Tolerance to Lime - Induced Chlorosis and Drought in Grapevine Rootstocks - Abiotic Stress: Plant Responses and Applications in Agriculture - page 278

to environmental conditions, e.g. their tolerance to lime, low soil pH, soil humidity, salts etc.,
is very important.
Nowadays, grapevine plants are more and more influenced by various kinds of environmental
stress. The most important kinds of abiotic stress are the following: extreme temperatures or
too high (or too low) irradiation, water logging, drought, lack of minerals in soil (their
deficiency) and too high salinity of soil (Koyro et al., 2012). Stress can be defined as an
environmental factor that shows a negative effect on the living organism (Levitt, 1980).
This review tries to summarise data about the adaptation of rootstocks to soil (pedological)
conditions, viz. their resistance to lime-induced chlorosis and drought. Regarding the global
warming, these properties of rootstocks are very important also under conditions of the Central
European viticulture.
2. Root system of grapevine plants
The most important functions of the grapevine root system involve anchoring of plants in soil,
storage of reserve substances, uptake and conduction of water and dissolved nutrients within
the plant and synthesis of growth hormones. The root system consisted not only of older,
lignified roots but also of a great number of new ones that are used above all for the uptake of
nutrients. Regarding their diameter, roots can be divided into two groups. Thick roots (with
the diameter above 2 mm) represent a great proportion of root biomass. They create the
“architecture“ of the root system, enable the transport of water and nutrients and fulfil the
function of a reserve organ. Fine roots (with the diameter below 2 mm) enable above all the
uptake of water and nutrients. These are above all root hairs that develop on thicker roots.
Root tips consist of root caps and apical meristem. This apical meristem assures growth and
development of roots. Root growth takes place in the elongation zone which is approximately
two milimeter long. Root tips are also the place of synthesis of plant hormones (gibberelins
and cytokinines). These growth hormones are transported via conductive tissues into the
aboveground parts of the plant and participate in processes controlling the balance between
roots and tops, initiation of flowering, and growth and development of berries. Cell division
(and, thus, the growth of roots) is controlled by auxins that are transported from tops of annual
shoots into roots via phloem. The elongation growth is influenced by gibberellins that are
synthesised in roots. Root hairs are localised behind the elongation zone of roots and assure
the uptake of water and nutrients. It is capable to release organic compounds into the soil and
to participate in propagation and development of microflora existing in the root zone
(Pavloušek, 2011a).
The distribution of roots in soil is influenced by soil and environmental factors, e.g. tempera‐
ture, degree of aeration, texture, availability of water and nutrients, pH value and frequency
and depth of tillage operations (Richards, 1983, Morlat & Jaquet, 1993).
The root system of grapevine plants is mostly created by the root system of rootstocks. The
root system of grapevine rootstocks enables the uptake of water and nutrients from greater