Ultrastructure of Solid Matrix-Primed Endospermic and Nonendospermic Seeds

Abstract

It was shown that solid matrix priming (SMP) with Micro-Cel E of carrot (endospermic) and cucumber (nonendospermic) seeds improved their germination performance by shortening the mean germination time, lowering the spread and increasing the tolerance to low temperatures. The cytological studies performed on these seeds allowed us to conclude that developmental advancement in seed metabolism occurred during the studied period of SMP. So far, other ultrastructural data concerning cellular events taking place during SMP are not available. It was found that an advancement in the catabolic phase of germination sensu stricto was taking place in the radicles of embryos of both types of seeds, where degradation of storage protein and lipid bodies, followed by starch accumulation was stated. In the endosperm tissue of the carrot seed, the catabolic changes were restricted to the part enclosing the radicle, where degradation (only partial) of storage protein bodies and complete degradation of storage cell wall components were noted. In contrast, the data showed that the breakdown of the storage materials in the endosperm (weakening of endosperm) represented a secondary effect of SMP, which was probably controlled and stimulated by the metabolically advanced embryo.