Effects of desiccation and temperature on the germination of Shorea chinensis (Dipterocarpaceae) seeds

Yan, X. F.

SEED SCIENCE AND TECHNOLOGY

2007

35

1

Cao, M

The present study examined the seed desiccation sensitivity under different drying regimes and evaluated the effects of dehydration and lower temperature on the seed germination of Shorea chinensis (Wang Hsie) H. Zhu. The results showed that this seed possesses high moisture content (MC) and germinate soon after dispersal. The MC of the seeds was about 100% (d. wt) soon after dispersal. The germination percentage (GP), coefficient rate of germination (CRG), germination index (GI) and vigor index (VI) were calculated for monitoring the decline of seed viability. The critical MC was inconsistent between different drying regimes (with the values ranging from 0.81 to 0.74 g/g). Seed viability was completely lost when they were dried to about 46-45% MC, which was identified as the lethal MC. The seeds incubated at both 15 degrees C and 5 degrees C (transferred to 30 degrees C after 10-day incubation) achieved higher final GP than those at 30 degrees C, but the lower temperatures obviously delayed the germination course. Shorea chinensis seeds could be stored at 15 degrees C for 5 days without a significant decrease in viability. However, the fact that the viability of the seeds was partially lost after being stored at 5 degrees C for one day and completely after 3 days, together with the intolerance of the seeds of this species to desiccation, indicate their recalcitrant nature.