Características físicas, morfológicas e fisiológicas de sementes de Flemingia macrophylla (Willd.) Alston

Abstract

The Flemingia macrophylla (Willd.) Alston is a leguminous species with low anthropogenic pressure that is being considered with potential use in different areas like medicinal plants, ornamental and green manure, soil cover during the offseason and recovery of degraded areas. Is common in legume seed coats are impermeable to water absorption. A study of physical and morphological characteristics of the species F. macrophylla is necessary and the current publication of Rules for Seed Analysis does not include information about this species. It is also necessary to research specific methodologies for overcoming seed dormancy and factors such as temperature and substrate. It were obtained three seed lots, one lot (harvested in July / August 2007), lot 2 (harvested in July / August 2008) and Lot 3 (harvested in July / August 2009) in EMBRAPA - Agrobiologia and UFRRJ, Seropédica RJ. From the selected seed pods were removed and after the separation of seed screens, we determined the mass of thousand seeds (MMS), mass of hectolitre, number of seeds per gram, and measures of length and width (mm). In anatomical characterization seeds were sectioned longitudinally and transversely with microtome to visualize the external and internal seed morphology with Binocular Stereoscopic Microscope by WILD M5 model. Stages of germination, seedling morphology and structure were evaluated. The moisture content of seeds ranged from 9.46 to 12.10 %, mass of thousand seeds ranged from 18.11 to 19.28 g, the hectolitre mass ranged from 72.23 to 74.39 kg and the number of seeds / 52 g to 55 seeds. The seed coat is formed by the layer of palisade cells, externally glossy color is black or brown spots. The seeds of Flemingia have two cotyledons with embryo axis and the absence of endosperm, seedling epicotyls show featuring the germination hypogeal. Later treatments were applied to scarification: 1. Without scarification, 2. Soaking for 24 h at 25°C shaken at 300 RPM in distilled water, 3. Soaking for 48 h at 25°C shaken at 300 RPM in distilled water, 4. Immersion in water for 20 min. at 90°C, 5. Immersion in water at 90°C and rest for 24 h, 6. Immersion in water for 10 min. at 90°C, 7. Immersion for 5 min. in hydrated ethyl alcohol 8. Immersion for 10 min. in concentrated sulfuric acid, 9. Immersion for 20 min. in c.s.a., 10. Scarification for 45 min. in sandpaper N° 100, under rotation of 300 RPM. It was determined the moisture content periodically up to 48 h. The increase in seed moisture content is more uniform than when used scarified in c.s.a., reaching 57.53 % after 48 h. Depending on the results obtained, we evaluated the methods 1, 4, 9 and 10 at temperatures of 20°C, 25°C and 30°C constant and 20-30°C alternating. The most efficient method of scarification was associated with c.s.a. at temperatures of 25, 30°C Constant and 20-30°C alternating. In another experiment were evaluated the germination and seed vigor in relation to substrates roll of paper (RP), paper (SP) and sand (EA) at temperatures of 30°C and 35°C constant and 20-30°C alternating. There's a higher germination and vigor using the sand substrate at temperatures alternating between 20-30°C and constant 30°C and 35°C. The tetrazolium test reveals a rapid test for use in estimating Flemingia seed germination.