Photosynthetica - Ahead of Print
Ecophysiological study of SiK impact on Castanea sativa Mill. tolerance to drought stress
A. CARNEIRO-CARVALHO, R. ANJOS, J. LOUSADA, T. MARQUES, T. PINTO, J. GOMES-LARANJO
Photosynthetica X:X | DOI: 10.32615/ps.2020.030
Drought is an abiotic stress that may be aggravated by climate changes with increasingly warmer and drier summers. This is a severe problem in the chestnut crop in Portugal due to its need for water during this time, which is essential for good formation and development of the fruit. Si fertilization is referenced by several authors as important in the tolerance of plants under drought. The experiments were carried out in the field trial and chestnuts were fertilized with 0, 5, 7.5, and 10 mM potassium silicate (SiK), which was applied to the soil and to the leaves and exposed to a non-irrigation and an irrigation phase during the summer. Results indicate...
Subtle changes in solar radiation under a green-to-red conversion film affect the photosynthetic performance and chlorophyll fluorescence of sweet pepper
H.I. YOON, J.H. KANG, W.H. KANG, J.E. SON
Photosynthetica X:X | DOI: 10.32615/ps.2020.057
Although spectrum conversion films are used to improve the photosynthetic efficiency and, ultimately, crop growth, the effects of the modified spectrum on photosynthetic traits in plants have not yet been sufficiently reported. The objective of this study was to investigate the changes in photosynthetic performance and chlorophyll fluorescence of sweet pepper (Capsicum annuum L.) under a green-to-red conversion (GtR) film. The GtR-modified spectrum increased the dry mass and decreased the petiole length. The photosynthetic light-response curves were significantly improved, and the gap of the maximum photosynthetic rates increased over time after...
Zinc and selenium as modulating factors of the anatomy and physiology of Billbergia zebrina (Bromeliaceae) during in vitro culture
J.P.R. MARTINS, A.F.C. SOUZA, L.C.A. RODRIGUES, P.C.S. BRAGA, A.B.P.L. GONTIJO, A.R. FALQUETO
Photosynthetica X:X | DOI: 10.32615/ps.2020.058
Deleterious effects induced by high zinc (Zn) concentrations can be alleviated with selenium (Se) co-exposure. Therefore, we analyzed the morphophysiological changes of Billbergia zebrina in response to Zn and Se co-exposure. Plants were cultured in media containing three Zn concentrations (0, 30, and 300 μM) combined with two Se concentrations (0 and 4 μM), for a total of six treatments. At 75 d of culture, the leaf anatomy, chlorophyll (Chl) a fluorescence, and contents of photosynthetic pigments (Chl) and nutrients were analyzed. The total Chl content declined with rising Zn concentrations. Plants cultured with Se presented...
Upregulation of mitochondrial alternative oxidase pathway protects photosynthetic apparatus against photodamage under chilling stress in Rumex K-1 leaves
D. CHENG, H. GAO, L. ZHANG
Photosynthetica X:X | DOI: 10.32615/ps.2020.060
This study aimed to clarify the role of mitochondrial alternative oxidase (AOX) pathway upregulation in photoprotection under chilling stress in Rumex K-1 leaves. Malate-oxaloacetate shuttleꞌs activity and AOX pathwayꞌs capacity were synchronously enhanced with light intensity increase both in control and chilling-treated leaves. Besides, the AOX pathway was upregulated more significantly when irradiated by light in chilling-treated leaves than that of control. These results suggested that excess reducing equivalents generated by photosynthesis were exported from chloroplasts and oxidized by the AOX pathway at a potentially higher...
Ginkgo biloba and Helianthus annuus show different strategies to adjust photosynthesis, leaf water relations, and cell wall composition under water deficit stress
M. ROIG-OLIVER, M. NADAL, J. BOTA, J. FLEXAS
Photosynthetica X:X | DOI: 10.32615/ps.2020.063
Cell wall thickness (Tcw) determines photosynthesis and leaf elasticity. However, only a few studies in angiosperms addressed cell wall composition implication in regulating photosynthesis and leaf water relations through mesophyll conductance (gm) and bulk modulus of elasticity (ε) adjustments, respectively. Thus, we compared the phylogenetically distant Ginkgo biloba L. and Helianthus annuus L. under control and water deprivation to study the relationship between changes in cell wall composition (cellulose, hemicelluloses, and pectins) with gm and ε. Although no changes...
The carbon reactions of photosynthesis: role of lectins and glycoregulation
A.M. NONOMURA, D. SHEVELA, S.S. KOMATH, K.Y. BIEL, G. GOVINDJEE
Photosynthetica X:X | DOI: 10.32615/ps.2020.064
Modulation of glycoregulation in agriculture is reviewed here with emphasis on the elucidation of previously unknown pathways involving vacuolar lectins as well as a bypass of lectins that direct free sugars toward productivity. The reversible binding sequences of the endogenous lectin cycle are compared to an induced lectin bypass, as follows. (1) In the cycle, carbohydrate ligands, with similar binding specificities that compete for binding sites on lectins, are involved in the natural cycle of sugar exchanges. (2) For the bypass, tightly bound ligands that occupy lectins prevent free sugars from binding, making them available for productivity....
Differential response of photosystem II and I photochemistry in leaves of two Crambe abyssinica Hochst lineages submitted to water deficit
P.C.S. BRAGA, J.P.R. MARTINS, R. BONOMO, R.M. BORGES, J.V.G. SILVA, A.R. FALQUETO
Photosynthetica X:X | DOI: 10.32615/ps.2020.065
Water stress is one of the most important abiotic factors affecting plants worldwide. This study compared the photochemical responses of two lineages of Crambe abyssinica (FMS CR 1307 and 1326) under water deficit (WD) conditions. The relative water content (RWC), stomatal conductance, chlorophyll (Chl) index, and Chl a fluorescence were evaluated. FMS CR 1326 showed greater reductions in RWC under WD. The FMS CR 1307 showed greater reductions in the connectivity of energy (L-band) and electron transfer from the oxygen-evolving complex (K-band), followed by a lower ability to maintain the reduction of plastoquinone. However, the increased...
Responses of photosynthetic characteristics and growth in rice and winter wheat to different elevated CO2 concentrations
C. LIU, Z.H. HU, L.F. YU, S.T. CHEN, X.M. LIU
Photosynthetica X:X
This study investigated the effects of different elevated CO2 concentrations [ambient CO2 concentration (CK), CK plus 40 μmol mol-1 (T1), CK plus 200 μmol mol-1 (T2)] on photosynthetic characteristics and growth of rice (Oryza sativa L.) and winter wheat (Triticum aestivum L.). The results showed that T2 treatment decreased the net photosynthetic rate and leaf nitrogen content (LNC) but increased the light-saturated net photosynthetic rate of rice. Additionally, T2 treatment increased biomass accumulation and yield in both rice and winter wheat...