Growth and Xylem Water Potential of White Oak and Loblolly Pine Seedlings as Affected by Simulated Acidic Rain

1993 ◽  
Vol 129 (1) ◽  
pp. 26 ◽  
Author(s):  
R. F. Walker ◽  
S. B. McLaughlin
1996 ◽  
Vol 26 (10) ◽  
pp. 1715-1723 ◽  
Author(s):  
R.A. Reinert ◽  
S.R. Shafer ◽  
G. Eason ◽  
S.J. Horton ◽  
M.M. Schoeneberger

Acidic rain and ozone (O3) may have serious consequences on the growth and development of loblolly pine (Pinustaeda L.), a tree species of major economic importance in the southeastern United States. In two independent studies, seedlings of open-pollinated families of loblolly pine were exposed to five concentrations of O3 (0, 80, 160, 240, or 320 nL•L−1) and three simulated rain acidities (pH 5.3, 4.3, or 3.3). Following 23 weeks of growth (12 weeks in charcoal-filtered air and 11 weeks of O3 and simulated acidic rain exposures), stem height, secondary needle dry weight, top and total seedling dry weight, and root/shoot dry weight ratio all were related negatively and linearly with O3 concentration. Stem diameter and root dry weight were also suppressed by O3. Suppression of the growth parameters ranged from 14 to 35% for the greatest O3 concentration. Acidity of simulated rain did not affect seedlings, nor did it affect seedling responses to O3. Results indicate that acid rain probably has little effect on growth of loblolly pine seedlings, but O3 can suppress growth to varying degrees depending on family.


1994 ◽  
Vol 12 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Rick M. Bates ◽  
Alex X. Niemiera

Abstract Desiccation during storage and reestablishment is a major factor contributing to poor regrowth of transplanted bare-root trees. The effect of overhead mist irrigation on reducing post transplant water stress in Norway maple (Acer platanoides L. ‘Emerald Lustre’) and Yoshino cherry (Prunus x yedoensis) was examined. Bare-root Norway maple (desiccation tolerant) and Yoshino cherry (desiccation sensitive) trees were transplanted into pine bark-filled containers and subjected to mist or non-mist treatments. Stem xylem water potential, relative water content, and survivability were determined. Xylem water potential increased (became less negative) for misted maple and cherry trees. Water potential increased for non-misted maple and decreased for non-misted cherry trees. Twenty-seven percent of non-misted cherries were evaluated as nonmarketable due to stem dieback compared to 0% for misted trees. Results of this study indicate that mist irrigation effectively reduces desiccation damage for desiccation sensitive species such as cherries and hawthorns.


1990 ◽  
Vol 51 (1-2) ◽  
pp. 105-116 ◽  
Author(s):  
Woong S. Lee ◽  
Boris I. Chevone ◽  
John R. Seiler

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.


1988 ◽  
Vol 58 (10) ◽  
pp. 575-580 ◽  
Author(s):  
David N.-S. Hon

The mechanical stress energy used to process cotton in a cutter is sufficient to induce homolytic scission of C2 and C3 bonds and chain scission of C1—O—C4 glycosidic bonds, i.e., to reduce the degree of polymerization (DP), of cellulose molecules. The formation of carbon and alkoxy mechanoradicals at these locations was identified by an electron spin resonance study. The incorporation of nonylated phenol phosphite, hindered amine, and milled wood lignins of red oak and white oak was effective in inhibiting the reduction of the DP of cellulose. In addition, the incorporation of an alkylary phosphite mixture, hindered phenol, ditridecyl thiodipropionate and dialutyl thiodipropionate, milled wood lignin of loblolly pine and white oak, and lignosulfonate of spruce and red oak was useful in inhibiting the oxidative ageing of cut cotton fiber. Of the stabilizers used, only milled wood lignin of red oak was the most effective in preventing loss of the DP of cellulose during mechanical cutting and oxidative ageing. Termination of primary mechanoradicals at C2 and C3 by stabilizers appeared to eliminate secondary reactions that led to a subsequent decrease in the DP. Termination of alkoxy and carbon radicals at C4 and C1 positions appeared to eliminate oxidative degradation.


1996 ◽  
Vol 20 (1) ◽  
pp. 5-9 ◽  
Author(s):  
John C. Brissette ◽  
James P. Barnett ◽  
John P. Jones

Abstract Seedlings of loblolly and longleaf pine lifted in December, January, and February were treated with either benomyl or ridomil before cold storage. Along with an untreated control, they were planted after cold storage of less than 1 wk, 3 wk, and 6 wk. Survival was measured in mid-June after planting, and after 1 and 4 yr in the field. Total height was measured after 4 yr. The fungicide application increased survival of both species lifted in December or February and was beneficial to longleaf pine seedlings regardless of storage duration. Fungicide-treated longleaf pine seedlings had greater mean 4 yr height than the controls, but fungicides did not affect the height of loblolly pine. South. J. Appl. For. 20(1): 5-9.


Nematology ◽  
2012 ◽  
Vol 14 (4) ◽  
pp. 417-425 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
Michelle M. Cram ◽  
Zafar A. Handoo ◽  
Stanley J. Zarnoch

Tylenchorhynchus ewingi, a stunt nematode, causes severe injury to slash pine seedlings and has been recently associated with stunting and chlorosis of loblolly pine seedlings at some forest tree nurseries in southern USA. Experiments confirmed that loblolly pine is a host for T. ewingi, and that the nematode is capable of causing severe damage to root systems. Initial population densities as low as 60 nematodes (100 cm3 soil)−1 were sufficient to damage the root systems of loblolly pine seedlings. Populations of T. ewingi increased on pine from two- to 16-fold, depending on the initial population density. Evaluations of various cover crops used in southern forest tree nurseries indicated that legumes, rye and several varieties of sorghum were excellent hosts for T. ewingi. Other small grains such as ryegrass, oats and wheat were poorer hosts. A cultivar of pearl millet was a non-host for T. ewingi, and a cultivar of brown top millet appeared to be either a very poor host or a non-host. Nurseries that have seedling production losses caused by T. ewingi should consider rotating with non-host cover crops such as pearl millet or leaving fields fallow as part of their pest management programme.


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