Influence of abiotic stresses on seed germination, quality and s

INFLUENCE OF ABIOTIC STRESSES ON SEED GERMINATION, QUALITY AND SEED PRODUCTION

This study describes the results of experiments with nine winter wheat cultivars (Astella, Estica, Ilona, Regina, Samanta, Šárka, Vlada, Vlasta, Zdar). From the agronomic point of view "seed provenance" i. e. influence of individual (and of combinations) of different abiotic stresses has influence on the seed traits and on the first phases of plant development and the yield formation. Responses of winter wheat cultivars to different abiotic stresses and their combinations were analysed in laboratory conditions, pot experiments and field experiments. Plant treatments during experiments were: standard level of nutrients, low level of nutrients, drought, high temperature, salinity, waterlogging. Strong influence of stress conditions on 25 grain traits was obtained. There was measurable influence of abiotic stresses on a degree of contamination of seeds by spores of pathogenic fungi. There is a large influence of "provenance" on the root different traits and on the nutrient uptake. Also large changes are measurable especially at root morphology. Seed provenance had very strong effect not only on the first phase of plant development, but also on yield formation. The order of importance of individual traits of the seed and root for plant production depends on genotype and on the environmental conditions (type of stress). There are lot of possibilities of utilisation genetic resources for shortage of influence of stresses i.e. from agronomic point of view shortage of influence of negative environmental conditions. A wider genetic diversity of crops and cultivars also contributes to more stable production and balanced agroecosystem. Especially recent cultivars expresses higher vigour of seeds. On the other hand old cultivars are more tolerant to drought and high temperature stresses, their roots also penetrate deeper roto the soil. It is also possible to use presented results in plant breeding, e.g. to use old cultivars as a source of stress tolerance.

Water stress reaction dependent on seed reserves altered by abiotic stress was studied at above mentioned nine cultivars. Differences in osmotic potential between some genotypes Regina 0.25 MPa, Zdar 0.19 MPa, Astella 0.18 MPa were detected. Seedlings of these genotypes, grown under the stress conditions (moisture deficit) had higher osmotic potential than those, grown under well - watered conditions. No differences were detected in osmotic potential between other genotypes (e.g. Samanta 0.04 MPa). Water content per dry weight of 2 cm coleoptile segments was not influenced by seed origin. The seedlings grown under stress conditions had lower water content of 2 cm coleoptile segments (on average 9.4 g water/ g dry matter) than the seedlings grown under well - watered conditions (on average 10.4 g water/ g dry matter). Osmotic potential of 5-days old winter wheat seedlings were influenced by following three factors: seed origin, seed size and moisture deficit, with 93 % probability according to ANOVA analysis.

Autor: L. Bláha, V. Novák, J. Zámečník, F. Hnilička, M. Ottová

Zdroj: COST 828 Action. Seed Science in the field of genetically controlled stress physiology

(Abstracts), INRA, Toulouse Centre, France, 11 - 14 November, 1998, p. 14, 1998