Ethylene production by loblolly pine seedlings associated with water stress

1987 ◽  
Vol 69 (1) ◽  
pp. 167-172 ◽  
Author(s):  
Nancy J. Stumpff ◽  
Jon D. Johnson
1993 ◽  
Vol 23 (9) ◽  
pp. 1810-1814
Author(s):  
Douglas M. Stone

Curly shaped needles developed on loblolly pine (Pinustaeda L.) seedlings grown in lysimeters in two greenhouse studies. Nearly 80% of the seedlings from five half-sib families developed curly needles when watered weekly with one of four acid rain solutions. No abnormal needles developed on seedlings from the same seed lots growing on an adjacent bench and watered daily. In a second study, curly needles developed within 2 weeks after seedlings were transplanted into the lysimeters. Weekly misting of the foliage significantly reduced the proportion of fascicles with curly needles. Results indicate that curly needle syndrome is induced by water stress during needle elongation and suggest that wetting the foliage decreases the strength of the fascicle sheaths.


1984 ◽  
Vol 62 (10) ◽  
pp. 2135-2139 ◽  
Author(s):  
Leslie C. Tolley ◽  
B. R. Strain

Mathematical growth analysis techniques were used to assess the possible interactive effects of atmospheric carbon dioxide enrichment and water stress on growth and biomass partitioning of Liquidambar styraciflua L. (sweetgum) and Pinus taeda L. (loblolly pine) seedlings. Plants were grown from seed under 1000 μmol∙m−2∙s−1 photosynthetic photon flux density at CO2 concentrations of 350, 675, and 1000 μL∙L−1 for 56 days. At this time, half the seedlings in each CO2 treatment had water withheld until plant water potentials reached about −2.5 MPa in the most stressed plants, while the remaining plants were well watered. At the end of the drying cycle, stressed plants were returned to well-watered conditions for a 14-day recovery period. The greatest effects of water stress on growth were seen following the recovery period and were most severe for sweetgum seedlings grown at the lowest CO2 concentration. For sweetgum seedlings in particular, the reduction of early seedling growth following exposure to a period of drought under normal atmospheric CO2 concentration was ameliorated by growing plants under elevated CO2, primarily because of maintenance of greater net assimilation rates following a period of stress. The data presented here suggest that a doubling of atmospheric CO2 concentration would enable sweetgum seedlings to become established in drier sites which are currently dominated by loblolly pine seedlings.


2017 ◽  
Vol 47 (10) ◽  
pp. 1364-1371 ◽  
Author(s):  
Joshua C. Bradley ◽  
Rodney E. Will

Hybridization between shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.) has dramatically increased and may threaten the genetic integrity of shortleaf pine. Shortleaf pine is presumed to be more drought tolerant than loblolly pine, but the drought hardiness of the hybrid pine is not known. We determined biomass partitioning in response to water stress and measured whole-plant transpiration of shortleaf, loblolly, and hybrid pine seedlings. Water stress decreased total seedling biomass, increased biomass partitioning to foliage, and decreased biomass partitioning to coarse roots. Shortleaf pine seedlings partitioned more biomass to coarse roots than loblolly pine, and hybrid pine was intermediate between the parent species. We found no differences in the level of soil moisture at which seedlings of different species began to limit transpiration. Our results suggest that the transpiration response of shortleaf pine and hybrid pine is similar to that of loblolly pine when exposed to water stress. However, greater partitioning to coarse root may allow shortleaf and hybrid pines to better withstand drought due to greater potential belowground carbohydrate supply.


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.


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