Priming Effect of on the Enhancement of Germination Traits in Aged Seeds of Chamomile (Matricaria chamomilla L.) Seeds Preserved in Medium and Long-term Storage

Abstract

Chamomile (Matricaria chamomilla L.) is a widely used medicinal plant possessing several pharmacological effects due to presence of active compounds. In order to study of seed priming effects on seedling growth of chamomile, an experimental design, based on randomized complete design with three replications was conducted under greenhouse conditions in Research Institute of Forests and Rangelands in 2014-2015. Experimental factors were A) three chamomile accessions as code of gene bank 8959 (Brojen), 15123 (Arak) and 23879 (Isfahan), B) five conservation methods including: medium-term storage (active cold room 4 °C for 15 years), long- term storage (basic cold room-18 °C for 15 years), regenerated seeds in open storage 22 °C for 2 years (Control) and aged seed under accelerated ageing )40 °C,98% of relative humidity for 48 and 72h) and C) priming treatments including: without priming /(control), osmopriming (PEG-0.3Mpa), hormonal priming (Gibberllic acid 250 and 500ppm), hydropriming (imbibition with distilled water). Data collected for seed emergence percent, root and shoot length, seedling length, vigor index, seedling weight and three Proxidase, Catalase and Super Oxid Desmotaz (SOD) enzymatic activities. Variance analysis showed significant effects of all factors and their interactions except accession by conservation interaction effects for seedling length (P<0.01). Result showed that that accession two accessions 23789 (Esfahan) and15123 (Arak had higher mean values than one other accessions for most of the traits in both medium-term and long- term storage. For aged seeds, the higher root length, seedling length mean values were obtained in 48h accelerate aging test. In comparisons between priming treatments, the higher means of traits were obtained in osmopriming except germination percent. For enzymes activity the trends of accession were not similar but the effect of osmopriming on catalase activity were high and stable in three accessions. The result of priming by conservation interaction showed that the higher seed emergence was obtained in regenerated seeds (control). The higher root length was obtained in accelerated aging test by application of all of priming treatments except hydropriming. For vigor index, hormonal priming (GA250) had higher effect followed by osmopriming. Similarly, for enzymatic activities GA500 had significant impact on proxidas and catalase. It was proved that two priming technique Osmo-priming using (PEG) and hormonal priming (Gibberllic acid) were effective method for recovery of aged seed.