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The effect was studied of sunlight and far‐red (FR) light during seed development, on seed quality and germination of Sicyos deppei G. Don. Seeds exposed to FR during development were lighter in colour and their weight, size and water content were significantly lower. Less than 10% of non‐scarified freshly harvested seeds germinated. Scarified, freshly harvested seeds developed under sunlight had a partially negative photoblastic response; both red (R) and FR light inhibited germination. The highest and fastest germination occurred in darkness, probably due to the effect of the high photon flux densities on the phytochrome during seed development. Scarified seeds ripened under FR light, germinated well in FR light and in darkness, but R light inhibited germination. After 6 months of storage, the permeability of S. deppei seeds increased, the partially negative photoblastic response was lost and germination of scarified seeds increased. Specifically, in seeds developed under FR, germination in darkness was faster than for the other light treatments, but slow in darkness for seeds developed under sunlight. The physiological and morphological heteroblastic responses in S. deppei probably extend its seed germination and seedling recruitment periods.

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Annonaceous acetogenins (ACGs) are molecules with carbon numbers C35-C37, usually with tetrahydrofuran and tetrahydropyran rings and one terminal γ-lactone (usually α,β-unsaturated), in a large aliphatic chain that is varyingly hydroxylated, acetoxylated or ketonized. ACGs have ecological functions as insecticides and are pharmacologically promising due to their cytotoxic and antitumoral properties. They are found in the seeds, leaves, roots, flowers and fruits of annonaceous plants and can be detected during isolation via thin-layer chromatography using Kedde's reagent, which reacts with the unsaturated lactone. This chapter describes the location in situ of ACGs in fresh sections of annonaceous seeds using Kedde's reagent.The acetogenins are located in the idioblasts, in the endosperm and in the embryonic axis during differentiation. This method can aid in the detection of ACGs with a terminal unsaturated γ-lactone in organs and tissues.

Resumen. Se determinaron las características y calidad de las semi llas de Ch. pentadactylon, de dos localidades en Guerrero y Oaxaca, su germinación bajo los factores de escarificación, temperatura y luz y la viabilidad d e semillas de Gu errero almacenadas 6 meses a 5º C. Las semillas resultaron ortodoxas y con latencia por cubie rta sem in al impermeable. Las semillas de Guerrero presentaron mayor peso, longitud y contenido de humedad respecto a las de Oaxaca , pero las semi llas escarificadas de Oaxaca germinaron con mayor porcen taje. La germinación de sem illas escarificadas de ambos siti os fue mejor en temperatura flu ctuante y se inhibió bajo rojo lej ano . No hu bo diferencias en la capacidad germinativa bajo obscuridad, luz roja y b lanca. Una fracción d e la población de semi llas podría permanecer latente en bajas relaciones de rojo:rojo lej a no transmitidas por la hojarasca. Las diferencias entre poblaciones pudieron deberse a un efecto materno inducido por temperatura y la humedad de sus localidad es. Palabras clave: germinación, almacenamiento, fotoblastismo, semi llas ortodoxas, temperatura de germ in ación. Abstract. Seed quality and seed germination with scarificatio n and n on scarification and variab le temperature and light were determined in Ch. pentadactylon seeds form two pladces of Guerrero and Oaxaca. Also seed viability was determined in seeds from Guerrero stored 6 months at 5º C. Seeds showed to be orthodox a nd dorman t dueto an impervious seed coat. The seeds from Guerrero had higher weight, length and water content tha n those from Oaxaca, however the scarified seeds from Oaxaca reached a higher germination percentages. Germination of scarified seeds of the two popu lations was enhanced by alternated temperatures and in hibite d by far red light. Germ in ation under darkness, red light and wh ite light did not differ significan tly. In soil sorne seeds could be dormant under a low ratio red:far red light transmitted by litter. The differences between the two populations might be due to a maternal effect induced by weather conditions in their geographic localiti es.