Intercellular CO2 concentration and water-use efficiency of temperate plants with different life-forms and from different microhabitats

Oecologia ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 370-374 ◽  
Author(s):  
F. Yoshie
2019 ◽  
Vol 14 (2) ◽  
pp. 138 ◽  
Author(s):  
Viviane Maria Ruela ◽  
Adriano Bortolotti da Silva ◽  
André Delly Veiga ◽  
Thiago Corrêa de Souza ◽  
Daniele Maria Marques ◽  
...  

Research has shown that, in addition to the fungicidal action already known, strobilurins have positive physiological effects on the yield of some crops. Boscalid has also shown positive effects on plants, applied together or associated with strobilurin. The objective in this study was to evaluate the effect of fungicide application on growth and physiological behavior of coffee seedlings. The experimental design was in randomized blocks, with five replicates. There were five treatments: T1-Control, T2-Boscalid, T3-Pyraclostrobin, T4- Boscalid+ Pyraclostrobin and T5- Azoxystrobin applied in coffee seedlings. The application was at the “orelha de onça” stage (two round-shaped leaves), repeated every 15 days, counting 5 applications in total. Were evaluated shoot length, root length, stem diameter, shoot and root fresh matter, shoot and root dry matter, leaf photosynthesis, stomatal conductance, transpiration, intercellular CO2 concentration, water use efficiency and carboxylation efficiency. The application of fungicides promotes greater vegetative growth of coffee seedlings due to increased CO2 assimilation rate, reduced transpiration rates and increased water use efficiency, associated to the increased levels of auxin and cytokinins in leaves


Author(s):  
Márcio De Souza Dias ◽  
Douglas José Marques ◽  
Hudson Carvalho Bianchini

Aims: The objective of this research was to investigate the effect of calcium silicate on gaseous exchanges and production factors in the sweet pepper, cultivated under conditions of soil salinity induced by potassium fertilization, in protected cultivation. Study Design: The experiment was arranged in a randomized complete block design in a 2 × 5 factorial scheme with five replications. Place and Duration of Study: The experiment was conducted in the sector of Olericultura and Experimentation of the course of Agronomy from October 12, 2018 to February 2019. Methodology: The experiment was arranged in a randomized complete block design in a 2 × 5 factorial scheme (two sources of correction: calcareous and silicon and five increasing rates of KCl equivalent to 150, 300, 450, 600 and 700 kg ha-1 of K2O). Ten treatments with five replicates where each experimental unit consisted of a polyethylene pot, with a volume of 19 dm3. The electrical conductivity, the determination and quantification of silicon in soil and plant, liquid photosynthesis, stomatal conductance, intercellular CO2 concentration, transpiration, water use efficiency and instantaneous carboxylation efficiency were analyzed. Results: With the increase of K2O in the soil there was a tendency of reduction in liquid photosynthesis, transpiration, stomatal conductance, intercellular CO2 concentration, water use efficiency and instantaneous carboxylation efficiency in the presence and absence of calcium silicate. Higher rates of K2O (300, 450 and 600 kg ha-1) reduced the length and yield of sweet pepper fruits in the presence and absence of calcium silicate. The rate of 150 Kg K2O favored the growth of sweet pepper plants in the presence of calcium silicate. Conclusion: It is concluded from the research that the dose of 300 kg ha-1 of K2O, in the presence of calcium silicate, provided the best results for the electrical conductivity of 2.76 dS m-1, silicon content in the soil of 5.70 mg kg-1, 14% silicon leaf content, improving photosynthetic rates, transpiration, water use efficiency and fruit production. The increase in salinity reduced fruit yield, in the presence and absence of Si.


2014 ◽  
Vol 41 (3) ◽  
pp. 244 ◽  
Author(s):  
Ana-Maria Hereş ◽  
Jordi Voltas ◽  
Bernat Claramunt López ◽  
Jordi Martínez-Vilalta

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.


Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 465
Author(s):  
Wenming Wu ◽  
Shiji Wang ◽  
Lin Zhang ◽  
Jincai Li ◽  
Youhong Song ◽  
...  

In the southern Huang-Huai-Hai (HHH) region, China, maize production is frequently threatened by waterlogging at the seedling stage and by drought at the big flare stage. A two-year field experiment was performed to explore whether subsoiling (SS) in the winter wheat season could improve the photosynthetic capacity and increase the water use efficiency (WUE) of summer maize using the variety, Luyu9105. A split design was adopted in the experiment. The main plots used tillage practices, including SS and rotary tillage (RT). The subplots consisted of two irrigation methods, i.e., applied supplemental irrigation at the big flare stage (I) and no irrigation at the big flare stage (NI). The results showed that the SS treatment significantly increased soil water content (SWC) in the 40–60 cm soil layer. The SS treatment improved green leaf area index (gLAI) by 15.1%–30.2%, and enhanced the ear-leaf net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (ci) and transpiration rate (Tr), and was accompanied by an increase in the grain-filling duration (T) by 5 days and the mean grain-filling rate (Va). The SS treatment decreased the stomatal limitation (Ls), indicating that RT treatment, which was under lower SWC, led to a decrease in Pn. Applied supplemental irrigation under RT treatment was able to compensate for the growth of leaves, but could not reverse the decreasing trend in the gLAI. Ultimately, the SS treatment improved WUE by 9.1%–9.9%, and increased grain yields by 10.0%–29.3%. Therefore, this study showed that in the southern Huang-Huai-Hai Plain, which has a yellow cinnamon soil type, the practice of SS can improve the photosynthetic characteristics of leaves and WUE of rainfed summer maize.


Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 642 ◽  
Author(s):  
Guobao Xu ◽  
Xiaohong Liu ◽  
Soumaya Belmecheri ◽  
Tuo Chen ◽  
Guoju Wu ◽  
...  

Intrinsic water-use efficiency (iWUE) is affected by the balance of photosynthetic rate, stomatal conductance, and climate, along with many other exogenous factors, such as the CO2 concentration in the atmosphere (CO2atm), nutrients, and water holding capacity of the soil. The relative contributions of CO2atm and climate to iWUE are still incompletely understood, particularly for boreal forests where the climate is undergoing unprecedented warming. We combined δ13C and δ18O in tree rings from the Siberian larch (Larix sibirica Ledeb.) in Northwestern China’s Altay Mountains, which receives 190 mm in annual precipitation, to detect the drivers of long-term iWUE changes and their time-varying contributions over the past 222 years. A climate optimization approach was used to isolate the influence of climate from CO2atm influence on iWUE. We found that iWUE increased about 33.6% from 1790 to 2011, and rising CO2atm contributed 48.8% to this iWUE increase. The contributions of CO2atm and climate (drought conditions) varied during the study period 1790–2011. From 1790 to 1876, the climate was the most important factor contributing to the changes in iWUE. From 1877 to 1972, CO2atm was the main contributor; however, after 1973, the climate was again the dominant contributor to the increase in iWUE, especially during 1996–2011. During the period 1996–2011, climate substantially (83%) contributed to the iWUE increase. Our findings imply that, in the boreal forest in Northwestern China’s arid region, iWUE experienced three changes: (1) the climate dominating from 1790 to 1876; (2) CO2atm dominating from 1877 to 1972, and (3) climate dominating again during the past four decades. We observed that the relationships between iWUE and tree-ring width shifted from positive to negative from 1996 onwards. These relationship changes indicate that CO2atm-mediated effects of increasing iWUE on tree growth are counteracted by climatic drought stress and iWUE increase cannot counter the stress from drought on tree growth in China’s arid boreal forest.


2019 ◽  
Vol 43 (4) ◽  
Author(s):  
Keila Rêgo Mendes ◽  
Marcos Bento ◽  
Ricardo Antonio Marenco

ABSTRACT The response of leaf traits to irradiance and [CO2] in canopy leaves of several tall trees remains to be determined under natural conditions. Thus, the objective of this work was to determine gas-exchange parameters in sun and shade leaves of Dinizia excelsa Ducke in 35-45 m tall trees of Central Amazonia. We assessed light saturated photosynthesis (Amax), stomatal conductance (gs), mesophyll conductance (gm), transpiration rates (E), water use efficiency (WUE), intrinsic water use efficiency (WUEi), maximum electron transport rate (Jmax), the maximum carboxylation rate of Rubisco (Vcmax), intercellular CO2 concentration (Ci)specific leaf area (SLA) and fresh leaf thickness. We also estimated the CO2 concentration at the chloroplast level (Cc) and determined the light and CO2 saturated photosynthesis (Apot). Amax was obtained at light saturation (1200 µmol m-2 s-1), whereas Apot, Vcmax, Jmax and gm were obtained after constructing A/Ci response curves. There was a significant difference between sun and shade leaves in Ci and Cc, but for other parameters no differences were observed. Amax was positively correlated with gs, gm and E, and there was also a significant correlation between gs and gm (p ≤ 0.05), as well as between Jmax and Vcmax. Thicker leaves had higher values of Amax, gs, Ci, Cc and E. Apot was limited by the electron transport rate and by low gm. The canopy of the tree caused a decrease in irradiance (30-40%), but this reduction was not enough to reduce important photosynthetic parameters. Thus, all resources allocated to leaf production led to maximum use of the solar energy received by the leaves, which allowed this species to grow at fairly rapid rates.


2016 ◽  
Author(s):  
Na Zhao ◽  
Ping Meng ◽  
Yabing He ◽  
Xinxiao Yu

Abstract. In the context of global warming attributable to the increasing levels of CO2, severe drought can be anticipated in areas with chronic water shortages (semi-arid areas), which necessitates research on the interaction between elevated atmospheric concentrations of CO2 and drought on plant photosynthetic discrimination. As δ13C of water-soluble compounds in leaves was depleted from extracellular CO2 to primary assimilates, no explanation has been offered for 13C fractionation before leaf-exported transportation of photosynthate. Either its variation according to the CO2 concentration and/or water stress gradients, or their interaction have not yet been identified. Therefore, saplings of species typical to a semi-arid area of Northern China that have similar growth status – Platycladus orientalis and Quercus variabilis – were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentrations [CO2] × five soil volumetric water contents (SWC)). The δ13C of water-soluble compounds extracted from leaves of potted saplings was measured to determine the instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas exchange (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-exported translocation of primary assimilates. The WUEge of the two saplings both decreased with increased soil moisture, and increased with elevated [CO2] at 35 %–80 % of Field Capacity (FC) by strengthening photosynthetic capacity and reducing transpiration. Differences in instantaneous water use efficiency (iWUE) according to distinct environmental changes differed between the species. The WUEge of P. orientalis was significantly greater than that of Q. variabilis, while the opposite results were obtained in a comparison of the WUEcp of the two species. The differences between WUEge and WUEcp were clearly species-specific, as demonstrated in the interaction of [CO2] and SWC. Rising [CO2] coupled with moistened soil generated increasing disparities between WUEge and WUEcp in P. orientalis with an amplitude of 0.0328 ‰–0.0472 ‰. Further, the differences between WUEge and WUEcp of Q. variabilis increased as CO2 concentration increased and water stress alleviated (0.0384 ‰–0.0466 ‰). The 13C fractionation in post-photosynthesis was linearly dependent on gs, and was attributed to environmental variation. Thus, cautious descriptions of the magnitude and environmental dependence of apparent post-carboxylation fractionation are worth our attention in photosynthetic fractionation.


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