The improving seed physiological aspects of black seed (Nigella sativa L.) in calcareous soil: Seed phosphorus content affected by mother plant nutrition

In order to investigate the effects of increasing soluble phosphorus (P) on seed production and quality of black seed (Nigellasativa L.) in a calcareous soil, a field experiment was conducted at Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013. Field experiment was conducted as factorial layout based on a complete randomized block design with four replications. The fertilizer resources (vermicimpost (V) + Tiobacilus (T), Sulfur (S) + T, V+S+T and control) and three levels of P (0, 30 and 60 kg.ha-1) were the first and second experimental factors, respectively. Seed vigor was also assessed by radicle emergence (RE) test for further evaluation of the effects of P on mother plant on the quality of producing seeds. A germination percentage at day 4 was used as seed vigor test. The resources of soil amendment (V+T, S+T and V+S+T) significantly decreased the P concentration in coat, P percentage of coat to seed and mean germination time. For instance, by applying V+S+T, P concentration in coat and mean germination time were decreased by 18 and 10%, as compared to control treatment.However, 1000 seed weight, seed vigor, P concentration in embryo and seed were significantly increased by applying the resources of soil amendment. There was a significant negative relationship between 1000 seed weight and P concentration in coat (R2= 0.66 **). It seems that under P-deficient conditions in soil, mother plant prefer to produce more longevity seeds, instead to increase theseed vigor, by increasing the P allocation to seed coat