scholarly journals Relationship between photochemical efficiency of photosystem II and the photochemical reflectance index of mango tree: merging data from different illuminations, seasons and leaf colors

2010 ◽  
Vol 30 (4) ◽  
pp. 469-478 ◽  
Author(s):  
J. H. Weng ◽  
L. H. Jhaung ◽  
R. J. Lin ◽  
H. Y. Chen
2012 ◽  
Vol 34 (4) ◽  
pp. 1245-1255 ◽  
Author(s):  
Cicero Cartaxo de Lucena ◽  
Dalmo Lopes de Siqueira ◽  
Hermínia Emilia Prieto Martinez ◽  
Paulo Roberto Cecon

This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs)/(Fm')], D = (1- Fv'/Fm') and ETR = (ΦPSII×PPF×0,84×0,5) were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm) were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.


2007 ◽  
Vol 37 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Denize Caranhas de Sousa Barreto ◽  
José Francisco de Carvalho Gonçalves ◽  
Ulysses Moreira dos Santos Júnior ◽  
Andreia Varmes Fernandes ◽  
Adriana Bariani ◽  
...  

The rosewood (Aniba rosaeodora Ducke) is a native tree species of Amazon rainforest growing naturally in acidic forest soils with reduced redox potential. However, this species can also been found growing in forest gaps containing oxide soils. Variations in the forms of mineral nitrogen (NO3- or NH4+) may be predicted in these different edaphic conditions. Considering that possibility, an experiment was carried out to analyze the effects of different NO3-:NH4+ ratios on the growth performance, mineral composition, chloroplastid pigment contents, photochemical efficiency photosystem II (PSII), and nitrate redutase activity (RN, E.C.1.6.6.1) on A. rosaeodora seedlings. Nine-month-old seedlings were grown in pots with a washed sand capacity of 7.5 kg and submitted to different NO3-:NH4+ ratios (T1 = 0:100%, T2 = 25:75%, T3 = 50:50%, T4 = 75:25%, and T5 = 100:0%). The lowest relative growth rate was observed when the NO3-:NH4+ ratio was equal to 0:100%. In general, high concentrations of NO3- rather than NH4+ favored a greater nutrient accumulation in different parts of the plant. For the chloroplastid pigment, the highest Chl a, Chl b, Chl tot, Chl a/b and Chl tot/Cx+c contents were found in the treatment with 75:25% of NO3-:NH4+, and for Chl b and Cx+c it was observed no difference. In addition, there was a higher photochemical efficiency of PSII (Fv/Fm) when high NO3- concentrations were used. A linear and positive response for the nitrate reductase activity was recorded when the nitrate content increased on the culture substrate. Our results suggest that A. rosaeodora seedlings have a better growth performance when the NO3- concentrations in the culture substrate were higher than the NH4+ concentrations.


Fagopyrum ◽  
2021 ◽  
Vol 38 (1) ◽  
pp. 15-23
Author(s):  
Aleksandra Golob ◽  
Neja Luzar ◽  
Mateja Germ

Common buckwheat and Tartary buckwheat were grown in Slovenia outdoors at different elevations – 300 m, 600 m and 1180 m a.s.l. Both species were foliarly treated with selenium twice (in the vegetative phase and in the flowering phase). The effects of Se treatment and different growing locations on selected biochemical, physiological and anatomical traits were monitored. In Se treated common buckwheat, amount of chlorophylls was higher in plants from Ljubljana (the lowest elevation – 300 m a.s.l.) than in plants grown in Podbeže (600 m a.s.l.), whereas in control group, plants grown in Ljubljana contained more chlorophylls than plants from Javorje (the highest elevation – 1180 m a.s.l.). In both buckwheat species, Se alone did not affect amount of chlorophylls in any of location. In Se treated common buckwheat plants, the amount of UV absorbing compounds was the highest in plants, grown at the highest elevation. In common buckwheat, Se lowered the number of CaOx in plants, grown in Javorje. Conditions at different elevations, as well as treatments with Se, did not affect potential and effective photochemical efficiency of Photosystem II. Keywords: common buckwheat, Tartary buckwheat, elevation, selenium, morphological characteristics, biochemical characteristics


2017 ◽  
Vol 55 (4) ◽  
pp. 664-670 ◽  
Author(s):  
R. L. Xue ◽  
S. Q. Wang ◽  
H. L. Xu ◽  
P. J. Zhang ◽  
H. Li ◽  
...  

Toxics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 36
Author(s):  
Ilektra Sperdouli ◽  
Ioannis-Dimosthenis S. Adamakis ◽  
Anelia Dobrikova ◽  
Emilia Apostolova ◽  
Anetta Hanć ◽  
...  

Salvia sclarea L. is a Cd2+ tolerant medicinal herb with antifungal and antimicrobial properties cultivated for its pharmacological properties. However, accumulation of high Cd2+ content in its tissues increases the adverse health effects of Cd2+ in humans. Therefore, there is a serious demand to lower human Cd2+ intake. The purpose of our study was to evaluate the mitigative role of excess Zn2+ supply to Cd2+ uptake/translocation and toxicity in clary sage. Salvia plants were treated with excess Cd2+ (100 μM CdSO4) alone, and in combination with Zn2+ (900 μM ZnSO4), in modified Hoagland nutrient solution. The results demonstrate that S. sclarea plants exposed to Cd2+ toxicity accumulated a significant amount of Cd2+ in their tissues, with higher concentrations in roots than in leaves. Cadmium exposure enhanced total Zn2+ uptake but also decreased its translocation to leaves. The accumulated Cd2+ led to a substantial decrease in photosystem II (PSII) photochemistry and disrupted the chloroplast ultrastructure, which coincided with an increased lipid peroxidation. Zinc application decreased Cd2+ uptake and translocation to leaves, while it mitigated oxidative stress, restoring chloroplast ultrastructure. Excess Zn2+ ameliorated the adverse effects of Cd2+ on PSII photochemistry, increasing the fraction of energy used for photochemistry (ΦPSII) and restoring PSII redox state and maximum PSII efficiency (Fv/Fm), while decreasing excess excitation energy at PSII (EXC). We conclude that excess Zn2+ application eliminated the adverse effects of Cd2+ toxicity, reducing Cd2+ uptake and translocation and restoring chloroplast ultrastructure and PSII photochemical efficiency. Thus, excess Zn2+ application can be used as an important method for low Cd2+-accumulating crops, limiting Cd2+ entry into the food chain.


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