially infested with 0, 50, 100, and 200 Longidorus, respectively. Lateral and fine roots were lacking on seedlings at the highest doses. Populations of Longidorus increased in all containers during the experiment. Damage to loblolly pine seedlings caused by Longidorus is a previously undescribed problem in southern pine nurseries. Proper diagnosis of the problem by nematode testing laboratories may require the use of extraction techniques specific for larger nematodes such as Longidorus.


1985 ◽  
Vol 15 (3) ◽  
pp. 586-592 ◽  
Author(s):  
John L. Ruehle

Loblolly (Pinustaeda L.), longleaf (Pinuspalustris Mill.), shortleaf (Pinusechinata Mill.), and eastern white (Pinusstrobus L.) pine seedlings inoculated with Pisolithustinctorius (Pers.) Coker & Couch (Pt) were raised in a greenhouse in containers painted with latex paint containing 50 g/L cupric carbonate (CuCO3). To determine the effects of CuCO3 on root development and morphology, seedlings were sampled in the middle and at the end of the test. The treatment was effective in preventing most first-order laterals of all species from growing down the container wall, yet it had no significant effect on seedling height, root-collar diameter, or top and root fresh weight. Cupric carbonate had little effect on ectomycorrhizal formation on loblolly and shortleaf seedlings, but significantly increased it on longleaf seedlings and decreased it on eastern white seedlings. Using CuCO3 to alter root morphology of containerized southern pine seedlings inoculated with Pt has the potential for developing stock that will grow long laterals near the soil surface for anchorage and increase the rate of spread of Pt ectomycorrhizae from the plug to new roots after planting.


1988 ◽  
Vol 12 (4) ◽  
pp. 234-239
Author(s):  
David B. South ◽  
R. J. Mitchell ◽  
R. K. Dixon ◽  
Mark Vedder

Abstract In July 1986, stunted loblolly pine (Pinus taeda L.) seedlings were studied at a nursery in Union Springs, Alabama. Stunted seedlings were found only in seedbeds formed on new ground (soil having no history of producing a nursery crop of ectomycorrhizal tree seedlings). The stunted seedlings were either nonmycorrhizal or had extremely low levels of ectomycorrhizae, whereas nonstunted seedlings had a greater degree of ectomycorrhizal development. Stunted seedlings were deficient in phosphorus (0.07%), whereas nonstunted seedlings had sufficient phosphorus (0.15%). An application of phosphoric acid (H3PO4) to stunted seedlings increased shoot phosphorus and resulted in substantial growth improvement. The phosphorus application reduced the percentage of cull seedlings (root-collar diameter <3.2 mm) from 62% to 8%. This study also demonstrates that when a seedbed is formed on new ground, ectomycorrhizal deficiencies can occur even when ectomycorrhizal tree hosts are present in the immediate vicinity. The ectomycorrhizal deficiency in the seedlings observed in this study may have been related to restricted spore dispersal caused by insufficient rainfall that had occurred after spring fumigation. South J. App. For. 12(4):234-239.


1980 ◽  
Vol 4 (3) ◽  
pp. 153-156
Author(s):  
John Talbert ◽  
Gordon White ◽  
Charles Webb

Abstract In a comparison of three diverse seed sources of improved Virginia pine (Pinus virginiana Mill.) planted at two locations in north Alabama and south-central Tennessee, only stem straightness differences were statistically significant at six years of age. Families and seed sources tended to maintain the same ranking relative to each other at both locations. A majority of families performed significantly better than a Virginia pine commercial check lot, indicating substantial improvement in growth and straightness characteristics in one generation of selection. Two improved loblolly pine (Pinus taeda L.) seed orchard mixes from the South Carolina Piedmont showed a 27-percent height advantage over the Virginia pine at age 6.


2001 ◽  
Vol 25 (1) ◽  
pp. 25-30
Author(s):  
William A. Carey ◽  
David B. South ◽  
M. Williford ◽  
J. Britt

Abstract Loblolly pine (Pinus taeda L.) seedlings were lifted from two nurseries in Georgia, and the roots were washed using equipment built for that purpose. Seedlings then received two levels of storage and were outplanted not far from the nursery of origin (one loam soil and one sandy soil). Immediately after washing, root weights and the length of fine roots did not differ among wash treatments from either nursery. Survival was excellent for all treatments on the loam soil, but a single wash reduced survival by 5 to 10% when seedlings were planted in sand. Washing slowed the rate of budbreak and early height growth. Bud growth of seedlings planted in a stress pit (containing sand) was correlated with both root growth 1 month after planting (r = 0.36,P = 0.0003) and survival 2 months after planting (r =0.62,P = 0.01). Among seedlings outplanted on a sandy site, initial height growth also correlated with survival (r = 0.49,P = 0.007). South. J. Appl. For. 25(1):25–30.


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