AP BIOLOGY

Detailed explanation-1: -Among the different plant hormones, abscisic acid (ABA ) and gibberellin (GA) are considered as major players in the regulation of dormancy and germination; ABA regulates dormancy induction and maintenance positively while GA promotes seed germination (Kucera et al., 2005; Finkelstein et al., 2008).

Detailed explanation-2: -Bioactive gibberellins (GAs) promote seed germination in a number of plant species. In dicots, such as tomato and Arabidopsis, de novo GA biosynthesis after seed imbibition is essential for germination. Light is a crucial environmental cue determining seed germination in some species.

Detailed explanation-3: -Gibberellins (GAs) break seed dormancy and promote germination (1, 2), and several other hormones, including brassinosteroids, ethylene, and cytokinin, have also been shown to promote seed germination (3, 4). However, abscisic acid (ABA) is the only hormone known to induce and maintain seed dormancy.

Detailed explanation-4: -GA stimulates the seed germination whereas, ABA is involved in the establishment and maintenance of dormancy. GA exerts its influence in two manners, first by increasing the growth potential of embryo and second by inducing hydrolytic enzymes.