Biotransformation of C13-norisoprenoids and monoterpenes by a cell suspension culture of cv. Gamay (Vitis vinifera)

A cell suspension culture of cv. Gamay was studied for its ability to metabolize two different C₁₃-norisoprenoidic volatiles, β-ionone and dehydrovomifoliol, together with monoterpenes, geraniol and linalool, biogenetically common pathways sharing compounds. β-Ionone was totally metabolized leading to fourteen norisoprenoidic volatiles oxygenated mainly at carbons 3 or 4 of the cyclohexane ring or reduced at side chain. The biotransformation of dehydrovomifoliol was at a lesser extent, giving rise to oxygenated and reduced derivatives. The norisoprenoidic metabolites were present both under free and glycosylated forms. Geraniol and linalool were also metabolized, leading to several free and glycosylated compounds. S. Mathieu, J. Wirth contributed equally to the work and should be considered joint first authors. A short part of this paper was published at the proceedings of the 10th Weurman Flavour Research Symposium, Flavour Research at the Dawn of the Twenty-first Century, J.-L.Le Quere, P.-X.Etievant, Editors; Lavoisier,2003/Intercept Ltd, 2003.     

Relationship of Grapevine Yield and Growth to Nematode Densities

Yield, growth, and vigor of individual grape vines were correlated with nematode population densities in a series of California vineyards. In a Hanford sandy loam soil, Xiphinema americanum densities showed negative correlations with yield, growth, and vigor of vines. When vines were categorized according to vigor, X. americanurn densities had little relationship to yield of high-vigor vines, but were negatively correlated with yield of low-vigor vines. Densities of Paratylenchus harnatus were positively correlated with yield, growth, and vigor of vines. Correlations between Meloidogyne spp. densities and vine performance were variable, even when the vines were separated according to soil type and plant vigor. Densities of Meloidogyne spp. populations were generally higher on coarser-textured, sandy soils and the vines were less vigorous there. Densities of P. hamatus were greater in fine-textured soils.     

Programmed accumulation of LEA-like proteins during desiccation and cold acclimation of overwintering grape buds

Molecular investigation of the process of cold acclimation in woody plants has been limited by the superimposition of dormancy-related events on the process of cold tolerance development. To address this limitation, we have used the grape Vitis labruscana L. ev. Concord to develop a system in which the developmental programme of dormancy can be induced seperately from cold acclimation. Using this system we have characterized differential accumulation of several proteins in grape buds during the normally superimposed endodormancy and cold acclimation programmes, and in buds which have entered only the endodormancy programme. A set of 47 kD proteins accumulated during endodormancy without cold acclimation to a level similar to that found in endodormant and cold-acclimated buds, but without any associated increase in bud cold-acclimation level. However, a 27 kD LEA-like protein accumulated only in cold acclimated buds. We conclude that expression of the 47 kD glycoprotein is endodormancy-related, but is not strictly related to the development of cold acclimation, while the 27 kD protein appears to be more specific to cold acclimation. In addition to strengthening the association of LEA-like proteins with cold acclimation, this system allows more specific assessment of cold acclimation-associated phenomena in overwintering buds.     

Changes in Salicylic and Abscisic Acid Contents during Heat Treatment and Their Effect on Thermotolerance of Grape Plants

Heat treatment (38°C) of young grape plants (Vitis vinifera L., cv. Jingxiu) or leaf spraying with 100 µM salicylic acid (SA) increased leaf thermotolerance. Both treatments led to an increase in ABA content and a decrease in lipoxygenase (LOX) activity. ABA content showed a drastic rise by one hour after treatments and then sharply declined while LOX activity continuously decreased. In the course of heat treatment of grape plants, endogenous SA level and phenylalanine ammonia-lyase activity rapidly increased during the first hour, then declined. These results showed that endogenous SA and ABA can be involved in grape plant response to heat treatment resulted in improved thermotolerance.From Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 578–583.Original English Text Copyright © 2005 by Wang, Huang, Liu, Zhan.The text was submitted by the authors in English.     

Leaf movement,stress avoidance and photosynthesis in Vitis californica

Summary Gas exchange and chlorophyll fluorescence techniques were used to evaluate the hypothesis that leaf movement in Vitis californica Benth. (California wild grape) allows a compromise between sunlight interception and stress damage in order to maximize photosynthetic carbon gain over the life of the leaf. Leaves that were restrained horizontally tolerated their increased radiation loads if critical temperatures were not exceeded. Reductions in photosynthetic capacity and the F _V/F _M fluorescence ratio only occurred in leaves that attained high temperatures. Leaf orientation and canopy position were important determinants of leaf temperature. These results indicate that excessive leaf temperature, not high PFD, can be a principle cause of reduced carbon gain and senescence in this species in the wild. Leaf movement appears to protect photosynthetic components in midsummer.