Root Stripping Reduces Root Growth Potential Of Loblolly Pine Seedlings

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.

1988 ◽  
Vol 12 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Harry S. Larsen ◽  
David B. South ◽  
James N. Boyer

Abstract Height growth of outplanted loblolly pine seedlings was monitored over a 3-year period. Growth of seedlings from 20 nurseries was correlated with initial seedling characteristics from paired samples. Height growth during the first 6 months after planting was negatively correlated with the initial seedling height and shoot/root ratio and was positively correlated with root growth potential (RGP) and root weight. However, these variables were not significantly correlated with later growth. Foliar nitrogen content (mg of foliar nitrogen per seedling) was positively correlated with both initial and subsequent field growth. Foliar nitrogen content was the only variable that was significantly correlated with diameter growth and volume growth during the third year after planting. This variable accounted for 36% of the variation among sample means for 3-year height growth. These data support a previous report that field performance of loblolly pine seedlings during the first 3 years in the field can be influenced by the foliar nitrogen content at lifting. South. J. Appl. For. 12(3):181-185.


1986 ◽  
Vol 10 (1) ◽  
pp. 24-27 ◽  
Author(s):  
Peter P. Feret ◽  
Richard E. Kreh

Abstract Loblolly pine seedlings undercut using five different treatments extending from July to September exhibited significant alteration of shoot and root biomass. Root growth potential (RGP) (measured by number of new elongating roots) was not significantly altered by undercutting. Undercutting did significantly alter the RGP/root weight ratio and the RGP/shoot weight ratio because of both concomitant changes in root and shoot biomass and changes in seedling physiology. Root growth potential and efficiency of existing old roots to produce new roots were not well correlated with seedling size.


New Forests ◽  
1990 ◽  
Vol 4 (3) ◽  
pp. 179-192 ◽  
Author(s):  
David B. South ◽  
Harry S. Larsen ◽  
James N. Boyer ◽  
Hans M. Williams

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.


1994 ◽  
Vol 18 (1) ◽  
pp. 19-23
Author(s):  
David B. South ◽  
Nancy J. Loewenstein

Abstract A mixture of clay and benomyl is registered for use on longleaf pine (Pinus palustris Mill.) to control diseases and increase outplanting survival. However, for one sandy site in Alabama, treating roots with a gel slurry of Viterra containing benomyl reduced survival of stored seedlings when compared to a clay slurry containing benomyl (2.5% active ingredient). Root growth potential for January-lifted seedlings was also reduced by adding benomyl to a Viterra gel. For this study, seedlings planted in January and mid-February had better survival than seedlings planted in December or March. Poor survival in December resulted when seedlings were planted 2 wk prior to a hard freeze. South. J. Appl. For. 18(1):19-23.


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.


2013 ◽  
Vol 61 (8) ◽  
pp. 600 ◽  
Author(s):  
Erin Griffiths ◽  
Jason C. Stevens

Limited success of restoring framework banksia-woodland species has been attributed to the failure of seedlings to establish deep root systems before the onset of the summer drought. The present glasshouse study investigated how optimising nutrient application during nursery production may increase new-root production after outplanting. Two experimental streams were established to (1) optimise nutrient application rates during nursery production and (2) utilise nutrient-loading techniques to improve root production of Banksia menziesii R.Br., Banksia attenuata R.Br. and Eucalyptus todtiana F.Muell after outplanting. Optimal nutrient-application rates were determined by measuring plant growth and internal nutrient responses to eight application levels of slow-release fertiliser (0–18 kg m–3, nitrogen (N) : phosphorus (P) : potassium (K) = 17 : 1.6 : 8.7). Nutrient-loading treatments utilised seedlings that had been grown under common industry fertiliser conditions (3 kg m–3 native Osmocote, N : P : K = 17 : 1.6 : 8.7) supplied with ‘low’ or ‘high’ loading doses of liquid Thrive continuously over 6 weeks, immediately before outplanting. Seedlings from both experiments were then outplanted to 1-m-deep poly-pipe tubes containing habitat soil. After 12 weeks, plants were harvested and new-root production and shoot growth were measured. Optimal concentrations of slow-release fertiliser for maximum outplanting success as indicated by increased root investment (root : shoot ratio and new-root production) were 8–12 kg m–3 for all species. Nutrient loading increased N and P concentrations of plants by up to 80% and 127%, respectively, by luxury nutrient consumption, and after planting, nutrient-loaded seedlings produced 1.5-fold the biomass of conventionally fertilised seedlings, this being the result of greater root productivity. In conclusion, optimising nursery nutrient regimes for framework species may increase root-growth potential, assisting in improving plant establishment in restoration programs.


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