SEED, FRUIT AND PLANT MORPHOLOGY OF WEEDS THAT OCCUR IN SOME CROPS IN BRAZIL

DORIS GROTH; MARIA REGELISA BOARETTO; ROSANA NEDEL DA SILVA

 

The study of the morphology of seeds and fruits is not well developed in Brazil. Precise identification of weed seeds is required in a seed analysis laboratory as well as in several other areas of seed technology. Morphological characteristics of seeds do not change appreciably in response to environmental factors and can be used as suitable criterian in taxonomical studies. Weeds with their dispersion characteristics were used for study since they are sources of productivity losses in crops, chiefly to seed yields. The main objective of this work was the characterization of the morphological features of the seeds that permit the taxonomical differenciation of genus and species. Such study intended to provide useful morphological informations to be handled by the seed technology specialists involved in breeding, crops inspection, milling plants, seed certification and marketing and seed analysis laboratories. Description, drawings and photographs of seeds and plants were carried out in the following species: Amaranthus deflexus L., Amaranthus lividus L., Amaranthus spinosus. L., Acanthospermum hispidum D.D., Xanthium spinosum L., Cassia hirsuta L., Cassia occidentalis L. and Cassia tora L. Description was based on the morphologica! characteristics such as shape, size and other particular features of the roots, shoot, leaves, flowers, fruits and seeds. Regarding the seeds, the followings descriptions characteristics were considered: shape, size, surface (color, firmness, apendages, thickness, structure, etc), hilum (color, shape, positon and tiltness), the micropile, the rafe, storage tissues, and the embryo (absolute and relative sizes, shape of the cotyledons, etc).



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