抄録
Sago palm seedlings were grown in a culture solution with individual exclusion of macro- (N, P, K, Ca, Mg) and micronutrients (Fe, B, Cu) during their early growth stages. In addition, control, tap water (no nutrient supply) treatment and treatments with half (N½) and twice (N2) the N concentration of that of the control were used. The N2 treatment accelerated the increase of plant length and leaf production from 42 and 70 days after the start of the treatments, respectively. The differences in the total plant length and number of leaves, shoot base diameter and dry weight, and total N uptake were significant between the N2 and N½ treatments. The -N treatment and tap water treatment showed a similar effect on the growth, namely inhibition of the increase of plant length and of leaf emergence as well as of all the growth characters examined. The -N treatment also reduced significantly the SPAD value and root dry weight. The -P treatment reduced significantly the plant length, leaf area, shoot base diameter, total plant dry weight and the uptake of each nutrient, although the total N concentration in the petioles and roots was significantly higher than in the control. No significant effects on the growth characters and nutrient uptake were observed in the -B and -Cu treatments, except for the total plant length in the -Cu treatment and total B uptake in the -B treatment. Due to a probable enrichment of K, Ca, Mg, and Fe by the vermiculite used as medium, the growth and nutrient uptake of the seedlings grown under the -K, -Ca, -Mg, and -Fe treatments were similar to these of the control. In conclusion, the growth responses of sago palm seedlings to the deficiencies of N and P were remarkable, compared to those to the other nutrient deficiencies. In future, more precise studies for the -K, -Ca, -Mg, and -Fe treatments should be carried out.
