FACTORS INFLUENCING THE GERMINATION OF SEEDS OF FALLUGIA-PARADOXA (ROSACEAE)

Freshly matured seeds (achenes) of Fallugia paradoxa (D. Don.) Endl. e x Torr. (Rosaceae, Apache Plume) appear to be nondormant. Seeds readil y germinated without special treatment at 5-10-degrees-C (51 percent) and 20-25-degrees-C (85 percent). When persistent styles were removed and seeds were otherwise placed in the same light and temperature cond itions, germination was significantly higher for seeds with detached s tyles (89 percent) compared to seeds with intact styles (69 percent). In a light gradient, germination decreased as light levels increased. Greatest germination was 32 percent for the lowest light level tested (PPFD 115 muM.m-2-sec-1). At the highest light level tested (PPFD 1291 muM.m-2-sec-1), germination was reduced to 10 percent. For seeds buri ed in soil at depths of zero, one, two, five, and ten millimeters the greatest emergence was 30 percent at a depth of two millimeters, while only two percent of the seeds buried at ten millimeters reached the s urface. For F. paradoxa, seed germination soon after dispersal may per mit early growth to take place during a period when moisture is most l ikely to be available; thereby, allowing some seedlings to establish b efore less favorable moisture and temperature conditions are initiated . Light and soil depth experiments suggest that germination during thi s period may be favored in microhabitats where light and evaporation l evels are at least initially reduced.