Studies on seed germination of Stereospermum suaveolens with respect to different parameters

摘要

Stereospermum suaveolens DC. is a valuable medicinal tree species, now placed in the threatened category due to its overexploitation. This species is usually propagated through seeds but has a very poor rate of germination. The right choice of planting substrates and pretreatments given to seeds are important factors influencing germination and growth of the seedlings. The present study was conducted to determine suitable planting substrate(s) and an effective pretreatment for germinating the seeds. The moisture content of one year old seeds was high (15 ± 1.3) and that of the current year (fresh) seeds were low (8.1 ± 0.3). Fresh seeds were pre-soaked overnight in water and then grown in various substrates like coco peat, soil, sand, coco peat / sand (1:1) and coco peat / soil (1:1), filter paper, Murashige and Skoog's medium (MS) and Woody Plant Medium. Results revealed that the optimum seed germination (68%) was recorded in coco peat substrate followed by MS medium (66 %) and lowest rate was in soil (6%). The other germination parameters studied were mean daily germination, which was same in coco peat as in MS medium (2.2), followed by filter paper (2.0). The germination rate was faster in coco peat (5.4) when compared to that on other substrates, while germination index was highest in MS medium (9.9). Coco peat was suitable in terms of germination. The effect of different pretreatments on germination were therefore studied for this substrate. Seeds soaked in distilled water showed maximum percent of germination compared to other pretreatments.