Chemistry Reference
In-Depth Information
considerable economic costs connected with maintenance of genetic resources. This situation
can lead even to loss of genetic resources.
Consequent changes during long term storage consist from: increasing concentration of free
radicals, which are formed in time of long-term seed storage, damaging membrane lipids,
inactivation of enzymes, damaging storage proteins and DNA. This process resulted to
lower seed quality (low vigor) or even total loss of germination. Deterioration of the seeds
during storage is irreversible phenomenon, natural for living organisms. Aged seeds
influence optimal root growth (angle of root growth in the soil, depth penetration, tillering).
Roots quality influences water utilization in plants
with different level by different
cultivars in different environmental conditions and by this way drought tolerance during
vegetation period and through the new filial seed generation germination and grow of
young plants.
The water availability and efficiency of water utilization in time of germination is one of the
basic factors influencing field emergence rate. Water uptake is the first step for enzymes
activation, and shortly, for successful germination. The large variability in water use
efficiency of seeds of different species and cultivars exist.
2. Seed and root phylogeny - general overview
The seeds, roots and their properties are the result of the phylogenic development under
stress pressure, especially the influence of dry conditions in time of plant colonization of the
Earth.
The seed phylogeny
reflects very interesting historical transition for photosynthetic
organisms. The seed history consists of four main steps: the development of seed
morphological structures, anatomy of seeds; the development of dormancy and the
evolution of seed size (mass) [65, 66]
Seeds were developed over a period of approximately 300 million years of phylogeny for
three main reasons [11, 14, 16, 63]
1.
increase of species distribution area
2.
preserve species for adverse conditions
3.
enable efficient reproduction of species
The roots
have from the paleontological view the first predecessors in -rhizoids- unicellular
“fibres“. [16]
So far, the oldest fossils of these plant organs - real roots came from the period 396 million
years ago. As evidence for the findings of the first roots are two plants Rhynia and Sigillaria
from the late Devonian period, where paleontological analysis revealed the depth of the
roots with length no more than one meter. Plant roots are most sensitive part of plant body.
The morphological and physiological root traits respond much more sensitive to the
external environment than the aboveground parts of plants. Roots have a large share in the
creation of soil, impact on the composition of the micro flora in the formation of ground,
humus, the production of carbon dioxide, i.e. the composition of the atmosphere.
