Effects of clone and fertilization on the seed and foliar chemical composition of Scots pine (Pinus sylvestris) grafts

Abstract

Effects of clone and fertilization on the seed and foliar nutrient concentrations of Scots pine grafts were investigated in a seed orchard in southern Finland. The seed and foliar samples for chemical analyses were collected during winters 1985–86 and 1988–89 from 39 grafts per clone fertilized in spring 1986. There were 6 clones and 13 treatments for each clone with three replications. The treatments consisted of N, P, K in various combinations, micronutrients, wood ash and grass control. Macro- (N, P, K, Ca, Mg) and micronutrients (Cu, Zn, B) were analysed. There were statistically significant differences between the clones in seed nutrient concentrations. The variation of the K, Mg, Ca, Zn and Cu concentrations between the two study years was considerably larger in the seeds than in the needles. The concentrations of these elements in the seeds were low in the year of an abundant seed crop in spite of fertilization. This had, however, no negative effects on germination of seeds. The proportions of crude fat and crude protein were high in both years (34% and 35% in 1985 ; 33% and 38% in 1988). Fertilization had only minor or no effect at all on the seed chemical composition in the orchard with a satisfactory nutrient status of the soil. Also on the foliar nutrient concentrations the effect of the clone was stronger than that of fertilization. Grafts with large needles produced heavy seeds, which had more storage proteins than the lighter seeds.