Je Jones

Non-structural carbohydrates in woody plants compared among laboratories

Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about plant responses to environmental conditions. Laboratories publishing estimates of NSC of woody plants use many different methods to evaluate NSC. We asked whether NSC estimates in the recent literature could be quantitatively compared among studies. We also asked whether any differences among laboratories were related to the extraction and quantification methods used to determine starch and sugar concentrations. These questions were addressed by sending sub-samples collected from five woody plant tissues, which varied in NSC content and chemical composition, to 29 laboratories. Each laboratory analyzed the samples with their laboratory-specific protocols, based on recent publications, to determine concentrations of soluble sugars, starch and their sum, total NSC. Laboratory estimates differed substantially for all samples. For example, estimates for Eucalyptus globulus leaves (EGL) varied from 23 to 116 (mean = 56) mg g(-1) for soluble sugars, 6-533 (mean = 94) mg g(-1) for starch and 53-649 (mean = 153) mg g(-1) for total NSC. Mixed model analysis of variance showed that much of the variability among laboratories was unrelated to the categories we used for extraction and quantification methods (method category R(2) = 0.05-0.12 for soluble sugars, 0.10-0.33 for starch and 0.01-0.09 for total NSC). For EGL, the difference between the highest and lowest least squares means for categories in the mixed model analysis was 33 mg g(-1) for total NSC, compared with the range of laboratory estimates of 596 mg g(-1). Laboratories were reasonably consistent in their ranks of estimates among tissues for starch (r = 0.41-0.91), but less so for total NSC (r = 0.45-0.84) and soluble sugars (r = 0.11-0.83). Our results show that NSC estimates for woody plant tissues cannot be compared among laboratories. The relative changes in NSC between treatments measured within a laboratory may be comparable within and between laboratories, especially for starch. To obtain comparable NSC estimates, we suggest that users can either adopt the reference method given in this publication, or report estimates for a portion of samples using the reference method, and report estimates for a standard reference material. Researchers interested in NSC estimates should work to identify and adopt standard methods.

Viticulture for Sparkling Wine Production: a Review

The current understanding of the influences of climate and viticultural practices on fruit quality at harvest and on sparkling wine quality is reviewed. Factors such as variety, clone, planting density, pruning method, local climate and soils, and current and future climate warming are discussed in the context of achieving a desired harvest quality. A common observation was the relatively less intensive viticultural management applied to grapes destined for sparkling wines compared to table wines throughout the world. Few studies have focused on management of fruit specifically for sparkling wine production. Given that it is accepted that a lower pH, higher titratable acidity, and lower soluble sugars than table wine are considered desirable for sparkling wine production, the literature from viticultural studies for table wines which influence these desired fruit quality parameters has been reported. Specific findings on canopy management, leaf removal, and yield manipulation for the production of table wines indicate potential for application and development to optimize fruit for the production of sparkling wines. Fruit quality targets are remarkably uniform across international growing regions but distinct combinations of variety, clone, and management are currently used to arrive at those targets. Further, studies of viticultural management, particularly those that alter cluster temperature and exposure to incident light, yield manipulation, and fruit quality are likely to best inform production techniques that result in fruit quality ideal for the production of premium sparkling wines. New challenges include the need for increasing mechanization to maintain cost-effective production and climate warming, which affects the production of fruit for premium sparkling production in terms of flavor development and high acidity. Current trends include the diversification of growing regions to cooler regions that enable the production of high acid fruit and increased exploration of alternative varieties and clones that are better suited to a warmer climate.

A statistical model to estimate bud fruitfulness in Pinot noir

A statistical model to estimate and describe bud fruitfulness in Pinot noir in cool environments was developed. The study compared Pinor noir fruitfulness at three different sites during winter dormancy by light microscopy and actual fruitfulness established three weeks after budburst. Strong differences were observed between inflorescence primordia counts and actual inflorescence number after budburst. When examined microscopically, fruitfulness was evenly distributed along the cane with the exception of the first two nodes, which were significantly lower. In contrast, actual fruitfulness after budburst showed site differences and interactions between fruitfulness and node position. Cane starch was a significant predictor for inflorescence count.

Effect of frost damage and pruning on current crop and return crop of Pinot Noir

Abstract In October 2006, much of the wine-growing area in Tasmania was affected by a series of some of the worst frost events in more than 30 years. Widespread damage left vineyards with blackened shoots and the prospect of a considerably smaller crop, with later maturing bunches from secondary buds contributing to poorer quality wine. In a commercial, spur-pruned Pinot Noir planting, treatments intended to encourage and manipulate secondary bud-burst are imposed and effects on yield recorded. Treatments are imposed 10 days after the frost and include: (i) an untreated control (control) with all damaged tissue left in place; (ii) frost-damaged tissue removed (light pruning); (iii) frost-damaged tissue removed and original spur trimmed back to one bud (medium pruning); and (iv) original (damaged) shoot removed back to compound bud on the spur (heavy pruning). Pruning treatment responses for season 2006–07 show that heavy pruning reduces the current crop with no useful gain in uniformity of ripening. The medium and heavy pruning treatments also reduce pruning weights at the end of the season and all post-frost pruning treatments result in a smaller inflorescence primordia size in dormant buds dissected at the beginning of commercial pruning. In the 2007–08 vintage, the untreated control and the medium pruning treatment have significantly lower bunch numbers than the other treatments. There is also a significant effect of terrain elevation on total yield and the number of bunches in the frost year, with increasing damage lower in the inversion. This gradation in damage does not have carry-over effects into the second season. The results indicate that none of the pruning treatments tested have clear benefits for current or subsequent season production, and that a prescriptive approach to pruning should be avoided when the level of frost damage is inconsistent across vines.