Sitka Spruce and Douglas fir Seedlings in the Nursery and in Cold Storage: Root Growth Potential, Carbohydrate Content, Dormancy, Frost Hardiness and Mitotic Index

1990 ◽  
Vol 63 (1) ◽  
pp. 9-27 ◽  
Author(s):  
M. G. R. CANNELL ◽  
P. M. TABBUSH ◽  
J. D. DEANS ◽  
M. K. HOLLINGSWORTH ◽  
L. J. SHEPPARD ◽  
...  
1982 ◽  
Vol 12 (4) ◽  
pp. 905-912 ◽  
Author(s):  
Gary A. Ritchie

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.


1986 ◽  
Vol 16 (6) ◽  
pp. 1385-1388 ◽  
Author(s):  
Paul M. Tabbush

Sealed bags containing forty 2-year-old Sitka spruce (Piceasitchensis (Bong.) Carr.) transplants were dropped 1–15 times from a height of 3 m onto a hard floor. A single drop reduced root growth potential of the plants as measured by a 10-day test, although after 18 days' growth the effect was no longer detectable. Dropping the bags 5 or 15 times severely decreased root growth potential even in the 18-day test. The 15-drop treatment significantly depressed 1-year survival of samples planted in the nursery. Sitka spruce and Douglas-fir (Pseudotsugamenziesii fMirb.) Franco.) transplants dropped 10 times, together with control plants, were placed in root observation boxes with an air temperature of 8 °C and a soil temperature of 4, 8, 12, or 16 °C. At 4 °C soil temperature, little or no root growth was observed in either species. At the higher temperatures the total numbers of new roots formed in 10 days and the number of new roots greater than 1 cm in length formed in 18 days were generally greater in Sitka spruce than Douglas-fir. In both species, root growth was sharply reduced by the mechanical shock treatment. Dropping the trees also depressed mycorrhizal development and resulted in a significant lowering of predawn water potential in Douglas-fir.


1990 ◽  
Vol 63 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. D. DEANS ◽  
C. LUNDBERG ◽  
M. G. R. CANNELL ◽  
M. B. MURRAY ◽  
L. J. SHEPPARD

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 597
Author(s):  
Jacob A. Reely ◽  
Andrew S. Nelson

Environmental conditions and seedling quality interact to produce complex patterns of seedling survival and growth. Root growth potential (RGP) is one metric of seedling quality that can be rapidly measured prior to planting, but the correlation of RGP and seedling performance is not consistent across studies. Site factors including microsite objects that cast shade and competing vegetation can also influence seedling performance. We examined the effects of RGP, presence/absence of a microsite object, and competition cover on the survival and growth of three native conifers to the Inland Northwest, USA, over 5 years. We found that RGP had no effect on the survival or growth of western larch (Larix occidentalis), Douglas fir (Pseudotsuga menziesii var. glauca), and grand fir (Abies grandis) at a mesic north aspect site and a xeric south aspect site. Comparatively, the presence of a microsite increased the odds of survival by 37% for western larch and 158% for grand fir, while the absence of forb cover increased the odds of survival of western larch by 72% and of grand fir by 26%. Douglas fir was less sensitive to microsites and competition. The strong effects of neighborhood conditions around seedlings help inform silvicultural practices to enhance the establishment of western larch and grand fir, including planting seedlings near shading objects and competition control, while these practices may not be as important for Douglas fir.


1991 ◽  
Vol 21 (6) ◽  
pp. 890-901 ◽  
Author(s):  
H. M. McKay ◽  
W. L. Mason

Two-year-old transplants and undercuts of Piceasitchensis (Bong.) Carr. and Pseudotsugamenziesii (Mirb.) Franco were cold-stored (1 °C) for 1 to 7 months ending in April 1989. Their physiological arid morphological condition at lifting and after storage was assessed and related to survival and height increment on a reafforestation site after one growing season. Physiological assessments made between October and April at lifting were root growth potential, tolerance of fine roots to chronic cold, shoot and root mitotic index, root elongation, and electrolyte leakage from the shoot and roots. Shoot cold hardiness was assessed between October and mid-December. The seasonal changes in these parameters and the effect of species and undercutting treatments are described. At lifting, root growth potential identified (i) differences due to species and undercutting treatments and (ii) the earliest possible safe lifting dates of P. menziesii but not of P. sitchensis. After cold storage, plant vigour was assessed by root growth potential and shoot and root membrane integrity. Membrane integrity of the fine roots was a very good indicator of survival. There was a highly significant, negative correlation between the rate of electrolyte leakage, indicating membrane damage, and survival (p ≤ 0.001, r = −0.90).


1993 ◽  
Vol 23 (11) ◽  
pp. 2443-2451 ◽  
Author(s):  
H.M. McKay ◽  
B.A. Gardiner ◽  
W.L. Mason ◽  
D.G. Nelson ◽  
M.K. Hollingsworth

Two-year-old Sitka spruce (Piceasitchensis (Bong.) Carr.) seedlings were lifted from the nursery at different times of the year and subjected to known forces by dropping bags of plants from a height of 10, 100, or 300 cm onto a concrete floor for a varying number of times (0 to 135). The response of the seedlings to dropping was assessed by their growth and survival in field experiments, root growth potential, root electrolyte leakage, and triphenyl tetrazolium chloride reduction. The forces were measured by attaching an accelerometer linked to an oscilloscope to the root collar of trees in the centre of each bag. Typically the forces generated by a 10-cm drop were about 11 g, while those generated by a 300-cm drop were about 140 g. All seedlings lifted in mid-February and mid-March survived one growing season in a cultivated, weed-free nursery soil, but height growth was significantly reduced by 300-cm drops. The survival of seedlings lifted in August was reduced by 5 and 15 drops particularly from 300 cm. Root growth potential was decreased while electrolyte leakage and triphenyl tetrazolium chloride reduction activity of the fine roots 2 days after dropping were increased by dropping. Growth and physiological differences associated with dropping were more closely and frequently correlated with the maximum force exerted than to the mean or the total force.


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