The influences of Bio-stimulator Compounds on growth, essential oil and chemical composition of chamomile plants grown under water stress

Abstract

This study was conducted at the Experimental Nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, during the two successive seasons of 2013/2014 and 2014/2015. This work aimed to investigate the effect of water stress and bio- stimulator on the vegetative growth, flower yield, essential oil production and chemical compositions of Chamomile ( Matricaria chamomilla L.). Water stress was imposed by three different irrigation intervals (4, 8 and 12 days). The plants received different irrigation intervals were sprayed every 2 weeks with bio-stimulator of either Amino Suam or Setter-2 at concentration of 500, 1000 and 2000 ppm for each one, while the control plants were sprayed with tap water. The experimental units were designed in randomized complete block design (RCBD) with 21 treatments and three replications for everyone treatment. The results showed that, highest values of plant height, number of branches/plant , diameter of flower heads, essential oil percentage, total chlorophylls content and total carbohydrates percentage were obtained from irrigation interval of 8 days as a compared to 4 or 12 days. Increasing irrigation intervals from 4 to 8 or 12 days resulted in a significant reduction in the stem diameter, fresh and dry weights of the herb, number of flower heads/plant, fresh and dry weights of flower heads, essential oil yield, as well as N, P and K% in dried herb while proline content was increased with increasing intervals. On the other hand, in most cases all the studied parameters were increased significantly as a result of spraying plants with either concentration of Amino Suam or Setter-2 compared to control plants. Regarding the effect of interaction between the two studied factors, the results indicate that in most cases, plants irrigated every 4, 8 and 12 days and sprayed with any concentration of bio-stimulators (Amino Suam or Setter-2) had the values for all the studied parameters which were significantly higher than those of control plants. Concerning essential oil composition, α-bisabolol oxide A, α-bisabolol oxide B, farnesene, bisabolone oxide, α-bisabolol and Chamazulene were the six major compounds of Chamomile oil. The highest percent of α-bisabolol oxide A (53.50%) were obtained from plants irrigated every 12 days and sprayed with Setter-2 at concentration of 2000 ppm and the highest percent of α-bisabolol oxide B (16.99%), farnesene (12.55%) and bisabolone oxide (12.03%) were resulted from plants irrigated every 8 days and sprayed with Amino Suam at 1000 ppm, while the highest percent of α-bisabolol (6.36%) and Chamazulene (4.37%) were obtained from plants irrigated every 4 days and sprayed with Amino Suam at 2000 ppm.