Author : Baran Wirawan

Summary : Response to desiccation is dependent on physiological status of the seed, therefore it could be hypothesized that orthodox and recalcitrant seeds will exhibit parallelism in their response to desiccation if viewed from the entire stage of seed development and germination. The objective of the study is to determine the parallelism between soybean (Glycine max L. Merr) orthodox and cacao (Theobromo cacao L.) recalcitrant seeds in relation to desiccation from the stage of seed development to germination. The studies conducted were : (1) desiccation of soybean seed at different stages of seed development before physiological maturity, (2) desiccation of physiological mature soybean seed at different stages of seed germination (phase I,II, radicle protrusion, and phase III), (3) seed development and maturity of cacao, (4) desiccation of cacao seed at different stages of pre and post physiological maturity, and (5) initiation of germination of cacao seed after physiological maturity. Results confirmed the parallelism of soybean and cacao seeds in response to desiccation. At immature stage 25 days after anthesis (DAA) for soybean and 4.5 months after anthesis (MAF) for cacao both seeds are desiccation-sensitive. Soybean seeds become desiccation-tolerant at 30-35 DAA (slow drying) and 40 DAA (fast drying). In cacao this stage corresponded to 5 MAF irrespective of drying rate. Another desiccation-sensitive stage was observed at 18 hours after imbibition (radicle protrusion stage) and 5.5 MAF of soybean and cacao, respectively.