scholarly journals How Do Different Cocoa Genotypes Deal with Increased Radiation? An Analysis of Water Relation, Diffusive and Biochemical Components at the Leaf Level

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1422
Author(s):  
Juan Carlos Suárez ◽  
Cristian Gelpud ◽  
Jhon Eduar Noriega ◽  
Fausto Andrés Ortiz-Morea
Keyword(s):  
Water Status ◽  
Carbon Assimilation ◽  
Water Relation ◽  
Antioxidant Systems ◽  
Radiation Level ◽  
Carbon Assimilation Rate ◽  
Protection Mechanisms ◽  
Leaf Level ◽  
Use Efficiency

The cultivation of cocoa (Theobroma cacao L.) is traditionally managed under shade because of its photosynthetic characteristics; however, its behavior can vary according to the genotype and environmental conditions where it is grown. In this sense, here, we explore the possible mechanisms of protection against radiation stress and how these mechanisms are affected by variation between cocoa genotypes. Therefore, we evaluate the effect of the radiation level (HPAR, 2100 ± 46 mol m−2 s−1; MPAR, 1150 ± 42 mol m−2 s−1; LPAR, 636 ± 40 mol m−2 s−1) on the water status and gas exchange in plants of different cocoa genotypes (CCN-51, ICS-1, ICS-95, LUKER-40 and LUKER-50), and the occurrence of photoinhibition of PSII (as a marker of photodamage), followed by a characterization of the protection mechanisms, including the dynamics of photosynthetic pigments and enzymatic and non-enzymatic antioxidant systems. We found significant changes in the specific leaf area (SLA) and the water potential of the leaf (ΨL) due to the level of radiation, affecting the maximum quantum yield of PSII (Fv/Fm), which generated dynamic photoinhibition processes (PIDyn). Cocoa genotypes showed the lowest Light-saturated maximum net carbon assimilation rate (Amax) in HPAR. Moreover, the maximum carboxylation rate (Vcmax) was negatively affected in HPAR for most cocoa genotypes, indicating less RuBisCO activity except for the ICS-95 genotype. The ICS-95 showed the highest values of Vcmax and maximum rate of regeneration of ribulose-1,5-bisphosphate (RuBP) controlled by electron transport (Jmax) under HPAR. Hence, our results show that some genotypes were acclimated to full sun conditions, which translated into greater carbon use efficiency due to the maximization of photosynthetic rates accompanied by energy dissipation mechanisms.

Partial rootzone drying improves almond tree leaf-level water use efficiency and afternoon water status compared with regulated deficit irrigation

2011 ◽  
Vol 38 (5) ◽  
pp. 372 ◽  
Author(s):  
Gregorio Egea ◽  
Ian C. Dodd ◽  
María M. González-Real ◽  
Rafael Domingo ◽  
Alain Baille
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Stem Water Potential ◽  
Regulated Deficit Irrigation ◽  
Leaf Level ◽  
Use Efficiency ◽  
Stem Water ◽  
Partial Rootzone Drying

To determine whether partial rootzone drying (PRD) optimised leaf gas exchange and soil–plant water relations in almond (Prunus dulcis (Mill.) D.A. Webb) compared with regulated deficit irrigation (RDI), a 2 year trial was conducted on field-grown trees in a semiarid climate. Five irrigation treatments were established: full irrigation (FI) where the trees were irrigated at 100% of the standard crop evapotranspiration (ETc); three PRD treatments (PRD70, PRD50 and PRD30) that applied 70, 50 and 30% ETc, respectively; and a commercially practiced RDI treatment that applied 50% ETc during the kernel-filling stage and 100% ETc during the remainder of the growth season. Measurements of volumetric soil moisture content in the soil profile (0–100 cm), predawn leaf water potential (Ψpd), midday stem water potential (Ψms), midday leaf gas exchange and trunk diameter fluctuations (TDF) were made during two growing seasons. The diurnal patterns of leaf gas exchange and stem water potential (Ψs) were appraised during the kernel-filling stage in all irrigation regimes. When tree water relations were assessed at solar noon, PRD did not show differences in either leaf gas exchange or tree water status compared with RDI. At similar average soil moisture status (adjudged by similar Ψpd), PRD50 trees had higher water status than RDI trees in the afternoon, as confirmed by Ψs and TDF. Although irrigation placement showed no effects on diurnal stomatal regulation, diurnal leaf net photosynthesis (Al) was substantially less limited in PRD50 than in RDI trees, indicating that PRD improved leaf-level water use efficiency.

Responses of Mungbean to Water Deficit, Water use Efficiency and Drought Resistance

2021 ◽  
Author(s):  
B. Sajitha ◽  
R. Karthiyayini ◽  
Samundeeswari .
Keyword(s):  
Drought Stress ◽  
Mung Bean ◽  
Water Status ◽  
Nitrate Assimilation ◽  
Water Relation ◽  
Cellular Level ◽  
Protective Mechanism ◽  
Agricultural Crop ◽  
Use Efficiency ◽  
The Impact

Backround: Legumes are the second important agricultural crop of great prominence to humans. Among 20000 legume species the mungbean is one of the most important grain cultivated in India. Drought is a major environmental stress that affects mungbean in the sub-humid, dry and intermediate zones of India. The present study records the response of mung bean varieties to water stress during its growth stage.Methods: The impact of drought stress imposed on the crop was evaluated by measuring the water relation parameters and the biochemical progresses like osmolyte accumulation, nitrate assimilation and antioxidant system in Mung bean during 2017-2018 in Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore.Result: Drought stress altered the water status of the crop by reducing the RWC, which was enhanced in drought susceptible varieties. Increased amount of proline denotes the osmoregulatory mechanism in the crop to bring about resistance and the elevated levels of antioxidant enzymes shows the protective mechanism in the crop at cellular level.

scholarly journals Characterization of Carbon Assimilation Rate, Stomatal Conductance and Transpiration Rate for Eight Proteaceae Species.

2000 ◽  
Vol 69 (5) ◽  
pp. 576-583 ◽  
Author(s):  
Genaro A. Reynoso ◽  
Masahiro Morokuma ◽  
Yoshie Miura ◽  
Atsushi Hasegawa ◽  
Masanori Goi
Keyword(s):  
Stomatal Conductance ◽  
Transpiration Rate ◽  
Carbon Assimilation ◽  
Assimilation Rate ◽  
Carbon Assimilation Rate

scholarly journals Salt acclimation induced salt tolerance is enhanced by abscisic acid priming in wheat

2017 ◽  
Vol 63 (No. 7) ◽  
pp. 307-314 ◽  
Author(s):  
Wang Zongshuai ◽  
Li Xiangnan ◽  
Zhu Xiancan ◽  
Liu Shengqun ◽  
Song Fengbin ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Salt Stress ◽  
Salt Tolerance ◽  
Water Status ◽  
Carbon Assimilation ◽  
Photosynthetic Electron Transport ◽  
Triticum Aestivum L ◽  
Antioxidant Systems ◽  
Salt Acclimation ◽  
High Salt Stress

High salt stress significantly depresses carbon assimilation and plant growth in wheat (Triticum aestivum L.). Salt acclimation can enhance the tolerance of wheat plants to salt stress. Priming with abscisic acid (1 mmol ABA) was applied during the salt acclimation (30 mmol NaCl) process to investigate its effects on the tolerance of wheat to subsequent salt stress (500 mmol NaCl). The results showed that priming with ABA modulated the leaf ABA concentration to maintain better water status in salt acclimated wheat plants. Also, the ABA priming drove the antioxidant systems to protect photosynthetic electron transport in salt acclimated plants against subsequent salt stress, hence improving the carbon assimilation in wheat. It suggested that salt acclimation induced salt tolerance could be improved by abscisic acid priming in wheat.

scholarly journals Alien introgression and morpho-agronomic characterization of diploid progenies of Solanum lycopersicoides monosomic alien addition lines (MAALs) toward pre-breeding applications in tomato (S. lycopersicum)

2021 ◽  
Author(s):  
Puneet Kaur Mangat ◽  
Junghyun Shim ◽  
Ritchel B. Gannaban ◽  
Joshua J. Singleton ◽  
Rosalyn B. Angeles-Shim
Keyword(s):  
Chromosome Complement ◽  
Introgression Lines ◽  
Addition Lines ◽  
Solanum Lycopersicoides ◽  
Drought Tolerant ◽  
Use Efficiency ◽  
Tomato Breeding ◽  
Chromosome Segments ◽  
Alien Addition Lines

Abstract Key message Alien introgressions that were captured in the genome of diploid plants segregating from progenies of monosomic alien addition lines of S. lycopersicoides confer novel phenotypes with commercial and agronomic value in tomato breeding. Abstract Solanum lycopersicoides is a wild relative of tomato with a natural adaptation to a wide array of biotic and abiotic challenges. In this study, we identified and characterized diploid plants segregating from the progenies of monosomic alien addition lines (MAALs) of S. lycopersicoides to establish their potential as donors in breeding for target trait improvement in tomato. Molecular genotyping identified 28 of 38 MAAL progenies having the complete chromosome complement of the cultivated tomato parent and limited chromosome introgressions from the wild S. lycopersicoides parent. Analysis of SSR and indel marker profiles identified 34 unique alien introgressions in the 28 MAAL-derived introgression lines (MDILs) in the genetic background of tomato. Conserved patterns of alien introgressions were detected among sibs of MDILs 2, 3, 4 and 8. Across MDILs, a degree of preferential transmission of specific chromosome segments was also observed. Morphologically, the MDILs closely resembled the cultivated tomato more than S. lycopersicoides. The appearance of novel phenotypes in the MDILs that are lacking in the cultivated parent or the source MAALs indicates the capture of novel genetic variation by the diploid introgression lines that can add commercial and agronomic value to tomato. In particular, screening of representative MDILs for drought tolerance at the vegetative stage identified MDIL 2 and MDIL 11III as drought tolerant based on visual scoring. A regulated increase in stomatal conductance of MDIL 2 under drought stress indicates better water use efficiency that allowed it to survive for 7 days under 0% moisture level.

Altitude of origin influences stomatal conductance and therefore maximum assimilation rate in Southern Beech, Nothofagus cunninghamii

2000 ◽  
Vol 27 (5) ◽  
pp. 451 ◽  
Author(s):  
Mark J. Hovenden ◽  
Tim Brodribb
Keyword(s):  
Stomatal Conductance ◽  
Stomatal Density ◽  
Carbon Assimilation ◽  
Co2 Concentration ◽  
Carboxylation Efficiency ◽  
Assimilation Rate ◽  
Carbon Assimilation Rate ◽  
Southern Beech ◽  
Maximum Stomatal Conductance ◽  
Leaf Biochemistry

Gas exchange measurements were made on saplings of Southern Beech, Nothofagus cunninghamii (Hook.) Oerst. collected from three altitudes (350, 780 and 1100 m above sea level) and grown in a common glasshouse trial. Plants were grown from cuttings taken 2 years earlier from a number of plants at each altitude in Mt Field National Park, Tasmania. Stomatal density increased with increasing altitude of origin, and stomatal con-ductance and carbon assimilation rate were linearly related across all samples. The altitude of origin influenced thestomatal conductance and therefore carbon assimilation rate, with plants from 780 m having a greater photosynthetic rate than those from 350 m. The intercellular concentration of CO2 as a ratio of external CO2 concentration (ci/ca) was similar in all plants despite the large variation in maximum stomatal conductance. Carboxylation efficiency was greater in plants from 780 m than in plants from 350 m. Altitude of origin has a strong influence on the photo-synthetic performance of N. cunninghamii plants even when grown under controlled conditions, and this influence is expressed in both leaf biochemistry (carboxylation efficiency) and leaf morphology (stomatal density).

scholarly journals Protective Netting Improves Leaf-level Photosynthetic Light Use Efficiency in ‘Honeycrisp’ Apple Under Heat Stress

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1416-1422 ◽  
Author(s):  
Giverson Mupambi ◽  
Stefano Musacchi ◽  
Sara Serra ◽  
Lee A. Kalcsits ◽  
Desmond R. Layne ◽  
...  
Keyword(s):  
Heat Stress ◽  
Solar Radiation ◽  
Leaf Gas Exchange ◽  
Growing Season ◽  
High Light ◽  
Weather Data ◽  
Light Use Efficiency ◽  
Ambient Temperatures ◽  
Leaf Level ◽  
Use Efficiency

Globally, apple production often occurs in semiarid climates characterized by high summer temperatures and solar radiation. Heat stress events occur regularly during the growing season in these regions. For example, in the semiarid eastern half of Washington State, historic weather data show that, on average, 33% of the days during the growing season exceed 30 °C. To mediate some of the effects of heat stress, protective netting (PN) can be used to reduce the occurrence of fruit sunburn. However, the impacts of reduced solar radiation in a high light environment on light-use efficiency and photosynthesis are poorly understood. We sought to understand the ecophysiological response of apple (Malus domestica Borkh. cv. Honeycrisp) under blue photoselective PN during days with low (26.6 °C), moderate (33.7 °C), or high (38.1 °C) ambient temperatures. Two treatments were evaluated; an uncovered control and blue photoselective PN. Maximum photochemical efficiency of PSII, or photosystem II (Fv/Fm) was significantly greater at all measurement times under blue photoselective PN compared with the control on days with high ambient temperatures. Fv/Fm dropped below 0.79, which is considered the threshold for stress, at 1000 hr in the control and at 1200 hr under blue photoselective PN on a day with high ambient temperature. On days with low or moderate ambient temperatures, Fv/Fm was significantly greater under blue photoselective PN at 1400 hr, which coincided with the peak in solar radiation. ‘Honeycrisp’ apple exhibited dynamic photoinhibition as shown by the diurnal decline in Fv/Fm. Quantum photosynthetic yield of PSII (ΦPSII) was also generally greater under blue photoselective PN compared with the control for days with moderate or high ambient temperatures. Photochemical reflectance index (ΔPRI), the difference in reflectance between a stress-responsive and nonstress-responsive wavelength, was greater under PN compared with the control on the day with high ambient temperatures, with no differences observed under low or moderate ambient temperatures. Leaf gas exchange did not show noticeable improvement under blue photoselective netting when compared with the control despite the improvement in leaf-level photosynthetic light use efficiency. In conclusion, PN reduced incoming solar radiation, improved leaf-level photosynthetic light use efficiency, and reduced the symptoms of photoinhibition in a high-light, arid environment.

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