Relationships between carbohydrates and reproductive development in chardonnay grapevine: impact of defoliation and fruit removal treatments during four successive growing seasons

Abstract

<p style="text-align: justify;"><strong>Aim</strong>: The present study was conducted in grapevines to evaluate the influence of source/sink disturbance on reserve restoration in the entire plant (trunk, roots) and the consequences on reproduction, yield, sugar yield, potential alcohol content and total acidity over four successive years of treatment.</p><p style="text-align: justify;"><strong>Methods and results</strong>: At véraison, either total defoliation or total fruit removal was performed on Chardonnay plants grown in vineyards. The impact was measured each year on reproductive parameters and after four years on both plant weight and carbohydrate content. Defoliation induced an alteration in carbohydrate distribution in the entire plant, as revealed by decrease of starch content and parallel increase of soluble sugar content. These modifications affected the number of inflorescences/clusters per plant the year after. By contrast, fruit removal resulted in a significant increase of carbohydrate reserves in the whole plant, although the efficiency of sexual reproduction was not improved the year after.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Results confirm the close correlation between carbohydrate reserves and the efficiency of sexual reproduction. Moreover, grapevine is able to adapt the number of both inflorescences and flowers according to the amount of available carbohydrate reserves in perennial organs.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The quality of the crop is affected by defoliation, as shown by the decrease in yield and sugar yield. However, the impact on potential alcohol content and total acidity was less pronounced.</p>

Water stress during the post-harvest period affects new root formation but not starch concentration and content in Chardonnay grapevine (Vitis vinifera L.) perennial organs

“…The accumulation of carbohydrates in storage tissues depends on total photosynthesis and the partitioning of carbon among different plant organs (Howell 2001, Smith and. In temperate climate vines, several studies have demonstrated that the majority of the carbohydrate restoration in storage tissues takes place during the post-harvest period, which supports vine reserve recovery (Bennett et al 2005, Vaillant-Gaveau et al 2014. Although the rate of photosynthetic activity decreases in line with leaf senescence (Bertamini and Nedunchezhian 2003), functional leaves remain active and help the replenishment of reserves (Scholefield et al 1978, Loescher et al 1990.…”

Post-Harvest Regulated Deficit Irrigation in Chardonnay Did Not Reduce Yield but at Long-Term, It Could Affect Berry Composition

“…The two main flushes of root growth for wine grapes occur around bloom and after harvest [38,39]. As a result, post-harvest is a critical period for the restoration of carbohydrates in storage tissues to sustain the vegetative growth of vines in the following season, and to maintain yield levels [24,25]. Several studies have shown the links between the accumulation of carbohydrate reserves and yield parameters and berry weight [40][41][42]; this demonstrates that post-harvest defoliation and early leaf fall influence carbohydrate accumulation in vine roots.…”

“…After harvest, carbon assimilation is possible while vines still retain functional leaves and through until leaf fall. A loss of leaf area during this period, either due to water stress or defoliation, may therefore affect vegetative growth and yield in the following season [24,25]. To the best of our knowledge, there has so far been no study conducted with white wine grape cultivars that has evaluated the carry-over effects of adopting different RDI strategies during the post-harvest period into subsequent seasons.…”

Comparative epidemiology of grapevine and soybean rusts

“…The reduction in leaf area caused by early leaf fall may negatively reflect on the production quality and/or yield. Early defoliation can result in a lower soybean grain weight, uneven grape cluster maturation and reduced growth of grapevine branches (Yang et al, 1990;Mueller et al, 2009;Sikora et al, 2014;Vaillant-Gaveau et al, 2014). In annual crops, the effects of leaf area reduction are observed in the same season, while in perennial crops, the effects may be cumulative over the years.…”

“…The yield reduction is due to the low quantity of carbohydrates stored in the roots during the dormant period, and consequently, low supplies are available for plant development in the following season (Vaillant-Gaveau et al, 2014). Early defoliation is negatively correlated with yield in the same season for soybean, due to the low amount of carbohydrates translocated and stored in the grains (Mueller et al, 2009).…”