Chemistry Reference
In-Depth Information
switches on, for example LEA proteins - dehydrins [32]. Generally scientists agree these
proteins play important role in tolerance to water stress. Their protective function consists in
stabilization of membrane structures [31, 84]. Angelovici [3] discussed gene expression and
metabolic activation during desiccation of seed and their influence to the desiccation
tolerance, dormancy competence and successful germination of the dry seeds. Together with
genetically conditioned production of osmoprotective substances (as proline at rape tolerant
to salinity [70] the maternal effect applies role in adaptation to environmental conditions too
[46, 47, 88]. Dyer et al. [40] confirm the seed adaptation of some invasive species to adverse
conditions in germination time on the mother plant in time of their maturation. They think
that transgeneration plasticity (TGP) of seeds is the result only just seed adaptation on
stressed plants. TGP can explain phenotypic move in adaptability of plants to worse
environmental conditions and influence by this way more easy spread of species in
environment.
The participation of environmental conditions on development of viable seed is generally
taken to consideration; this influence can be even significant. When the stress conditions are
continuous, developing seed can be damaged and on macroscopic level it means higher
occurrence of less vigorous or even non-germinated seeds. In slightly adverse conditions
protective compounds accumulate in seed and stay stored inside after desiccation. It has
also been demonstrated that in seed stored rather than de-novo synthesized mRNAs play
key roles during germination
The influence of seed on plant individual is formed in time of seed development on mother
plant. Seed quality affects the germination process, which can be modified strongly by
environmental conditions and next development of plant. The seeds germination is a
complex physiological process comprising many metabolic pathways [66] with the goal to
originate new plant as the next generation of plant species). Germination starts with uptake
of water to the dry seed by imbibition, followed by metabolic changes in seed and ends with
rupture of covering layers and emergence of radical protrusion. Figure 4 shows the example
of the seed provenance on the root system of juvenile plants.
Ability of seeds to germinate in adverse environmental conditions is expressed as seed vigor
can be explained as difference between germination percentages analyzed at optimal
conditions by laboratory tests and between percentages of seedling emergence in field
conditions (field emergence). There is lot of reasons for this difference (diseases, soil
conditions, water content in soil, variability of temperature in the soil, etc.).
The influence of the seed provenance together with cultivar is very important. For example,
the obtained results from the experiment with the organic and conventional seeds (four
different provenances) of various spring cereal cultivars (bread and emmer wheat,
Triticum
aestivum
L. and
T. dicoccum
Schrank, barley,
Hordeum vulgare
L. and oat,
Avena sativa
L.)
confirmed importance of the cultivar and the seed provenance for the seed quality especially
for the germination and efficiency of water utilization during this development phase. This
is very important factor because of seed biological quality is one of basic factors, which has
influence on the growth and development of the filial generation, especially in drought
