Abstract

Germination of spinach (Spinacia oleracea L. var. grabra cv. Nobel) seeds was inhibited at a high temperature (35°C). Effects of KCN on the respiration of seeds incubated at 20 and 35°C were compared in order to investigate the mechanism of inhibition of seed germination by high temperature. Respiration of germinating seeds incubated at 20°C was inhibited about 50% by 5 mM. KCN solution, whereas it hardly inhibited the weak respiration of the seeds at 35°C. Germination of seeds was delayed by exogenous KCN. When the KCN solution was renewed daily, germination was completely inhibited. Pericarp removal promoted germination at 35°C, but atypical germination (cotyledons emerging earlier than a radicle) took up more than half of the total germination. The inhibitory action of KCN on the respiration of seeds was not altered by pericarp removal. A KCN addition, even at 20°C, elicited atypical germination in the pericarp-less seeds. These results show that cyanide-sensitive respiration is needed to induce typical spinach seed germination (root emergence), but is rendered inoperative by high temperatures thus bringing about poor germination and atypical germination.

This content is only available as a PDF.
You do not currently have access to this article.