scholarly journals Thermal acclimation of leaf respiration as a way to reduce source–sink imbalance at low temperatures in Erythronium americanum, a spring ephemeral

Botany ◽  
2018 ◽  
Vol 96 (2) ◽  
pp. 97-109
Author(s):  
Yanwen Dong ◽  
Dominique Gérant ◽  
Line Lapointe

Many spring geophytes exhibit greater growth at colder than at warmer temperatures. Previous studies have suggested that there is less disequilibrium between source and sink activity at low temperatures, which delays leaf senescence and leads to higher accumulation of biomass in the perennial organ. We hypothesized that dark respiration acclimates to temperature at both the leaf and bulb levels, mainly via the alternative respiratory pathway, as a way to reduce source–sink imbalance. Erythronium americanum Ker-Gawl. was grown under three temperature regimes: 8/6 °C, 12/8 °C, and 18/14 °C (day/night). Plant respiratory rates were measured at both growth and common temperatures to determine whether differences were due to the direct effects of temperature on respiratory rates or to acclimation. Leaf dark respiration exhibited homeostasis, which together with lower assimilation at low growth temperature, most likely reduced the quantity of C available for translocation to the bulb. No temperature acclimation was visible at the sink level. However, bulb total respiration varied through time, suggesting potential stimulation of bulb respiration as sink limitation builds up. In conclusion, acclimation of respiration at the leaf level could partly explain the better equilibrium between source and sink activity in plants grown in low-temperatures, whereas bulb respiration responds to source–sink imbalance.

1978 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
AJ Hall ◽  
FL Milthorpe

Removal of the rapidly growing fruit from a Capsicum plant reduced the rate of net CO2 uptake by its leaves by up to 30% during the time period explored (0.5 - 7 days). This reduction was associated with increases in both the leaf (to about 200%) and intracellular (to about 30%) resistances, these changes having about equal effects on reducing the rate of CO2 uptake. Changes in photorespiration, dark respiration and CO2 compensation point were very small. The rate of CO2 uptake and the associated resistances were also changed by modifying the light regime and other factors affecting the source-sink balance. Changes in the leaf resistance were not attributable to variations in the internal CO2 concentration or in the water economy of the leaf; its control mechanism remains unexplained. The concentration of soluble sugars in the source leaf was completely unaffected but that of polysaccharides was changed by defruiting and by 50% defoliation. However, variations in the intracellular resistance were not closely related to these changes and there is yet no evidence of the nature of its control mechanism. Changes in both soluble sugars and polysaccharides in the stem were more pronounced than in the leaves.


2008 ◽  
Vol 35 (6) ◽  
pp. 448 ◽  
Author(s):  
Lai Fern Ow ◽  
David Whitehead ◽  
Adrian S. Walcroft ◽  
Matthew H. Turnbull

Pinus radiata L. were grown in climate-controlled cabinets under three night/day temperature treatments, and transferred between treatments to mimic changes in growth temperature. The objective was to determine the extent to which dark respiration and photosynthesis in pre-existing and new needles acclimate to changes in growth temperatures. We also assessed whether needle nitrogen influenced the potential for photosynthetic and respiratory acclimation, and further assessed if short-term (instantaneous, measured over a few hours) respiratory responses are accurate predictors of long-term (acclimated, achieved in days–weeks) responses of respiration to changing temperature. Results show that respiration displayed considerable potential for acclimation. Cold and warm transfers resulted in some acclimation of respiration in pre-existing needles, but full acclimation was displayed only in new needles formed at the new growth temperature. Short-term respiratory responses were poor predictors of the long-term response of respiration due to acclimation. There was no evidence that photosynthesis in pre-existing or new needles acclimated to changes in growth temperature. N status of leaves had little impact on the extent of acclimation. Collectively, our results indicate that there is little likelihood that respiration would be significantly stimulated in this species as night temperatures increase over the range of 10–20°C, but that inclusion of temperature acclimation of respiration would in fact lead to a shift in the balance between photosynthesis and respiration in favour of carbon uptake.


2017 ◽  
Vol 44 (11) ◽  
pp. 1075 ◽  
Author(s):  
Michael J. Aspinwall ◽  
Vinod K. Jacob ◽  
Chris J. Blackman ◽  
Renee A. Smith ◽  
Mark G. Tjoelker ◽  
...  

The effects of elevated CO2 on the short-term temperature response of leaf dark respiration (R) remain uncertain for many forest tree species. Likewise, variation in leaf R among populations within tree species and potential interactive effects of elevated CO2 are poorly understood. We addressed these uncertainties by measuring the short-term temperature response of leaf R in 15 provenances of Eucalyptus grandis W. Hill ex Maiden from contrasting thermal environments grown under ambient [CO2] (aCO2; 400 µmol mol–1) and elevated [CO2] (640 µmol mol–1; eCO2). Leaf R per unit area (Rarea) measured across a range of temperatures was higher in trees grown in eCO2 and varied up to 104% among provenances. However, eCO2 increased leaf dry mass per unit area (LMA) by 21%, and when R was expressed on a mass basis (i.e. Rmass), it did not differ between CO2 treatments. Likewise, accounting for differences in LMA among provenances, Rmass did not differ among provenances. The temperature sensitivity of R (i.e. Q10) did not differ between CO2 treatments or among provenances. We conclude that eCO2 had no direct effect on the temperature response of R in E. grandis, and respiratory physiology was similar among provenances of E. grandis regardless of home-climate temperature conditions.


2013 ◽  
Vol 40 (11) ◽  
pp. 1159 ◽  
Author(s):  
Yonggang Chi ◽  
Ming Xu ◽  
Ruichang Shen ◽  
Shiqiang Wan

A better understanding of thermal acclimation of leaf dark respiration in response to nocturnal and diurnal warming could help accurately predict the changes in carbon exchange of terrestrial ecosystems under global warming, especially under the asymmetric warming. A field manipulative experiment was established with control, nocturnal warming (1800–0600 hours), diurnal warming (0600–1800 hours), and diel warming (24 h) under naturally fluctuating conditions in a semiarid temperate steppe in northern China in April 2006. Temperature response curves of in situ leaf dark respiration for Stipa krylovii Roshev. were measured at night (Rn) and after 30 min of darkness imposed in the daytime (Rd). Leaf nonstructural carbohydrates were determined before sunrise and at sunset. Results showed that Rn could acclimate to nocturnal warming and diurnal warming, but Rd could not. The decreases in Q10 (temperature sensitivity) of Rn under nocturnal-warming and diurnal warming regimes might be attributed to greater depletion of total nonstructural carbohydrates (TNC). The real-time and intertwined metabolic interactions between chloroplastic and mitochondrial metabolism in the daytime could affect the impacts of warming on metabolite pools and the distinct response of Rn and Rd to warming. Projection on climate change–carbon feedback under climate warming must account for thermal acclimation of leaf dark respiration separately by Rn and Rd.


2002 ◽  
Vol 29 (12) ◽  
pp. 1465 ◽  
Author(s):  
Edwin Kraus ◽  
Margje Voeten ◽  
Hans Lambers

Autotoxicity and allelopathy affect the respiration and yield of GL66 and GL72, two populations of perennial ryegrass (Lolium perenne L. cv. S23) that were originally selected for contrasting rates of mature-leaf dark respiration under conditions where allelopathic effects could not occur and autotoxic effects were minimal. The aim of this study was to further investigate growth and biomass allocation of these two populations in relation to their autotoxic and allelopathic properties. To this end, plants were subjected to two conditions (monoculture and mixed culture) and two treatments (growth in 'renewed' and 'replenished' nutrient solution, allowing for short- and long-term accumulation of allelochemicals, respectively). The fast-respiring population, GL66, showed a reduced total yield due to allelopathic effects only when long-term accumulation of allelochemicals was allowed (mixed culture, replenished). However, short-term accumulation (mixed culture, renewed) of allelochemicals was sufficient to affect allocation of biomass to leaf sheaths. The slow-respiring population, GL72, suffered from autotoxicity only when long-term accumulation was allowed (monoculture, replenished), and from allelopathy under both short- and long-term accumulation (mixed culture, either renewed or replenished). The predominant allelopathic and autotoxic effect was on dry matter percentage and dry weight of leaf sheaths. We conclude that the roots of both populations release one or more chemical compounds that primarily affect biomass allocation to leaf sheaths, both of the same and of the other population. Sensitivity to the putative inhibitor(s) released by the other population was greater than sensitivity to the inhibitor(s) released by a population's own roots.


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