The effect of desiccation on the longevity of seeds of Araucaria hunsteinii and A. cunninghamii
Seeds of Araucaria hunsteinii K. Schum. dried quicker at 29°C than at 19°C and quicker with the seed-coat removed than when intact; seeds enclosed in polyethylene bags increased in moisture content. At 15°C, seeds in a flow of air dried quicker than seeds in a box with silica gel, which in turn dried quicker than seeds in a box with no desiccant. No loss of germination ability occurred on drying fresh seed from 53 to about 32 per cent moisture content (fresh weight basis); during further desiccation the percentage germination was related to percentage moisture content in the form of a sigmoid curve, culminating in a complete failure to germinate at approximately 14 per cent moisture content. A consistent relationship was observed for all treatments and the mean critical moisture content for seed death (failure to germinate) was near 23 per cent. Excised embryos grew on 1 per cent agar but died if previously subjected to 14 h of desiccation at 15°C. In contrast, no relationship was found between germination and moisture content of A. cunninghamii D. Don on desiccation from 21 to 7 per cent moisture content. Possible causes for the observed difference in response to desiccation are discussed and methods for seed storage are considered.
TOMPSETT, P.B. (1982). The effect of desiccation on the longevity of seeds of Araucaria hunsteinii and A. cunninghamii. Annals of Botany. 50 (5) pp. 693-704.