Effect of bud status and seedling biomass on root growth potential of loblolly pine

1988 ◽  
Vol 18 (12) ◽  
pp. 1635-1640 ◽  
Author(s):  
Hans M. Williams ◽  
David B. South ◽  
Glenn R. Glover
Keyword(s):  
Root Growth ◽  
Loblolly Pine ◽  
Dry Weight ◽  
Shoot Tip ◽  
Growth Potential ◽  
Root Growth Potential ◽  
Seedling Size ◽  
Covariate Analysis ◽  
Terminal Bud ◽  
Terminal Buds

Container-grown seedlings of Pinustaeda L. with well-formed terminal buds, feather-tops (a succulent shoot tip crowned with a tuft of primary needles), and terminal buds removed (debudded) were sampled in November, December, and January. Root growth potential for unstored and stored seedlings was measured to determine if it is affected by shoot tip morphology. Seedlings with buds or debudded seedlings had higher root growth potential than feather-top seedlings. Root growth potential was correlated with several morphological variables, including total ovendry weight (r = 0.81). As feather-top seedlings were smaller in diameter and biomass, a covariate analysis (using seedling dry weight as a covariate) was conducted. The covariate analysis indicated that differences in root growth potential between shoot types could be accounted for by differences in seedling size. The percentage of seedlings resuming growth and the total amount of new shoot growth during the test of root growth potential showed that feather-top seedlings and seedlings with terminal buds respond similarly to chilling temperatures. These results indicate that seedling size is more important than the presence of a well-formed terminal bud when seedlings are graded before outplanting.

Effect of Undercutting on Loblolly Pine Seedling Size and Its Relation to Root Growth Potential

1986 ◽  
Vol 10 (1) ◽  
pp. 24-27 ◽  
Author(s):  
Peter P. Feret ◽  
Richard E. Kreh
Keyword(s):  
Root Growth ◽  
Loblolly Pine ◽  
Weight Ratio ◽  
Growth Potential ◽  
Shoot Biomass ◽  
Root Weight ◽  
Root Growth Potential ◽  
Seedling Size ◽  
Seedling Physiology ◽  
Shoot Weight

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.

Seed spacing and seedling biomass: Effect on root growth potential of loblolly pine (Pinus taeda)

New Forests ◽  
1990 ◽  
Vol 4 (3) ◽  
pp. 179-192 ◽  
Author(s):  
David B. South ◽  
Harry S. Larsen ◽  
James N. Boyer ◽  
Hans M. Williams
Keyword(s):  
Root Growth ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Growth Potential ◽  
Root Growth Potential ◽  
Seedling Biomass ◽  
Seed Spacing

Carbohydrate reserves and root growth potential in Douglas-fir seedlings before and after cold storage

1982 ◽  
Vol 12 (4) ◽  
pp. 905-912 ◽  
Author(s):  
Gary A. Ritchie
Keyword(s):  
Root Growth ◽  
Cold Storage ◽  
Drought Resistance ◽  
Dry Weight ◽  
Douglas Fir ◽  
Growth Potential ◽  
Frost Hardiness ◽  
Root Growth Potential ◽  
Carbohydrate Reserves ◽  
Before And After

Carbohydrate reserves and root growth potential (RGP) of 2 + 0 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were monitored through a lifting season and during dark, cold storage. Concentrations of total nonstructural carbohydrate and extractable sugars in root and stem tissues remained relatively constant through winter, while foliar sugars showed a sharp midwinter peak at about 195 mg•g−1 dry weight. RGP was lowest in November and March and peaked in January. During storage at +2 and −1 °C, carbohydrates were depleted in all tissues through respiratory consumption. In contrast, RGP increased during the first 6 months in storage and then fell rapidly. The results do not support the view that changes in RGP are driven by changes in carbohydrate concentrations. Storage may affect frost hardiness and drought resistance through its effect on sugar concentrations.

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
Keyword(s):  
Root Growth ◽  
Loblolly Pine ◽  
Relative Effect ◽  
Growth Potential ◽  
Root Weight ◽  
Root Growth Potential ◽  
Root Shoot Ratio ◽  
Pine Seedlings ◽  
Pinus Taeda L ◽  
Root Apices

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.

Changes in loblolly pine root growth potential from September to April

1987 ◽  
Vol 17 (7) ◽  
pp. 635-643 ◽  
Author(s):  
Laura E. DeWald ◽  
Peter P. Feret
Keyword(s):  
Root Growth ◽  
Loblolly Pine ◽  
Environmental Changes ◽  
Lateral Roots ◽  
Root Systems ◽  
Shoot Elongation ◽  
Growth Potential ◽  
Late Winter ◽  
Root Growth Potential ◽  
Shoot Phenology

Loblolly pine (Pinustaeda L.) 1 + 0 seedlings were periodically hand lifted from a Virginia nursery to determine how root growth potential (RGP) varied between September and April. Several seedling characteristics, RGP, and shoot phenology were recorded for each lift date in 1983–1984 and 1984–1985. An attempt was made to relate RGP variation to changes in the nursery environment and to shoot phenology. Root growth potential variation was consistent between years and was more closely related to shoot phenological changes than to short-term environmental changes. During the development of dormancy, RGP was low, RGP increased when shoot activity resumed during the RGP tests (late winter, early spring), and declined as active shoot elongation began in the nursery. When RGP was low, elongation of existing lateral roots primarily contributed to the new root systems, but as seedling metabolism increased in the late winter, new root initiation also contributed to new root systems. Absolute differences in RGP between years may be related to the fibrosity of seedling root systems.

Root Growth Potential, First-Year Survival, and Growth of Shortleaf Pine Seedlings Show Effects of Life Date, Storage, and Family

1989 ◽  
Vol 13 (4) ◽  
pp. 163-169 ◽  
Author(s):  
S. W. Hallgren ◽  
C. G. Tauer
Keyword(s):  
Root Growth ◽  
Seedling Survival ◽  
Lateral Roots ◽  
Growth Potential ◽  
First Year ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Root Growth Potential ◽  
Terminal Bud ◽  
Survival And Growth

Abstract Root growth potential (RGP), and first-year field survival and growth of shortleaf pine (Pinus echinata Mill.) seedlings were significantly affected by lift date, storage, and family. Seedlings lifted in December and January showed highest RGP, survival, and growth. Storage for 28 daysalways reduced survival and growth, and the effect was greatest for late-lifted seedlings. However, for late planting, the difference in performance between freshly lifted seedlings and earlier lifted and stored seedlings may be small. Large family differences existed for seasonal changesin RGP and survival, suggesting separate management by family may be beneficial. The presence of a terminal bud and secondary needles showed little value in predicting seedling performance, whereas RGP and number of primary lateral roots were strongly correlated with seedling survival. South.J. Appl. For. 13(4):163-169.

Influence of nursery culture on growth, cold hardiness, and drought resistance of yellow cypress

1993 ◽  
Vol 23 (12) ◽  
pp. 2537-2547 ◽  
Author(s):  
J.T. Arnott ◽  
S.C. Grossnickle ◽  
P. Puttonen ◽  
A.K. Mitchell ◽  
R.S. Folk
Keyword(s):  
Root Growth ◽  
Drought Resistance ◽  
Cold Hardiness ◽  
Shoot Growth ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Moisture Stress ◽  
Growth Potential ◽  
Root Growth Potential ◽  
Short Day

The influence of short-day (9 h) and long-day photoperiods (18 h), and three levels of plant moisture stress (none and dried to predawn shoot water potentials of −1.0 or −1.8 MPa), applied for 7 weeks beginning in mid-July 1990, were studied on greenhouse-grown stecklings (rooted cuttings) of yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach). A series of morphological and physiological measurements were made on the stecklings during and after the treatment period. Moisture stress significantly reduced steckling shoot growth and shoot dry weight by lowering net photosynthesis rates, while short-day photoperiods did not. The most pronounced growth reductions occurred when the treatments were combined, but effects were short-lived, with shoot growth resuming soon after the treatments ended. The short-day and moisture-stress treatment had no significant effect on root dry weight, shoot/root ratio, or water balance ratio. The risk of using moisture stress to control shoot growth in the nursery was low; mortality did not occur until the stecklings had been without water for at least 9 days. Moisture-stress treatments increased steckling root growth potential but had little effect on osmotic adjustment, cell elasticity, dry weight or symplastic fractions, cuticular transpiration, resistance to plant water movement, and relative water content of the shoots; short-day treatments had no influence on any of these parameters. Short days and moisture stress, singly or combined, had little effect on steckling cold hardiness. Steckling gas exchange rates were reduced significantly by low root temperature. In a 6-week controlled-environment simulation of planting-site moisture conditions, no significant differences in steckling net photosynthesis, transpiration, or stomatal conductance were found among nursery treatments; those that had been subjected to moisture stress in the nursery had small growth increases after planting in both wet and dry soil moisture regimes. We conclude that shoot growth of yellow cypress stecklings was controlled in the nursery using 9-h photoperiods and −1.8 MPa predawn shoot water potentials. Improved cold hardiness of the stecklings was not achieved using these nursery cultural methods, but moisture stress did confer some measure of drought resistance immediately after treatment, with higher root growth potential and lower shoot mass.

Root growth potential and bud dormancy of 2 + 0 eastern white pine grown in a Virginia nursery

1989 ◽  
Vol 19 (12) ◽  
pp. 1598-1602
Author(s):  
Kurt H. Johnsen ◽  
Peter P. Feret ◽  
John R. Seiler
Keyword(s):  
Root Growth ◽  
Growth Potential ◽  
Bud Dormancy ◽  
Dormancy Release ◽  
White Pine ◽  
Eastern White Pine ◽  
Root Growth Potential ◽  
Terminal Bud ◽  
Chilling Hours ◽  
The Relationship

Root growth potential and dormancy release index were examined over 2 years using 2 + 0 eastern white pine seedlings grown in a Virginia nursery. Root growth potential patterns were quite different between years. The relationship between dormancy release index and chilling sums (0–7 °C) was consistent between years. Approximately 2800 chilling hours were necessary to break terminal bud dormancy fully. There was a highly significant, positive linear relationship between root growth potential and dormancy release index above a dormancy release index of 0.20 when 2 years data were combined. For dormancy release index values <0.20, the relationship between root growth potential and dormancy release index was inconsistent between years.

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