Influence of temperature and soil drying on respiration of individual roots in citrus: integrating greenhouse observations into a predictive model for the field

Abstract

In citrus, the majority of fine roots are distributed near the soil surface -a region where conditions are frequently dry and temperatures fluctuate considerably. To develop a better understanding of the relationship between changes in soil conditions and a plant's below-ground respiratory costs, the effects of temperature and soil drying on citrus root respiration were quantified in controlled greenhouse experiments. Chambers designed for measuring the respiration of individual roots were used. Under moist soil conditions, root respiration in citrus increased exponentially with changes in soil temperature ( Q 10 = 1·8-2·0), provided that the changes in temperature were short-term. However, when temperatures were held constant, root respiration did not increase exponentially with increasing temperatures. Instead, the roots acclimated to controlled temperatures above 23 ∞ ∞ ∞ ∞ C, thereby reducing their metabolism in warmer soils. Under drying soil conditions, root respiration decreased gradually beginning at 6% soil water content and reached a minimum at <2% soil water content in sandy soil. A model was constructed from greenhouse data to predict diurnal patterns of fine root respiration based on temperature and soil water content. The model was then validated in the field using data obtained by CO 2 trapping on root systems of mature citrus trees. The trees were grown at a site where the soil temperature and water content were manipulated. Respiration predicted by the model was in general agreement with observed rates, which indicates the model may be used to estimate entire root system respiration for citrus.

Impacts of Heat Stress on Wheat: A Critical Review

“…The rate of respiration exponentially increases with elevated temperatures from 0 to 35°C or 40°C, reaching plateau at 40°C to 50°C however, at temperatures above 50°C, the rate of respiration decreases as a consequence of destruction of respiratory mechanism. Short term exposure of drought stress can result in decrease in leaf and root respiration [78]. Mitochondria show greater stability to heat stress and their activity increases over most of the temperature range in which plants are grown.…”

Gas Exchange Analysis for Estimating Net CO2Fixation Capacity of Mangrove (Rhizophora stylosa) Forest in the Mouth of River Fukido, Ishigaki Island, Japan

“…In this respect, it is also necessary to improve the accurancy of the estimation of photosynthetic CO 2 absorption. The second is to treat the samples of each organ for the measurement of RCER with NaClO (Nobel and Palta, 1989;McKee, 1996;Bryla et al, 2001). This procedure was done to omit excess CO 2 emission from bacteria attached on the surface of the tissues (Alongi, 1989;Clough, 1992).…”

Effects of rhizobacteria on the respiration and growth of Cerasus sachalinensis Kom. seedlings

“…This proved that bacterial strains of the same genus might have opposite effects. Respiratory metabolism is the core of belowground growth and root development and provides raw materials and energy for plant physiological activity, which is sensitive to alterations in the rhizosphere environment (Bryla et al, 2001). In vitro tests and cellular analysis of root tips revealed inhibition of primary root growth caused by synergistic effects on bacterial consortia (Felici et al, 2008).…”