Two-dimensional gel electrophoretic protein profile analysis during seed development of Ocotea catharinensis: a recalcitrant seed species

The aim of the present work was to characterize changes in the protein profile throughout seed development in O. catharinensis, a recalcitrant species, by two-dimensional gel electrophoresis. Protein extraction was undertaken by using a thiourea/urea buffer, followed by a precipitation step with 10% TCA. Comparative analysis during seed development showed that a large number of proteins were exclusively detected in each developmental stage. The cotyledonary stage, which represents the transition phase between embryogenesis and the beginning of metabolism related to maturation, presents the highest number of stage-specific spots. Protein identification, through MS/MS analysis, resulted in the identification of proteins mainly related to oxidative metabolism and storage synthesis. These findings contribute to a better understanding of protein metabolism during seed development in recalcitrant seeds, besides providing information on established markers that could be useful in defining and improving somatic embryogenesis protocols, besides monitoring the development of somatic embryos in this species.

Massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae): efeitos na emergência e desenvolvimento de suas plântulas no sol e na sombra

The aim of this study was to evaluate the effect of Tecoma stans L. Juss. ex Kunth seeds mass on initial emergence, growth and, seedling development under different light conditions. The seeds were separated in four mass classes and sowed in four replicates of 24 seeds for each class, under full sun and canopy shade. Under sun environment was observed a greater percentage of emergence. Heavy seeds presented the greater percentage of emergence under both environments, but a greater rate was observed under canopy shade. One month after the start of experiments, the seedlings at the shade environment presented 100% of mortality. The growth and development seedlings under full sun were noticed for five months. In this period, only in the first three months was possible to observe the effects of Tecoma stans seeds mass on capacity of seedlings to acquire dry mass. The seedlings biomass partitions were similar among the tested mass class. The seedlings of smaller mass tended to a high specific leaf area in relation to the seedlings from large seeds, mainly in the first three months, resulting in a great acquisition of dry mass by these seedlings. In the fourth month, the specific leaf area did not present any tendency. Because the biggest seeds to give rise seedlings with best initial development than smallest seeds can be considered as species reproductive strategy. To produce seeds of different sizes also can be considered as way of species to spread in many microhabitats.