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Universidad Nacional de Córdoba (2015)

Respuestas morfo-fisiológicas de la germinación de Vicia dasycarpa Ten. cv. Tolse F.C.A. en condiciones de estrés hídrico y salino

Perissé, Patricia

Titre : Respuestas morfo-fisiológicas de la germinación de Vicia dasycarpa Ten. cv. Tolse F.C.A. en condiciones de estrés hídrico y salino

Auteur : Perissé, Patricia

Université de soutenance : Universidad Nacional de Córdoba

Grade : Doctor en Ciencias Agropecuarias 2015

Résumé
The movement of livestock into marginal areas in Argentina has led the forage species to environmental heterogeneity. This requires the proper use of species and varieties in these environments. Vicia dasycarpa Ten. cv. Tolse F.C.A. stands out as forage of autumnwinter- spring cycle that provides quality dry matter. The aim was to study the morphophysiological responses of germinating V. dasycarpa Ten. cv. Tolse F.C.A. under water and salt stress. The morphological characteristics of the seeds were studied in relation to the area of imbibition water entry. Tests were conducted to determine the percentage of germination under different treatments : control 0 MPa ; PEG-0.3 ; -0.6 ; -0.8 ; -1 and -1.2 MPa ; NaCl -0.3 ; -0.6 ; -0.8 ; -1 and -1.2 MPa. The conventional methodology was used to perform the morphological and anatomical studies -stereoscopic microscopy, optical microscopy (OM), scanning elect ron microscopy (SEM)- and for the ul t rast ructure -transmission electron microscopy (TEM). The results indicate that the seed has a linear hilum, a deltoid micropyle ; the seed coat is dark reddish brown, with black streaks and the pattern of ornamentation is papillose. It was confirmed the presence of a radicle pocket and the presence of two pairs of cotyledonal areoles were identified. It was established that the entry of water during imbibition starts at the lens -having cracks- and moves in the sagittal plane. The germination is crypto-hypogeal and the seedling has three fertile cataphylls (with its developed buds). Under conditions of water and salt stress, with a water potential equivalent to -0.6 MPa, it was overcame the 80% germination. For the hydrotime model the base water potential to reach the 50% germination was -0.9 MPa for PEG and -1.4 MPa for ClNa. The morpho-physiological studies showed a decrease in growth of both the root and caulinar system in all treatments. In the caulinar system the axillary buds developed are a recovery strategy to stress. The anatomical structure of the root was affected by water and salt stress. Cellular plasmolysis was manifested in the rhizodermis and cortex ; in the most severe water stress treatments endodermis collapsed. V. dasycarpa cv. Tolse F.C.A. can be considered a promising forage for growing under soils with water deficiency or salinity problems.

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Page publiée le 19 juillet 2017