Soil temperature moderates grapevine carbohydrate reserves after bud break and conditions fruit set responses to photoassimilatory stress

Abstract

In cultivated grapevines (Vitis vinifera L.), suboptimal photoassimilatory conditions during flowering can lead to inflorescence necrosis and shedding of flowers and young ovaries and, consequently, poor fruit set. However, before this study it was not known whether carbohydrate reserves augment fruit set when concurrent photoassimilation is limited. Carbohydrate reserves are most abundant in grapevine roots and soil temperature moderates their mobilisation. Accordingly, we grew potted Chardonnay grapevines in soil at 15 C (cool) or 26 C (warm) from bud break to the onset of flowering to manipulate root carbohydrate reserve status. Then to induce photoassimilatory responses we subjected the plants to low (94 mmol mol -1 ) CO 2 or ambient (336 mmol mol -1 ) CO 2 atmospheres during fruit setting. Analyses of photoassimilation and biomass and carbohydrate reserve distribution confirmed that fruit set was limited by concurrent photoassimilation. Furthermore, the availability of current photoassimilates for inflorescence development and fruit set was conditioned by the simultaneous demands for shoot and root growth, as well as the restoration of root carbohydrate reserves. Results indicate that great seasonal variability in grapevine fruit set is a likely response of cultivated grapevines to photoassimilatory stresses, such as shading, defoliation and air temperature and to variations in carbohydrate reserve status before flowering.

Elevated root-zone temperature hastens vegetative and reproductive development in Shiraz grapevines

“…Starch content was determined on a 20 mg of sample using the method described in Rogiers et al (2011b). At each time point, six plants per treatment were removed from their containers and divided into the following components: roots, belowground trunk, above-ground trunk, cordons, spurs, shoots, leaves, infructescence rachis and berries.…”

“…The ovaries undergo fertilisation, but the process is highly variable with successful fruit set ranging anywhere from 15 to 60% (May 2004). More specifically, it has been shown that competition for photoassimilates between simultaneous root growth, shoot growth and carbohydrate reserve restoration all affect fruit set in Chardonnay (Rogiers et al 2011b). More specifically, it has been shown that competition for photoassimilates between simultaneous root growth, shoot growth and carbohydrate reserve restoration all affect fruit set in Chardonnay (Rogiers et al 2011b).…”

“…Because root-zone warming can hasten root reserve mobilisation, canopy development and carbon assimilation (Field et al 2009, Rogiers et al 2011b, this may alter source-sink relations within the plant later in the season with consequences for berry growth and ripening as well as for final fruit size and composition. Because root-zone warming can hasten root reserve mobilisation, canopy development and carbon assimilation (Field et al 2009, Rogiers et al 2011b, this may alter source-sink relations within the plant later in the season with consequences for berry growth and ripening as well as for final fruit size and composition.…”

Modern viticulture in southern Europe: Vulnerabilities and strategies for adaptation to water scarcity

“…drought) is crucial to understand plant responses to the environment and to improve plant water relations and WUE (Roelfsema and Kollist, 2013;Tsegay et al, 2014). Besides, stomatal regulation in grapevine varies with the genotype (Costa et al, 2012;Tomás et al, 2014a) and identically, we find large intra-specific variability for intrinsic WUE (Bota et al, 2001;Gaudillère et al, 2002;Koundouras et al, 2008;Rogiers et al, 2011;Tomás et al, 2012).Improved WUE can result in water savings at both plant and crop levels, but scaling-up from single leaves to crop is not a straightforward process . In fact, previous research showed that improvements in leaf-level WUE may not always translate into higher crop WUE or higher yield (Condon et al, 2004).…”

Nocturnal and daytime stomatal conductance respond to root-zone temperature in ‘Shiraz’ grapevines

“…Root growth (Larson, 1970; Kasper and Bland, 1992), water uptake (Wan et al , 1999), nutrient uptake and availability (MacDonald et al , 1995; BassiriRad, 2000; Melillo et al , 2002; Pregitzer and King, 2005) and signal transduction (Zhang et al , 2008; Field et al , 2009) are all influenced by the temperature of the soil. These processes affect above-ground growth (Lopushinsky and Kaufmann, 1984; Dawes et al , 2011; Rogiers et al , 2011 b ) and productivity (He et al , 2001). As a result, analogous to air temperature, soil temperature can limit the geographical distribution of plants and crops (Fosaa et al , 2004).…”