‘Chambourcin’ grapevine (Vitis vinifera Vitis L.) berries display sustained post-veraison accumulation of oxalic acid

SUMMARY

A substantial accumulation of organic acids (OAs) occurs during pre-veraison grape berry development, which results in low pH conditions and contributes to the organoleptic properties of the fruit. The main OAs in most grape berries are tartaric acid (TA) and malic acid (MA). MA is accumulated via a primary metabolic shunt, whereas TA is accumulated via ascorbic acid (AA; vitamin C) metabolism. Oxalic acid (OX) is also derived from AA in competition with TA, and results from a cleavage between the second and third carbon atoms. Oxalic acid is subsequently biomineralised as calcium oxalate crystals in idioblast cells. We have examined the biosynthesis of TA, MA, and OX during grape berry development in four grapevine cultivars. We show that in the Vitis vinifera L. Vitis L. complex inter-specific hybrid, ‘Chambourcin’, there is a high capacity to accumulate OX during post-veraison fruit development. OX content increased from approx. 1 mg g^–1 to 3 mg g^–1 berry fresh weight between 14 and 16 weeks post-anthesis, resulting in OX levels that were similar to the MA levels in mature fruit. Whether OX accumulation occurs due to increased biomineralisation or biosynthesis, our results show that ‘Chambourcin’ grape berries represent the only documented case of post-veraison accumulation of OX.     

Detection of variation among clonal selections of grapevine (Vitis vinifera L.) ‘Kishmish Chernyi’ by AFLP analysis

Summary

Clonal selection is an important method for varietal improvement in grapevine. Ampelometric and morphological markers fail to differentiate clones from their parent genotype. Molecular markers offer the opportunity to identify the clonal material. In this study, five clones of the grapevine variety ‘Kishmish Chernyi’ were analysed using microsatellite (SSR) and AFLP markers. These clones differed significantly in their bunch characteristics including berry size, shape, and colour. Microsatellite (SSR) analysis using 24 primers could not distinguish between these clones. The allele profiles of the clones and the parent variety were identical. AFLP analysis using 13 primer pair combinations yielded 592 markers ranging in size from 50 – 500 bp. Of these, 79 markers (13%) were polymorphic. The majority of the polymorphic markers (75/79) were detected in the clone ‘Sharad Seedless’. Three AFLP primer combinations detected unique markers in three clones which could be useful for future identification.     

Effects of the application of ‘cash’ on the growth,fruit yield,and nutrient status of tomato (Solanum lycopersicum L.) grown in reclaimed saline soil

Summary

The effects of ‘cash’ [a novel 2:5:1 (w/w/w) mixture of calcium sulphate, ground sunflower heads, and humic acid] as a soil amendment on the growth, fruit yield, and leaf nutrient status of tomato (Solanum lycopersicum L.) grown on reclaimed saline soil (EC = 9.4 dS m^–1) were investigated. A glasshouse experiment was performed in a completely randomised design with six treatments (0, 10, 20, 30, 40, or 50 g ‘cash’ kg^–1 soil) each with four replicates. The results indicated that ‘cash’ increased both the shoot dry weight (DW) plant^–1 and the root DW plant^–1, the free proline contents of leaves, and leaf chlorophyll contents. The use of ‘cash’ also increased the number of fruit plant^–1, fruit yield pot^–1, and fruit vitamin C contents, although total soluble solids (TSS) contents were not affected. The contents of nitrogen (N), potassium (K), and calcium (Ca), and the Ca:Na ratios of leaf tissues increased with all application rates of ‘cash’. Leaf phosphorus (P) contents showed no response to any applied level of ‘cash’. Leaf sodium (Na) contents declined gradually with an increase in the level of ‘cash’ applied to the soil. We concluded that ‘cash’ has a pronounced positive effect on the growth and fruit yield of tomato plants grown in reclaimed saline soil. ‘Cash’ therefore has the potential to be used as a soil amendment for vegetable crops such as tomato to overcome the adverse effects of salinity in newly-reclaimed soils.     

Variation in Total Phenolic Compounds,Anthocyanin and Monoterpene Content of ‘Muscat Hamburg’ Table Grape Variety (V. vinifera L.) as Affected by Cluster Thinning and Early and Late Period Basal Leaf Removal Treatments

Cluster thinning (CT) and basal leaf removal (BLR) are common canopy management practices used in grape growing. In recent years, novel viticultural techniques have been evolved all around the world to decrease costs of yield management, causing improvement in grape quality. The purpose of this study was to evaluate the effects of CT and early and late period BLR treatments on yield and quality components of cv. ‘Muscat Hamburg’. While BLR treatments were performing at pre-bloom (PB, early), berry set (BS), berries with pea size (PS), verasion (V), CT treatment was conducted at verasion period. Compared to Control, while the total phenolic compounds content, total anthocyanin content, free volatile terpenes content and potentially volatile terpenes content were made better by CT treatment and BLR treatments applied from berry set to verasion period gradually raised all these quality components.