Tolerance of conifer fine roots to cold storage

Abstract

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.

Appraisal of root leakage as a method for estimation of root viability

“…REL decreased in Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings from early autumn to mid-winter (McKay, 1993(McKay, , 1994O'Reilly et al, 2000). REL of sycamore (Acer pseudoplatanus L.) seedlings, growing in Ireland, declined from 61% in early October to 16% and 18% in January and February, respectively (Mortazavi et al, 2004).…”

“…During the over-wintering period, REL varies among tree species (McKay, 1992(McKay, , 1993. This may be due to different seed sources, different nursery environments, and different cultural Oak roots were previously exposed to four desiccation treatments with durations of 0, 4, 6, and 8 h, according to the methodology outlined in Mortazavi et al (2004).…”

“…The origins of REL test can be traced back to the early work of Wilner (1955Wilner ( , 1960, but McKay and her collaborators were among the first who used REL to assess the survival potential of bare-root nursery stock (McKay & Mason, 1991;McKay, 1993;. The method is based on the fact that in healthy tissues, a high symplastic electrolyte concentration is maintained either by selective transmittance across the membranes or by active transport by cell membrane proteins (Palta et al, 1977).…”

“…REL has been used to detect and quantify damage in conifer seedlings following cold storage (Mason & McKay, 1990;McKay, 1992McKay, , 1993 after rough handling and desiccation (McKay et al, 1993;McKay & White, 1997) and after exposure to freezing temperatures (Bigras & D'Aoust, 1992;McKay, 1993;Bigras & Calmé, 1994;Colombo, 1994;Bigras, 1997). The use of the method for this purpose is based on the assumption that the aforementioned stressors affect the permeability of the cell plasma membranes.…”

Effect of desiccation on the root system of Norway spruce (Picea abies [L.] Karst.) seedlings and a possibility of using hydrogel STOCKOSORB^®for its protection

“…This injury was caused by desiccation (FAN, BLAKE 1994;SARVAŠ 1998SARVAŠ , 2002. Some authors used these measurements: a) to determine lifting dates for barerooted seedlings (MCKAY 1992(MCKAY , 1993(MCKAY , 1994(MCKAY , 1998MCKAY, MASON 1991;MCKAY, MORGAN 2001, etc. ), b) to assess frost damage to trees and to determine the levels of frost hardiness (BIGRAS, COLOMBO 2001;COLOMBO 1994COLOMBO , 1997ÖGREN 2001;NICOLL et al 1996;SARVAŠ 2001, etc), and c) heat damage (BINDER, FIELDER 1995).…”