Anatomía de la semilla de Cupania dentata (Sapindaceae), con énfasis en la semilla madura

Abstract

CUPANIA DENTATA MOC. ET SESSE EX D.C. (SAPINDACEAE) IS A SPECIES USED MAINLY AS FIREWOOD. SEED STRUCTURE WAS STUDIED AT AN EARLY STAGE OF DEVELOPMENT, 12 WEEKS AFTER ANTHESIS AND AT MATURE STAGE, 32 WEEKS AFTER ANTHESIS, BY LIGHT MICROSCOPY. GENERAL STAINING WITH SAFRANIN "O" AND FAST GREEN FCF, AND SPECIFIC STAININGS FOR LIPIDS, LIGNIN, STARCH AND TANNINS DETECTION WERE ALSO PERFORMED. THE SEED IS BITEGMIC, CAMPYLOTROPOUS WITH A NUCELLAR CURVATURE OF 103O. THE SEED DEVELOPS A PACHYCHALAZA WHICH COMPRISES APPROXIMATELY 43% OF THE MATURE SEED COAT AREA. THE YOUNG EXOTESTA WAS COMPOSED OF A PALISADE LAYER WITH THICK CELL WALLS RICH IN TANNINS, WHICH AT THE MATURE STAGE, BECAME THICKER AND LIGNIFIED. THE YOUNG MESOTESTA SHOWED FROM 10 TO 26 PARENCHYMA LAYERS WITH CONDENSED TANNINS IN THEIR LUMENS. BOTH IN YOUNG AND MATURE MESOTESTA TISSUE, NUMEROUS LIPIDIC IDOBLASTS, EVENLY SPREAD, WERE FOUND. THE YOUNG INNER INTEGUMENT SHOWED FROM 3 TO 4 LAYERS OF PARENCHYMA, WHICH AT MATURE STAGE, APPEARED COMPLETELY COMPRESSED AND COLLAPSED. THE ARIL OF THE YOUNG SEED IS PALE, IDENTIFIED AS N10 A40 M00 COLOUR, AT THIS STAGE OF DEVELOPMENT THE ARIL, RICH IN LIPIDIC IDIOBLASTS, COVERED APPROXIMATELY 70% OF THE SEED VOLUME. AT THE MATURE STAGE. THE ARIL ONLY COVERS UP TO 50% OF THE SEED VOLUME AND IT BECOMES WAXY AND YELLOW N10 A80 M30 , PENETRATED BY A LARGE POPULATION OF LIPIDIC IDIOBLASTS. THE ARIL MAKES AN ARILOSTOME AT THE MICROPILAR REGION. THE MATURE SEED HAS NO ENDOSPERM BUT THE EMBRYO, RICH IN STARCH GRAINS, CONSTITUTES THE MAIN STORAGE TISSUE OF THE MATURE SEED.