Physiological responses of banana (MusaAAA; Cavendish sub-group) in the subtropics. II. Influence of climatic conditions on seasonal and diurnal variations in gas exchange of banana leaves

1995 ◽  
Vol 70 (1) ◽  
pp. 157-167 ◽  
Author(s):  
K. Eckstein ◽  
J. C. Robinson
2011 ◽  
Vol 116 (D15) ◽  
Author(s):  
L. K. Sahu ◽  
Y. Kondo ◽  
Y. Miyazaki ◽  
Prapat Pongkiatkul ◽  
N. T. Kim Oanh

2019 ◽  
Author(s):  
Johannes Brändle ◽  
Norbert Kunert

Abstract Tree autotrophic respiratory processes, especially stem respiration or stem CO2 efflux (Estem), are important components of the forest carbon budget. Despite the efforts to investigate the controlling processes of Estem in the last years a considerable lack in our knowledge remains on the abiotic and biotic drivers affecting Estem dynamics. It has been strongly advocated that long-term measurements would shed light into those processes. The expensive scientific instruments needed to measure gas exchange has prevented from applying Estem measurements on a larger temporal and spatial scale. Here, we present an automated closed dynamic chamber system based on inexpensive and industrially broadly applied CO2 sensors reducing the costs for the sensing system to a minimum. The CO2 sensor was cross-calibrated with a commonly used gas exchange system in the laboratory and in the field, and we found very good accordance of these sensors. We tested the system under harsh tropical climatic conditions, characterized by heavy tropical rainfall events, extreme humidity, and temperatures, in a moist lowland forest in Malaysia. We recorded Estem of three Dyera costulata trees with our prototype over various days. The variation of Estem was large among the three tree individuals and varied by 7.5-fold. However, clear diurnal changes in Estem were present in all three tree individuals. One tree showed high diurnal variation in Estem and the relationship between Estem and temperature was characterized by a strong hysteresis. The large variations found within one single tree species highlights the importance of continuous measurement to quantify ecosystem carbon fluxes.


2015 ◽  
Vol 120 (2) ◽  
pp. 311-342 ◽  
Author(s):  
S. W. Bougher ◽  
D. Pawlowski ◽  
J. M. Bell ◽  
S. Nelli ◽  
T. McDunn ◽  
...  

2009 ◽  
Vol 13 (7) ◽  
pp. 987-998 ◽  
Author(s):  
Z. Gao ◽  
D. H. Lenschow ◽  
Z. He ◽  
M. Zhou

Abstract. In order to examine energy partitioning and CO2 exchange over a steppe prairie in Inner Mongolia, China, fluxes of moisture, heat and CO2 in the surface layer from June 2007 through June 2008 were calculated using the eddy covariance method. The study site was homogenous and approximately 1500 m×1500 m in size. Seasonal and diurnal variations in radiation components, energy components and CO2 fluxes are examined. Results show that all four radiation components changed seasonally, resulting in a seasonal variation in net radiation. The radiation components also changed diurnally. Winter surface albedo was higher than summer surface albedo because during winter the snow-covered surface increased the surface albedo. The seasonal variations in both sensible heat and CO2 fluxes were stronger than those of latent heat and soil heat fluxes. Sensible heat flux was the main consumer of available energy for the entire experimental period. The energy imbalance problem was encountered and the causes are analyzed.


2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Murthazar Naim Raai ◽  
Nurul Amalina Mohd Zain ◽  
Normaniza Osman ◽  
Nur Ardiyana Rejab ◽  
Nurul Amylia Sahruzaini ◽  
...  

ABSTRACT: An experiment was conducted to investigate the effects of different shading regimes [i.e., 60% (heavy), 30% (moderate), and 0% (control)] on 25 traits associated with the morphological features, photosynthetic gas exchange and agronomic characteristics of winged bean (Psophocarpus tetragonolobus), an underutilized protein-rich legume from the tropics. Collectively, 80% of the studied variables displayed significant differences (P<0.05) between at least two shade treatments. Shading generally showed most pronounced effect on the physiological traits of the legume, whereby the stomatal conductance, photosynthetic and transpiration rate differed significantly among plants for all treatments. The non-shaded plants were observed to have superior growth and physiological responses than the shaded plants. Interestingly, the moderately shaded plants exhibited the highest yield per plant, which significantly differed from the non-shaded and heavily shaded plants. This indicated that winged bean can adapt to partial canopy cover, making it a potential nitrogen-fixing cash crop which can be planted together with fruit or oil trees in commercial plantations.


2019 ◽  
Vol 96 (8) ◽  
pp. 766-769 ◽  
Author(s):  
Inessa V. Averyanova ◽  
S. I. Vdovenko ◽  
A. L. Maksimov

Natural and climatic conditions of the environment of Northeast Russia and particularly Magadan region are the very factor mostly influencing adaptive responses by individuals inhabiting the region. Compensatory and adaptive responses in indigenes and newcomers of the region can be assumed to have their specific features. In 2009 there was executed the examination of the cardiovascular and respiratory systems and gas exchange in 392 cases aged of 17-19 years, including Europeans (Caucasians) born in the North in the 1st-2nd generation and indigenes. The methodologically similar study was carried out in 2014 in 265 persons, referred to the same cohorts of North-born Caucasians and Indigenes from the Magadan region. The results of the study executed in 2009 testified to a small number of physiological parameters that were reliably different in Caucasians vs. Indigene subjects. In 2014 no difference was found between the two examined cohorts throughout the observed parameters. The revealed changes in gas exchange, external respiration and cardiovascular systems demonstrated by modern young Indigenes of Northeast Russia testified to the fall in the effectiveness of their breathing. All that makes them farther from the classic “polar metabolic type” and their morphofunctional status becomes closer to European male subjects of Northeast Russia. Thus, we can observe a clear tendency towards “convergence in programs” of the adaptive changes between populations of the North residents undergoing similar natural, environmental and social factors.


Sign in / Sign up

Export Citation Format

Share Document