Morfofisiologia, restrição hídrica e armazenamento na germinação de sementes e, enraizamento de miniestacas de Diospyros lasiocalyx Mart. B. Walln

Abstract

The species Diospyros lasiocalyx belonging to the Ebenaceae family is adapted to soils with nutritional deficiency and has potential in the recovery of degraded ecosystems. The objective of the work was to obtain information about the biometric characteristics of fruits and seeds, the influence of origin, seed size, fruit maturation stage; the effects of water restriction, storage on seed quality and seedling vigor, in vitro germination and rooting potential of minicuttings. Ripe fruits were collected from breeders in the reproductive stage in the rural areas of Alta Floresta/MT and Nobres/MT. The dimensions and mass of fruits and seeds taken at random from each municipality were evaluated. The seeds were distributed into classes and the water content of the seeds separated by origin, size, at different stages of fruit maturation and under water restriction conditions was determined. The effect of the plant regulator gibberellic acid at concentrations of 50 and 100 mg L-1 , of the conditioner polyethylene glycol 6.000 on the water potential of -0,5 Mpa, on water restriction and at times of 0, 12, 24, 48 and 96 hours. For storage for 360 days, the seeds were dried at water contents of 8,10, 12 and 32%. In vitro germination was carried out from dry seeds at 12 and 32% under the conditions: in the presence and absence of light immersed in 2,5% hypochlorite for 0, 10 and 20 minutes. The minicuttings were obtained from a minigarden and treated with talc containing IBA at concentrations of 0, 1.000, 2.000 and 3.000 mg L -1 . The biometric characters of D. lasiocalyx fruits and seeds are homogeneous. The average time, germination speed index, dry mass of the shoot and root in the paper substrate differed between the two origins, with the best averages for Alta Floresta/MT. The seeds had an initial water content of 22,55% and the PEG solutions added GA3 at concentrations of 50 and 100 mg L-1 . D. lasiocalyx seeds had an initial water content of 41%, tolerate desiccation at 8% and can be stored for 360 days. Sodium hypochlorite was not efficient in controlling microorganisms, reducing germination by immersion in 10 and 20 minutes. The rooting percentage was 93,2% in minicuttings treated with 3.000 mg L-1 of IBA. It is recommended to collect mature and pre-ripe seeds as they have greater germination potential. Seeds soaked for 12 hours in gibberellin at a concentration of 50 mg L-1 reached maximum germination capacity. The formation of normal seedlings is reduced with the use of PEG at a water potential of -0,5 MPa. Seed storage for 360 days at a water content of 12% is viable without compromising the viability and vigor of the seedlings. The seeds of D. lasiocalyx showed high in vitro germination (>90%) and the minicuttings rooted without and with the use of IBA application.