Variations in chlorophyll a/b and chlorophyll/carotenoid ratios are indicators of senescence, stress or damage to the photosynthetic apparatus and affect the normal course of plant biological processes. The aim of this work was to investigate the chlorophyll (a and b) and carotenoid content and ratios in the leaves of four Vitis vinifera L. table grape cultivars in the main phenophases of the annual biological cycle. During the annual cycle, the moisture content of the leaves decreased significantly (up to 21%), along with a reduction in leaf area and perimeter. Chlorophyll a and b showed a continuous accumulation until grape véraison, with lower values of the Chl a/b ratio at the beginning of the vegetative period. Carotenoids continued their biosynthesis until grape ripening (for another 30 days), at which stage there was a significant decrease in the chlorophyll/carotenoid ratio (2.62 ± 0.31). At véraison, peroxidase had the most intense activity (0.20 to 0.51 U/mg), possibly because of involvement in chlorophyll degradation, while total phenolic content started to decrease. Grape véraison could be regarded as the starting point of foliage senescence. Moreover, the relationship between total chlorophyll (by extraction) and chlorophyll content index (non-destructive method) was very significant (R 2 = 0.92). These results contribute to a better understanding of foliar pigment dynamics and the timing of their decline in order to define the behaviour of table grape cultivars during the annual biological cycle. INTRODUCTIONThe annual life cycle of grapevines is a process that takes place in the vineyard each year, beginning with bud burst in the spring and culminating with leaf fall in autumn, followed by winter dormancy (Creasy & Creasy, 2009). The annual life cycle comprises all morphological and biological changes with a periodic character through which the grapevine passes in a calendar year. These changes are called phenological stages (phenophases) and have a specific starting and ending time and a hereditary character (Wang et al., 2014). The occurrence and duration of phenological phases is influenced by climatic factors, and it should be noted that, under the same climatic conditions, the annual life cycle varies by cultivar (Jones & Davis, 2000). In the temperate continental climate, the annual cycle of grapevines lasts about 160 to 220 days.Chlorophylls (Chl) are probably the most important organic compounds on earth, as they are required for photosynthesis (Davies, 2004;Willows, 2004). Photosynthesis in plants is dependent upon capturing light energy in the pigment chlorophyll, and in particular chlorophyll a (Blankenship, 2014). Photosynthetic activity is a very intense process (5 to 11 μmol CO 2 /m 2 /s) that provides all the organic material needed for the growth and life activity of the plant (Popescu & Popescu, 2014). This is why photosynthesising cells have to contain large amounts of assimilatory pigments (up to 5% of total dry solids; Rabinowitch & Govindjee, 1969). In most species, the photos...
The use of antioxidants and antibacterials in food industry has become increasingly necessary to ensure the high quality of food. Grape pomace is the main by-product of winemaking industry that concentrates bioactive metabolites with more studied antioxidant activity and possible antibacterial activity. The grape pomace contains fragmented skin, broken cells, pulp remains, stalks and seeds with high amount of phenolic compounds due to their poor extraction during the winemaking process. Anthocyanins, catechins, flavonol glycosides, phenolic acids, alcohols and stilbenes have been identified among the compounds present in grape pomace. In this study, antibacterial activity against different pathogens (Escherichia coli ATCC 25922, Candida albicansATCC 90028, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923) was evaluated and the relation with polyphenols content and antioxidant activity of grape pomace from selected grapes from Iaşi vineyard was studied. The grape pomace samples were obtained after the fermentation process from the 2017 harvest of Sauvignon Blanc, Traminer, Busuioacă de Bohotin, Cabernet Sauvignon, Merlot, Fetească Neagră and Fetească Regală grape varieties. The antioxidant properties were evaluated using the DPPH method, FRAP assay and Folin Ciocalteu method. The content of resveratrol was quantified using an HPLC method. Samples with antioxidant activity showed the highest phenolics content. This study reveals that grape pomace is a potential source of natural antioxidant agents. The pomace extracts were tested to establish the effects on Gram-positive and Gram-negative bacteria. The analysed samples exhibited insignificant antibacterial activity and the method requires optimization. Grape marc represents an important source of resveratrol and other bioactive compounds that could be a valuable source of antioxidants for further utilization in food and pharmaceutical industry.
In Romania, as in many other countries, white cabbage is one of the most important vegetable crop species. The experiment was performed in the NE of the country during 2008-2009 in order to measure the impact of cultivar choice and pest control techniques on organic white cabbage [Brassica oleracea (L.) var. capitata f. alba (D.C.)]. This experiment included early, summer and autumn crops. The early crop compared four cultivars, the summer crop two cultivars, and the autumn crop three cultivars. The effect of various common organic pest control techniques was also measured. These techniques included: treatments with extract from neem (Azadirachta indica), potassium soap, Bacillus thuringiensis var. kurstaki toxins, application of a parasitic wasp (Trichogramma evanescens) and covering the crop with an agrotextile. Data were collected regarding the effect of cultivar selection and pest control technique on common local cabbage pests: cabbage flea beetle (Phyllotreta atra), cabbage fly (Delia brassicae), cabbage moth (Mamestra brassicae) and cabbage butterfly (Pieris brassicae). The highest yields for each respective growing season were obtained using the following combinations: Flavius agrotextile (early crop), Copenhagen Market agrotextile + 4 lha-1 azadirachtin + 12104 wasps/ha (summer crop) and Buzau 4 lha-1 azadirachtin (autumn crop).
Vine varieties react differently to the influence of environmental factors by decreasing or significantly intensifying the vigour of shoot growth, a biological reaction that also affects fertility and productivity. This article presents data on some agrobiological properties (vegetative growth of shoots, fertility and productivity) of some white wine varieties, created at the Research and Development Station for Viticulture and Vinification (R.D.S.V.V.) Odobești, Vrancea County, Romania) - Şarba, Băbească gri, Mioriţa and Vrancea, in the period 2020 - 2021. The data obtained were compared with the control variety Fetească regală. In Odobeşti vineyard, 2020 was much warmer than normal, characterized by a severely deficient rainfall regime resulting in atmospheric drought, followed by the gradual development of pedological drought. The vigour of shoots was negatively influenced by the climatic conditions of the vegetation period in 2020, the highest values being recorded for the varieties Șarba (159.6 cm) and Vrancea (141.5 cm), which showed significant positive differences, compared to the control variety. The fertility of the buds was lower in 2020, compared to 2021, the Vrancea variety being distinguished by higher potential fertility than the varieties Șarba, Băbească gri and Miorița, but lower potential fertility than the control variety. The absolute fertility coefficient (Cfa) had superunitary values for all varieties (1.07 - 1.50), and the relative fertility coefficient (Cfr) had subunitary values, except for the Vrancea variety (1.32). The varieties Șarba, Băbească gri and Miorița achieved an absolute productivity index (Ipa) superior to the control variety Fetească regală due to the higher average weight of the grapes, and the relative productivity index (Ipr) ranged from 199 for the Vrancea variety to 182 for the variety Șarba.
Chlorophyll content in leaves of 11 Vitis vinifera L. indigenous varieties (Iasi vineyard, Romania) was determined by two independent methods: spectrophotometry (extraction) and with a OptiSciences CCM-200 plus chlorophyll content meter (non-destructive method) with the aim of comparing the results. Also, this study was conducted to establish the values of chlorophyll a/ chlorophyll b and chlorophyll/carotenoid ratio in middle leaves of vine stocks, in the phenophase of progressive growing of shoots. Area and perimeter of leaves in this phenophase were determined. Total chlorophyll concentration in leaf extract varied from 0.67±0.01 mg/g f.w. to 1.00±0.03 mg/ g f.w., being highly correlated with the chlorophyll content index values (CCI) recorded by CCM-200 (R 2 =0.9839; p<0.001). Similar situation was identi ied in the case of the chlorophyll b and CCI correlation (R 2 =0.9638; p<0.001). Chlorophyll a/b ratio in leaf extract varied signi icantly depending on variety, ranging from 1.06±0.01 to 2.43±0.01, with a chlorophyll/carotenoid ratio reaching up to 3.19±0.08. Compared to spectrophotometry, CCM-200 plus affords fast, reliable, economical, non-destructive chlorophyll content measurement, however, providing no details regarding chlorophyll components and ratios.
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