Tolerance to Lime - Induced Chlorosis and Drought in Grapevine Rootstocks - Abiotic Stress: Plant Responses and Applications in Agriculture - page 289

The grapevine ( Vitis vinifera ) has different physiological and morphological mechanisms
enabling it to maintain growth and production also under conditons of water deficiency
(Kondouras et al., 2008).
In Europe, varieties of Vitis vinifera are traditionally cultivated in non-irrigated regions. Yield
of grapes as well as the quality of berries is therefore dependent on the adaptability of
grapevine plants to drought. A good understanding and control of the water regime of plants
as well as influencing their tolerance to drought stress on the base of application our knowledge
of plant physiology and molecular biology may significantly increase not only productivity of
plants but also quality of environmental conditions.
In grapevine, water supply of plants plays an important role in processes of plant growth and
formation of berries. A limited supply of water reduces not only the growth of annual shoots
but also the weight of berries and the final yield of grapes. A marked lack of water may result
in reduced yields and an impaired quality of grapes. This means that in the course of the
growing season the occurrence of stress induced by water deficit shows a significant effect on
physiological functions of grapevine plants. Although the grapevine ( Vitis vinifera ) is a species
showing a very good tolerance to drought, a severe stress may sometimes markedly influence
qualitative properties and parameters of grapes. When using plant material adapted to
drought conditions, it is possible to avoid losses caused by a severe water stress (Van Leeuwen
et al ., 2009).
Selection and breeding of grapevine rootstocks and varieties with a higher water-use efficiency
represents a possibility how to adapt viticultural production to current climatic changes
(Vandeleur et al., 2009, Flexas et al., 2010).
4.1. Properties influencing the tolerance of grapevine plants to drought
In the course of phylogenesis the grapevine ( Vitis vinifera L.) plants have developed various
physiological and morphological mechanisms, which enable them to maintain their growth
and fertility even under conditions of a limited availability of water.
Although grapevine ( Vitis vinifera L.) is considered to be a species adapted to drought
stress, the combined effect of high irradiation, high temperatures and low atmospheric
water pressure tension would presumably act as major constraint for the leaf photosyn‐
thesis, particularly under conditions of severe soil water deficits usually encountered by
this crop (Flexas et al ., 1998).
Physiological responses of plants to water deficit are linked to a condition of recognition of
stress by the root system, turgor changes and water potential and consequently stomatal
conductance, internal CO 2 concentration and photosynthetic activity decrease. From a
molecular perspective, several genes expressed under stress conditions are activated, such as
genes linked to the biosynthesis of abscisic acid and synthesis of specific proteins (Chavaria &
Pessoa Dos Santos, 2012). This means that in plants the water stress is manifested by many
different mechanisms.