scholarly journals Source–sink imbalance increases with growth temperature in the spring geophyte Erythronium americanum

2011 ◽  
Vol 62 (10) ◽  
pp. 3467-3479 ◽  
Author(s):  
Anthony Gandin ◽  
Sylvain Gutjahr ◽  
Pierre Dizengremel ◽  
Line Lapointe
Keyword(s):  
Growth Temperature ◽  
Erythronium Americanum ◽  
Source Sink

The influence of plant temperature on photosynthesis and translocation rates in bean and soybean

1986 ◽  
Vol 64 (10) ◽  
pp. 2337-2342 ◽  
Author(s):  
J. Marowitch ◽  
C. Richter ◽  
J. Hoddinott
Keyword(s):  
Glycine Max ◽  
Steady State ◽  
Phaseolus Vulgaris ◽  
Growth Temperature ◽  
Source Sink ◽  
Labeling System

Phaseolus vulgaris cv. Black Valentine and Glycine max cv. Maple Arrow and cv. Evans were grown at 20 °C. They were pruned to a simple source – sink system and placed in a steady-state 14C-labeling system, where their photosynthesis and translocation rates were determined at the growth temperature. The temperature of each plant was then raised or lowered and the rates were measured again. All three varieties showed net photosynthetic optima near the growth temperature. Translocation rates increased sigmoidally from 5 to 35 °C in Phaseolus, giving a decreasing Q10 value, but exponentially from 5 to 40 °C in Glycine, giving a Q10 of about 2.0. Rates were suboptimal at the highest temperatures used. Plants grown at 30 °C and exposed to higher or lower temperatures responded in parallel to the 20 °C grown plants. When grown at 12.5 °C and exposed to higher temperatures, the plants responded in parallel to the 20 °C grown ones, but at lower temperatures translocation was higher than predicted for cv. Maple Arrow.

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
Keyword(s):  
Low Temperatures ◽  
Dark Respiration ◽  
Temperature Acclimation ◽  
Respiratory Pathway ◽  
Spring Ephemeral ◽  
Sink Activity ◽  
Leaf Dark Respiration ◽  
Erythronium Americanum ◽  
Source Sink ◽  
Source And Sink

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.

Photoperiod has a stronger impact than irradiance on the source–sink relationships in the sink-limited species Erythronium americanum

Botany ◽  
2011 ◽  
Vol 89 (11) ◽  
pp. 763-770 ◽  
Author(s):  
Anthony Gandin ◽  
Pierre Dizengremel ◽  
Line Lapointe
Keyword(s):  
Feedback Control ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Feedback Inhibition ◽  
Photochemical Efficiency ◽  
Biomass Accumulation ◽  
Growth Season ◽  
Erythronium Americanum ◽  
Source Sink ◽  
Long Photoperiod

Under sink-limited conditions, source activity is modulated to remain in balance with the use of carbohydrates by the sink, but this feedback control has been studied in only a few systems so far. Sink and source activities were investigated throughout the season. Plants were subjected to two photoperiod regimes combined with two irradiance levels to produce three different daily amounts of photons. Net photosynthetic rate and the photochemical efficiency of photosynthesis were initially higher under a long photoperiod, but decreased early in the growth season, whereas they remained fairly constant until a few days before leaf senescence under a short photoperiod. The rates of starch and biomass accumulation in the bulb were also faster under a long photoperiod at the beginning of the season but reached similar levels under both short and long photoperiods later on. Response to photoperiod cannot be explained by changes in daily amounts of photons, as none of the variables reported were affected by instantaneous or daily irradiance. It appears that the total amount of carbohydrate synthesized under a long photoperiod was in excess compared to the ability of the sink to store or use them, inducing a feedback inhibition of net photosynthetic rate to restore the source–sink balance.

Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

Sign in / Sign up

Export Citation Format

Share Document