An Analysis of Seed Development inPisum sativum

Abstract

The influence of abscisic acid (ABA) on the precocious germination and storage protein production of pea seeds has been examined using embryo and pod culture. The precocious germination of embryos in culture could not be inhibited fully by ABA on a permissive medium (2% sucrose) even at 0.1 mol m⁻³. However, increasing the sucrose concentration to 5% caused near complete inhibition when ABA was added to the medium. Embryos of different weights cultured on a high osmoticum (mannitol-containing medium), equivalent to 10% sucrose, did not show any consistent difference in ABA content. When fluridone was added to a non-permissive culture medium, no decrease in ABA content of the embryos could be observed and no precocious germination was induced. In contrast, fluridone was able to prevent the accumulation of ABA in seeds present in pods cultured in its presence from an early stage of development. These seeds, however, grew normally and reached maturity, did not germinate precociously in vivo, were desiccation tolerant and still produced storage protein message whether or not ABA was included in the culture medium. It does not appear, therefore, that ABA regulates normal development or storage protein synthesis in pea embryos.