Regulation of root respiration in two species of Plantago that differ in relative growth rate: the effect of short- and long-term changes in temperature.

Autor: Covey-Crump, E. M., Attwood, R. G., Atkin, O. K.
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Zdroj: Plant, Cell & Environment; Nov2002, Vol. 25 Issue 11, p1501-1513, 0p
Abstrakt: Abstract This study investigates the effect of short- and long-term changesin temperature on the regulation of root respiratory O2 uptakeby substrate supply, adenylate restriction and/or the capacityof the respiratory system. The species investigated were the lowland Plantagolanceolata L. and alpine Plantago euryphylla Briggs, Carolin& Pulley, which are inherently fast- and slow-growing, respectively. Theplants were grown hydroponically in a controlled environment (constant23 °C). The effect of long-term exposure to lowtemperature on regulation of respiration was also assessed in P.lanceolata using plants transferred to 15/10 °C(day/night) for 7 d. Exogenous glucose and uncoupler (CCCP)were used to assess the extent to which respiration rates were limitedby substrate supply and adenylates. The results suggest that adenylatesand/or substrate supply exert the greatest control overrespiration at moderate temperatures (e.g. 15–30 °C)in both species. At low temperatures (5–15 °C),CCCP and glucose had little effect on respiration, suggesting thatrespiration was limited by enzyme capacity alone. The Q 10 (proportionalincrease of respiration per 10 °C) of respirationwas increased following the addition of CCCP and/or exogenousglucose. The degree of stimulation by CCCP was considerably lowerin P. euryphylla than P. lanceolata . This suggeststhat respiration rates operate much closer to the maximum capacity in P.euryphylla than P. lanceolata . When P. lanceolata wastransferred to 15 °C for 7 d, respirationacclimated to the lower growth temperature (as demonstrated by an increasein respiration rates measured at 25 °C). In addition,the Q 10 was higher, and the stimulatory effectof exogenous glucose and CCCP lower, in the cold-acclimated rootsin comparison with their warm-grown counterparts. Acclimation of P.lanceolata to different day/night-time temperatureregimes was also investigated. The... [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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