Desiccation tolerance in two species with recalcitrant seeds: Clausena lansium (Lour.) and Litchi chinensis (Sonn.)

Abstract

1994). Desiccation tolerance in two species with recalcitrant seeds: Clausena lansium (Lour.) and Litchi chinensis (Sonn.). AbstractSeeds were collected at weekly intervals from mid-maturation to the fully ripened stage As seed development progressed, desiccation tolerance increased Desiccation tolerance of C lansium seeds was greatest at 67 days after anthesis (DAA), when they tolerated air drying for 9 days; 74 DAA was considered as physiological maturity, and their full viability was only maintained for up to 3 days of drying; overnpened seeds (88 DAA) had the lowest desiccation tolerance In L. chinensis, the desiccation sensitivity of seeds at 98 DAA (fully mature) was higher than that at 84 and 91 DAA (less mature); among the excised embryonic axes at different developmental stages, the less mature ones were less sensitive to desiccation than the fully mature ones; excised embryonic axes of the same stage were more tolerant of desiccation than whole seeds

A comparison between Theobroma cacao L. zygotic embryogenesis and somatic embryogenesis from floral explants

“…It is equal to 50% in cork oak (Finch-Savage and Blake, 1994) and 45% in litchee, another plant with recalcitrant seeds (Fu et al, 1994). Water status enables a distinction to be made between recalcitrant and orthodox seeds whose water content can be as low as a few percent: 6.9%, for example, in Ricinus (Kermode and Bewley, 1985).…”

Heat Stable Proteins and Desiccation Tolerance in Recalcitrant and Orthodox Seeds

“…Germination percentage is usually used as an index of desiccation tolerance (Koster and Leopold, 1988;Blackman et al, 1991;Fu et al, 1994). However, sometimes the germination percentage is inappropriate as when immature seeds are unable to germinate.…”

“…It was shown that the membrane of embryonic axes at physiological maturity was unimpaired and more tolerant to desiccation, but those of immature and overripe ones was less tolerant. The dry weight ofwampee seeds increased rapidly from 50 to 70 DAA (Fu et al, 1994), but protein synthesis rate decreased in later stages of development (data not shown).…”

“…Clausena lansium (wampee) seed is recalcitrant (Fu et al, 1989a,b;Hoffmann and Steiner, 1989). Fu et al (1994) reported that desiccation tolerance ofwampee seeds im;reased to a maximum value and then decreased during seed development and maturation. In contrast, desiccation tolerance of peanut axes (an orthodox seed) increased during seed development and maturation.…”

“…However, desiccation tolerance in recalcitrant seeds may be different from that in orthodox seeds. Recent data have shown that desiccation tolerance was acquired gradually during maturation of developing seeds (Leprince et al, 1990;Sun and Leopold 1993;Fu et al, 1994). There were no LEA proteins in Avicennia marina (Farrant et aI., 1992) but Finch-Savage (1994) stated that proteins which have homology with dehydrins have been identified immunologically in mature seeds of five desiccation sensitive tree species.…”