Changes in freezing tolerance, plasma membrane H+-ATPase activity and fatty acid composition in Pinus resinosa needles during cold acclimation and de-acclimation

Abstract

It has previously been suggested that plasma membrane ATPase (PM H+-ATPase, EC 3.6.1.3.) is a site of incipient freezing injury because activity increases following cold acclimation and there are published data indicating that activity of PM H+-ATPase is modulated by changes in lipids associated with the enzyme. To test and extend these findings in a tree species, we analyzed PM H+-ATPase activity and the fatty acid (FA) composition of glycerolipids in purified plasma membranes (PMs) prepared by the two-phase partition method from current-year needles of adult red pine (Pinus resinosa Ait.) trees. Freezing tolerance of the needles decreased from -56 degrees C in March to -9 degrees C in May, and increased from -15 degrees C in September to -148 degrees C in January. Specific activity of vanadate-sensitive PM H+-ATPase increased more than two-fold following cold acclimation, despite a concurrent increase in protein concentration. During de-acclimation, decreases in PM H+-ATPase activity and freezing tolerance were accompanied by decreases in the proportions of oleic (18:1) and linoleic (18:2) acids and increases in the proportions of palmitic (16:0) and linolenic (18:3) acids in total glycerolipids extracted from the plasma membrane fraction. This pattern of changes in PM H+-ATPase activity and the 18:1, 18:2 and 18:3 fatty acids was reversed during cold acclimation. In the PM fractions, changes in FA unsaturation, expressed as the double bond index (1 x 18:1 + 2 x 18:2 + 3 x 18:3), were closely correlated with changes in H+-ATPase specific activity (r2 = 0.995). Changes in freezing tolerance were well correlated with DBI (r2 = 0.877) and ATPase specific activity (r2 = 0.833) in the PM fraction. Total ATPase activity in microsomal fractions also closely followed changes in freezing tolerance (r2 = 0.969). We conclude that, as in herbaceous plants, simultaneous seasonal changes in PM H+-ATPase activity and fatty acid composition occur during cold acclimation and de-acclimation in an extremely winter hardy tree species under natural conditions, lending support to the hypothesis that FA-regulated PM H+-ATPase activity is involved in the cellular response underlying cold acclimation and de-acclimation.

Fertilisation automnale des plants de Pinus resinosa : absorption des éléments nutritifs, rusticité au froid, et développement morphologique

“…Extreme winter temperatures at north-central Minnesota are severe and could decline to -46 • C, suggesting that seedlings grown from local seed sources are well adapted to such low temperatures. Martz et al (2006) reported a LT 50 (i.e., test temperature that causes injury or death to 50% of the test population) of -148 • C for red pine needles measured in January following cold acclimation, but they visually estimated the extent of needle freezing injury (i.e., browning). Furthermore, Sutinen et al (1992) found that electrolyte leakage of red pine needles never exceeded 30% when needles were exposed to -80 • C or lower temperatures or subjected to a slow Improved N concentration of fall fertilized seedlings may have provided necessary resources for seedlings to increase the amount of organic compounds, such as amino acid or other organic acids, which woody plants accumulate when exposed to low temperatures (Kontunen-Soppela (2001).…”

“…Two-year-old seedlings were sampled similarly. For each fertilizer treatment replication, a sufficient number of needles from 5 seedlings (following Martz et al, 2006) were obtained and cut into approximately 1-cm segments. From each group of 5 seedlings, 7 segments were placed into 7 separate vials (each vial corresponding to different test temperatures: 2 [control], -5, -10, -20, -25, -30, and -40 • C).…”

“…The present fall fertilization study was undertaken primarily to determine the potential to augment second year height growth of 2 + 0 red pine seedlings without compromising cold hardiness. A limited number of published studies (e.g., Martz et al, 2006;Sutinen et al, 1992) have examined cold tolerance of red pine, but none investigated effects of fall fertilization on corresponding cold hardiness. Our study objectives were to evaluate if fall fertilization applied at the end of the first growing season would: (i) increase the number of needle primordia, resulting in greater shoot elongation and biomass in the following season; and (ii) affect cold hardiness as measured by freeze-induced electrolyte leakage (FIEL).…”

Plant Plasma Membrane H+-ATPase in Adaptation of Plants to Abiotic Stresses

“…The activation of H + -ATPase is dependent on the degree of saturation or unsaturation of the fatty acyl chain and its length. The activity decreased with an increase in the length of the fatty acyl chain and in the degree of unsaturation of fatty acid (Hernandez et al, 2002;Kasamo, 2003, Martz et al, 2006. Lysophosphatidylcholine (a natural detergent produced from phosphatidylcholine by phospholipase A 2 ) increased the plasma membrane H + -ATPase activity (Pedechenko et al, 1990, Regenberg et al, 1995.…”

“…In broccoli plants a high degree of unsaturation in the plasma membrane of roots was observed (López-Pérez et al, 2009). The activity of plant plasma membrane H + -ATPase increased with an increase in the degree of unsaturation of fatty acid (Kasamo, 2003, www.intechopen.com Martz et al, 2006). Non-tolerant plants subjected to salt stress commonly show decreased levels of 18:3 in their membranes (Upchurch, 2008).…”