Influence of kinetin on storage protein mobilization and ultrastructure of plastids in excised lupine cotyledons grown in darkness

Storage protein disappeared first from the peripheral and later from central parts of the lupine cotyledon. Kinetin (500 μM) stimulated this process; its effect was most prominent after longer times of incubation. In plastids large, crystalline prolamellar bodies were observed. They some-times split into smaller parts during the course of the experiment, especially in the kinetin-treated material. Kinetin in darkness did not stimulate formation of thylakoid membranes (neither grana nor primary lamellae).

Multifunctional role of plant cysteine proteinases.

Cysteine proteinases also referred to as thiol proteases play an essential role in plant growth and development but also in senescence and programmed cell death, in accumulation of storage proteins such as in seeds, but also in storage protein mobilization. Thus, they participate in both anabolic and catabolic processes. In addition, they are involved in signalling pathways and in the response to biotic and abiotic stresses. In this review an attempt was undertaken to illustrate these multiple roles of cysteine proteinases and the mechanisms underlying their action.