An heuristic hypothesis of chilling injury in plants: a role for calcium as the primary physiological transducer of injury

Abstract

Abstract. It is suggested that increased levels of free cytosolic calcium ([Ca2+]cyt) may serve as the primary physiological transducer of chilling injury in plants. Numerous similarities between the effects of [Ca2+]cyt‐raising treatments on plants and the effects of chilling temperatures on chilling‐sensitive (CS) plants are noted. It is proposed that chilling temperatures may lead to increases in [Ca2+]cyt in CS plant cells by reducing the rate at which they exclude Ca2+ from their cytosol and that rapid cooling (coldshock) may cause rapid increases in [Ca2+]cyt due to the activation of voltage‐dependent cation channels. Chill‐induced increases in [Ca2+]cyt in the cells of CS plants may reflect either an inherent inability of such plants to maintain homeostatic levels of Ca2+ at low temperatures or a stress‐induced reaction which has evolved to enable such cells to cope more effectively with the short‐term hardships imposed by cold. Previous proposals concerning the physiological transduction of chilling injury are also discussed. It is argued that there is little evidence to suggest that the immediate effects of low temperatures on CS cells include either decreases in ATP levels, general increases in the passive permeability of membranes, or increased rates of fermentation.

Transport Properties of the Tomato Fruit Tonoplast

“…4). There is considerable controversy about the way to fit Arrhenius plots (14 Because the low affinity Ca2+ uptake system represents a complex reaction consisting of H+ transport driven by the H+-ATPase and subsequent Ca2+/H' exchange, the effect of low temperature could be exerted at any of a number of sites in the reaction sequence. We examined the temperature dependence of individual steps in the reaction sequence by first assaying ATPase activity in the tomato and red beet membrane fractions (Fig.…”

“…However, at concentrations above 10 AM Ca2+, the N03-insensitive component of Ca2" uptake saturated and NO3-inhibition of Ca2`uptake became evident ( To further characterize the two components of ATP-dependent Ca2" uptake, inhibitor sensitivity of Ca2" uptake was determined at low (0.7 ,uM) or high (210 gM) Ca2" concentration (Table I). At high Ca2+ concentration uptake was strongly inhibited by NO3-, DCCD, and ionophores but was insensitive to as an early event in chilling injury (14,21,22) we assessed the temperature dependence of Ca2" uptake in tonoplast-enriched vesicles from both tomato and red beet. Calcium uptake in tomato membrane vesicles was linear over a time course of 20 min at both high and low temperature (Fig.…”

“…Calcium fluxes have been associated with major changes in metabolism in plants and animals (1 1,13), and it has also been proposed that transient fluctuations in cytoplasmic Ca2" activity may play a central role in chilling injury of chilling-sensitive plants (14,21,22). It is therefore of interest to obtain a complete understanding of mechanisms regulating subcellular Ca2" distribution in plant cells.…”

Chilling-Induced Lipid Degradation in Cucumber (Cucumis sativa L. cv Hybrid C) Fruit

“…Several theories have been advanced to account for the nature of CO.2 The primary lesion has been proposed to involve bulk membrane lipid phase transitions (12), unfavorable and direct low temperature effects on proteins and enzymes (7), the presence of high-melting membrane lipid species (15), and a redistribution of cellular calcium (13). Although data are available to support each of these theories, none appears to be universally accepted as the primary determinant of CI.…”

An electron microscopic-cytochemical localization of plasma membrane Ca2+-ATPase activity in poplar apical bud cells during the induction of dormancy by short-day photoperiods

“…A prolonged high level of Ca 2+ in the cytosol is harmful, and often results in metabolic dysfunction and structural damage, when such as chilling-sensitive plants are subjected to chilling stress [6], [7]. Plasma membrane (PM) Ca 2+ -ATPase plays a crucial role in controlling cytosolic Ca 2+ concentration [8][9][10][11][12][13][14].…”