Photosynthetica, 2020 (vol. 58), issue 5

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 2020, 58(5):1068-1077 | 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...

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 2020, 58(5):1078-1089 | 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...

The carbon reactions of photosynthesis: role of lectins and glycoregulation

A.M. NONOMURA, D. SHEVELA, S.S. KOMATH, K.Y. BIEL, G. GOVINDJEE

Photosynthetica 2020, 58(5):1090-1097 | 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....

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 2020, 58(5):1098-1106 | DOI: 10.32615/ps.2020.063

Cell wall thickness (T_cw) 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 (g_m) 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 g_m and ε. Although no changes...

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 2020, 58(5):1107-1115 | 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...

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 2020, 58(5):1116-1121 | 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...

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 2020, 58(5):1122-1129 | 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 2020, 58(5):1130-1140 | DOI: 10.32615/ps.2020.066

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...

External potassium mediates the response and tolerance to salt stress in peanut at the flowering and needling stages

X.L. SHI, D.Y. ZHOU, P. GUO, H. ZHANG, J.L. DONG, J.Y. REN, C.J. JIANG, C. ZHONG, X.H. ZHAO, H.Q. YU

Photosynthetica 2020, 58(5):1141-1149 | DOI: 10.32615/ps.2020.070

Potassium (K) is an essential macronutrient that plays an important role in abiotic stress tolerance. A pot experiment was carried out to identify the potential role of potassium fertilizer in alleviating salt stress in peanut. The results showed that salt stress significantly decreased plant height, dry mass, photosynthetic pigments, the photosynthetic rate, and stomatal conductance, but increased the Na⁺/K⁺ ratio, total sugars, and the leaf salinity hazard coefficient in two peanut varieties. However, the application of potassium significantly alleviated the harmful effect of salt by improving the contents of photosynthetic...

The effects of pumpkin rootstock on photosynthesis, fruit mass, and sucrose content of different ploidy watermelon (Citrullus lanatus)

P.M. YANG, S.T. HE, L.N. JIANG, X.J. CHEN, Y.F. LI, J.G. ZHOU

Photosynthetica 2020, 58(5):1150-1159 | DOI: 10.32615/ps.2020.068

Pumpkin rootstock affects watermelon scion growth, fruit yield, and quality, but the mechanisms of related key enzymes and photosynthesis remain unclear. In this study, net photosynthetic rate (P_N), chlorophyll (Chl) fluorescence parameters, fruit mass and sugar accumulation, and related key enzyme activities were determined during the fruit development stage in diploid and triploid watermelon lines and corresponding pumpkin rootstock-grafted lines. The results showed that pumpkin rootstock increased P_N and Chl fluorescence parameters of diploid and triploid watermelon, indicating that pumpkin rootstock could increase...

Relationship of fertilizer and periodic drought on biomass allocation in greenhouse-grown sunflower

Z.Y. LI, B.L. DUNN, C. FONTANIER

Photosynthetica 2020, 58(5):1160-1166 | DOI: 10.32615/ps.2020.061

The objective was to analyze organ plasticity in biomass allocation in response to limited resources and its influence on commercial traits of potted sunflower production. Although drought dramatically increased net photosynthetic rate and water-use efficiency, total leaf area, leaf dry mass, and total dry mass with drought stress decreased at rates of 20.9, 21.8, 23.0, and 9.9%, respectively. Irrigation positively affected specific leaf area, stem mass fraction, and root mass fraction. Adversely, fertilizer had a negative effect on stem mass fraction, root mass fraction, and root/shoot ratio. Interestingly, leaf mass fraction was not affected by them....

Differences in leaf anatomy, photosynthesis, and photoprotective strategies in the yellow-green leaf mutant and wild type of Rosa beggeriana Schrenk

S.H. YANG, J.J. WEI, F. YAN, R.D. JIA, X. ZHAO, Y. GAN, H. GE

Photosynthetica 2020, 58(5):1167-1177 | DOI: 10.32615/ps.2020.059

Although the underlying mechanisms of chlorophyll biosynthesis have been intensively deciphered in model plants, leaf color mutants have not yet been fully studied in woody species. In this study, leaf anatomy, diurnal changes in photosynthesis and photoprotection were investigated in the yellow-green leaf (ygl) mutant of Rosa beggeriana. Chloroplast ultrastructure, pigment biosynthesis, and photosynthesis were impaired and led to photoinhibition at noon in the ygl mutant. The negative changes in leaf anatomy increased the risk of excess light absorption in the mutant. Moreover, the ygl mutant preferred to consume the excited...

Disturbance mechanism of coal mining subsidence to typical plants in a semiarid area using O-J-I-P chlorophyll a fluorescence analysis

Y. LIU, S.G. LEI, X.Y. CHEN, M. CHEN, X.Y. ZHANG, L.L. LONG

Photosynthetica 2020, 58(5):1178-1187 | DOI: 10.32615/ps.2020.072

The response of individual plants to coal mining subsidence disturbance reflects the micro-ecological mechanism implied in the macro-response, which is the basis of studying the rule of vegetation disturbance of large-scale coal mining. In this study, O-J-I-P chlorophyll a fluorescence analysis was used to diagnose the disturbance mechanism of typical individual plants by coal mining subsidence in a semiarid area. The results showed that the groundwater level and soil water content decreased due to the disturbance of coal mining subsidence and the plant growth was affected by drought stress. The rapid chlorophyll fluorescence induction curve...

Silencing of the receptor-like cytoplasmic kinase gene TaRKL1 reduces photosynthetic capacity in wheat

Y. YING, F.F. LIU, G.P. LI, Q. ZHENG, B. LI, Z.S. LI, J.F. CHENG, H.W. LI

Photosynthetica 2020, 58(5):1188-1199 | DOI: 10.32615/ps.2020.069

To explore the role of receptor-like kinases in the regulation of photosynthesis, an uncharacterized TaRKL1 encoding a receptor-like cytoplasmic kinase was investigated in Triticum aestivum cv. Xiaoyan 101 with Barley stripe mosaic virus-induced gene silencing system (BSMV-VIGS). The results showed that the CO₂ assimilation rate, stomatal conductance, and transpiration rate were significantly lower in the BSMV:TaRKL1 plants than those in the BSMV:γ00 plants (control). Moreover, the maximum photochemical efficiency and electron transport flux decreased while the dissipated energy flux was enhanced...

Effect of simultaneous shade and drought stress on morphology, leaf gas exchange, and yield parameters of different soybean cultivars

I. SHAFIQ, S. HUSSAIN, B. HASSAN, M. SHOAIB, M. MUMTAZ, B. WANG, A. RAZA, A. MANAF, M. ANSAR, W. YANG, F. YANG

Photosynthetica 2020, 58(5):1200-1209 | DOI: 10.32615/ps.2020.067

An interactive effect of simultaneous shade and drought stress on drought-tolerant and drought-sensitive cultivars of soybean was studied. As drought stress intensified, the net photosynthetic rate decreased in both cultivars due to reduced leaf area, relative water content, transpiration rate, stomatal conductance, chlorophyll content, and Rubisco activity which ultimately led to yield reduction. Moreover, the chlorophyll fluorescence parameters also decreased. Interestingly, a moderate shade was found helpful in alleviating the adverse effects of drought stress, specifically in resistant cultivar N12 where seed yield improved significantly under...

Phenolic acids inhibit the photosynthetic productivity of poplar

K. LI, T. ZHANG, H. LI, L.D. ZHANG, F. LI

Photosynthetica 2020, 58(5):1210-1216 | DOI: 10.32615/ps.2020.071

Barriers to continuous cropping of poplar plantations are closely related to the accumulation of phenolic acids in the soil. The purpose of this study was to explore the mechanism through which phenolic acid stress affects poplar productivity. The results showed that phenolic acids had a significant inhibitory effect on the photosynthesis of poplar. The inhibition of photosynthesis due to phenolic acids occurred mainly because, during electron transfer at the PSII reaction center, the primary quinone acceptor of PSII (Q_A) in the oxidized state was reduced, and excess light energy was lost in the form of heat dissipation; thus, poplar productivity...

Photosynthetic machinery and antioxidant status of wheat genotypes under drought stress followed by rewatering

D.R. ALIYEVA, L.M. AYDINLI, A.N. PASHAYEVA, I.S. ZULFUGAROV, I.M. HUSEYNOVA

Photosynthetica 2020, 58(5):1217-1225 | DOI: 10.32615/ps.2020.074

Land plants shorten their vegetation period during water deficiency. Under water stress, wheat plants undergo several changes at the morphophysiological level. We tried to elucidate the role of the morphophysiological parameters and the photosynthetic machinery in response to drought followed by rewatering. Therefore, some morphophysiological traits of two bread wheat genotypes (drought-tolerant Gobustan, drought-sensitive Tale 38) were studied. The H₂O₂ content increased under drought in both genotypes but recovered in the Gobustan genotype after rewatering. The isozymes of peroxidase manifested dynamic changes under drought....

Effect of drought and heat stresses on photosynthesis, pigments, and xanthophyll cycle in alfalfa (Medicago sativa L.)

C. XU, C.G. HE, Y.J. WANG, Y.F. BI, H. JIANG

Photosynthetica 2020, 58(5):1226-1236 | DOI: 10.32615/ps.2020.073

Climate changes severely influence photosynthetic activity of plants. Studies on the combined effect of drought and heat stress on photosynthesis, pigments, and xanthophyll cycle particularly in alfalfa (Medicago sativa L.) are limited. Thus, this study investigated the combined effects of drought and heat stress in two alfalfa varieties ('Deqin' and 'Algonguin'). Results revealed that the values of the net photosynthetic rate demonstrated a significantly decreasing tendency under stresses. The effect of stresses on ribulose 1,5-bisphosphate carboxylase activity in both varieties showed a trend of first declining and then rising. Meanwhile,...