Responses to salinity of grapevine plants with split root systems

Abstract

SUMMARYGrape yield, shoot and root vigour and water use by grapevine plants with split root systems were investigated. Some plants had both root parts continuously irrigated either with fresh or with saline water. Some plants got a dual treatment; one portion got fresh water and the other saline water. The irrigation water of a third group was changed during the experiment from fresh to saline water or vice versa.Fruit yield and root and shoot viability were positively correlated with the actual water use. Water ascent along the stem of the grapevines was found to be sectorial. Most of the water was supplied by the freshwater roots. Only small quantities of water were supplied by salt-affected roots to their respective twigs.Changes in the water quality of the root medium induced a dual effect: {a) a fast response, caused by the direct change in the ambient water potential; and {b) a long-term response that developed over several weeks. The latter response was induced by the development of new roots, or by death of others, upon a change in the quality of the irrigation water.The commonly used grapevine plants of the Arava valley are negatively affected by NaCl already at concentrations below 100 mM. Under such conditions, shoot growth and fruit yield were seriously inhibited, even when one part only of the root system was exposed to saline water.

The response of the mangrove Avicennia marina to heterogeneous salinity measured using a split-root approach

“…Photosynthetic rates in the 35:65 plants were significantly lower than the 35:35 control plants, despite sharing a similar lowest salinity. A similar response was observed for pepper plants, where salinisation of only half the root system had a similar effect to the salinisation of the entire root zone (Lycoskoufis et al 2005) and grapevines, where the adverse effects of salinity were not overcome even if part of the root system was exposed to fresh water and the fresh water preferentially taken up (Shani et al 1993).…”

“…In this study we grew the mangrove A. marina in a split-root system (Shani et al 1993;Wiersum 1958) in order to firstly measure whether A. marina rapidly responds to changes in salinity to only part of its root zone. Using isotopically labelled water we determined whether preferential uptake of the different water sources offered to the seedlings occurred and we assessed how photosynthetic gas exchange is affected by short-term changes in salinity testing whether photosynthetic gas exchange was sensitive to the highest, lowest or mean salinity of the root zone.…”

Hydraulic properties and embolism in small-diameter roots of five temperate broad-leaved tree species with contrasting drought tolerance

“…The large root morphological and functional plasticity is, at least in part, a response to the high heterogeneity of moisture in soils, in particular in those exposed to periodic drought (Göttlein and Manderscheid 1998). Roots or root branches are acting as physiologically autonomous units (Shani et al 1993) that tend to optimize the cost/benefit ratio of root operation under variable water availabilities. In our study, all roots investigated for k s were sampled in the topsoil at 0-10 cm depth and thus, the differences in k s cannot be attributed to contrasting moisture regimes in different soil layers (see, for example, Pate et al 1995).…”

Assessing vulnerability and framing adaptive options of two Mediterranean wine growing regions facing climate change: Roussillon (France) and McLaren Vale (Australia)

“…However, the levels of water salinity were reported by interviewees as an important concern, especially those who use water from private bores. In contrast to rain water, irrigation water contains dissolved salts and deficit-irrigated vineyards are at risk from salinization, which limits grapevine growth, productivity and fruit quality (Downtown and Loveys, 1978;Shani et al, 1993). Thus, a major concern for irrigated vineyards in arid and semi-arid regions could be, rather than the increase in temperatures per se, increasing drought and salinity of soils due to higher evaporation coupled with declining water availability (Stevens and Walker, 2002;Keller, 2010).…”