Electrolyte leakage from fine roots of conifer seedlings: a rapid index of plant vitality following cold storage

1992 ◽  
Vol 22 (9) ◽  
pp. 1371-1377 ◽  
Author(s):  
H.M. McKay

Two-year-old Sitka spruce (Piceasitchensis (Bong.) Cam), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and Japanese larch (Larixleptolepis (Sieb. & Zucc.) Gord.) were cold-stored at 1 °C for 1 to 6 months. In April at the end of the cold storage period, root growth potential and electrolyte leakage from the fine roots were assessed and related to plant survival and height growth. After cold storage, seedlings were planted on a second-rotation, cultivated site. In two experiments planted in 1989 and 1990, fine-root electrolyte leakage was closely correlated with survival and height growth. Fine-root leakage has also practical advantages over other available methods of assessing plant vitality after cold storage.

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 (3) ◽  
pp. 337-342 ◽  
Author(s):  
H.M. McKay

Fine-root electrolyte leakage from 2-year-old planting stock of three conifer species was measured on 13 dates between October 1989 and April 1990. The three species (Piceasitchensis (Bong.) Carr., Pseudotsugamenziesii (Mirb.) Franco, and Larixleptolepis (Sieb. & Zucc.) Gord.) were raised using either transplanting or undercutting and wrenching regimes. On each lifting date, excised fine roots were stored at 1 °C for 30 and 90 days. The deterioration of the fine roots was assessed by comparing electrolyte leakage values before and after storage. As the lifting date progressed from October to mid-December all three species became less adversely affected by storage, indicating that roots undergo physiological changes that increase their tolerance to prolonged cold storage. The interaction between lifting date and storage duration on fine-root quality differed in the three species. For example, Piceasitchensis could tolerate 90 days' storage commencing at any time from mid-December till early April with negligible root damage. Pseudotsugamenziesii could not tolerate 90 days' storage at any time of year, and tolerance to 30 days' storage was limited and could be substantially reversed. Fine roots of Larixleptolepis were only slightly damaged after 90 days' storage beginning from mid-November to the end of December.


2005 ◽  
Vol 35 (10) ◽  
pp. 2413-2422 ◽  
Author(s):  
Raquel Cabral ◽  
Conor O'Reilly

The effects of warm storage (15 °C) on the physiological responses and subsequent field performance of 2-year-old oak (Quercus robur L.) seedlings that had been cold (1–2 °C) stored until May were assessed. Shoot xylem pressure potential, shoot water content, shoot tip dry mass, root electrolyte leakage, and root growth potential were evaluated at regular intervals during the 21-day warm storage period. The date of lifting to cold storage had little effect on the physiological responses to warm storage. Root electrolyte leakage increased after 7 days of storage, despite the fact that root growth potential and survival were unaffected. Values then increased further before decreasing again by the end of the 21-day storage period to values similar to those recorded after 0 or 7 days of storage. Storage for up to 21 days greatly reduced root growth potential and shoot quality after planting in the field. The shoot xylem pressure potential of seedlings declined during the early stage of warm storage, but then increased to values similar to those recorded after cold storage. Shoot water content increased during the early storage period, then declined slightly, but values were higher after 21 days of storage than at the time of placement in warm storage. While most physiological responses fluctuated in a consistent manner, these changes were not necessarily predictable. Root growth potential was a good indicator of plant field performance potential, but the other physiological parameters were less useful to this end.


2009 ◽  
Vol 27 (4) ◽  
pp. 229-233 ◽  
Author(s):  
Gary W. Watson

Abstract Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.


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.


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.


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.


2012 ◽  
Vol 77 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Joanna Chojak ◽  
Elżbieta Kuźniak ◽  
Urszula Świercz ◽  
Joanna Sekulska-Nalewajko ◽  
Jarosław Gocławski

Summary We studied the effects of sequentially applied salt stress and Pseudomonas syringae pv lachrymans (Psl) infection in cucumber (Cucumis sativus L.). Infection development, shoot and root growth potential, the concentrations of chlorophyll and proline as well as electrolyte leakage, lipid peroxidation and H2O2 production were determined. Cucumber plants were first exposed to salt stress and irrigated for seven days with 50 or 100 mM NaCl and thereafter inoculated by Psl. Abiotic stress compromised the defence response to pathogen and disease severity was the highest in 100 mM NaCl-treated plants. The reduced performance of salinized plants under biotic stress could be related to salt stressinduced plant growth inhibition with leaf expansion being the most sensitive to salinity, decreased chlorophyll content, increased electrolyte leakage and prolonged H2O2 accumulation in leaves implying perturbations in redox homeostasis. The response of NaCl-treated and control plants to bacterial infection differed in terms of H2O2 generation and lipid peroxidation. This study confirmed that proline is an important component of local and systemic responses to salt stress and infection. The results contribute to our knowledge of the nature of plant response to a combination of abiotic and biotic stresses


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