Free and Conjugated Iaa and Paa in Developing Seeds of Two Varieties of Pigeon Pea (cajanus Cajan)

The endogenous levels of indole-3-acetic acid (IAA) and phenyl acetic acid (PAA) were estimated in developing seeds of two different varieties of Cajanus cajan: Black seeded variety (V1, big seeded) and B. D. N2 (V2, small seeded). Antibodies against IAA and PAA were raised in rabbits. By competitive ELISA, free and conjugated IAA and free forms of PAA were estimated. Growth analysis of seeds was performed by measuring fresh weight, dry weight and water content. All growth parameters studied showed that V1 had higher dry weight, rate of dry matter accumulation and water content when compared with V2. In both varieties, free IAA increased gradually with seed age. The level of conjugated IAA increased approximately twice, but in the bigger seeds conjugated IAA was present at the time of seed maturation, while in smaller seeds, conjugated IAA synthesis started parallel to dry matter accumulation. The role of conjugated IAA in controlling seed size is discussed. PAA content was also higher in V1 compared to V2. The role of auxins in C. cajan seed development is discussed.