Response of fever tea (Lippia Javanica)to fertigation frequency, growth medium and propagation method

Abstract

Fever tea is one of the important medicinal plants belonging to the family Verbenaceae. The leaves of the plant are used as a remedy to treat malaria, stomach pains, colds and fever. There are different clones of Lippia species available with different medicinal value. Therefore, the purpose of this study was to determine protocols for propagation of fever tea so as to multiply an ideal clone. Vegetative propagation of this plant species by stem cuttings, requirements for seed germination and response of fertigation frequencies and growing medium to growth, yield and quality has not been studied. In this study, factors influencing effective propagation of fever tea were studied. Those factors were: cutting position (apical vs. basal), media (pine bark vs. sand), hormone (seradix No. 2 vs. no hormone) light and temperature requirement for fever tea seed germination and effect of fertigation frequencies (0.4 L/day, 1L/day, 2L/day, 2L/2nd day and 2L/week) and growing media (pine bark vs. sand) on growth, oil yield and oil quality. In vegetative propagation by stem cuttings, measurements made were number of roots per rooted cutting, fresh mass, stem circumference and number of leaves and the rate of rooting during four consecutive sampling dates (5, 10, 15 and 20 days after planting). Apical cuttings rooted earlier by 5 days than basal cuttings at 10 days but at 15-20 days after establishment, both cuttings had good rooting. Fresh mass was not affected by cutting position and rooting media, but cuttings performed slightly better when propagated in pine bark medium than sand medium. Basal cuttings resulted in thicker stems and more leaves as compared to apical cuttings. Seradix No.2 (0.3% IBA) hormone increased the fresh mass, stem circumferences, root number and leaf numbers on both apical and basal cuttings. For the establishment of fever tea stem cuttings, both apical and basal cuttings can be used but pine bark is the ideal medium. The cuttings can be ready for transplanting in 15-20 days after establishment and Seradix No. 2 (0.3% IBA) promotes rooting of fever tea cuttings. The ideal combination of light and temperature for seed germination of fever tea was investigated. Germination was tested at constant temperature regimes (15, 20, 25 and 30¨¬C with continuous light or dark period and alternating temperatures of 20:30 and 16L: 8D (light: dark) combinations respectively. Seeds started to germinate after 8 days from incubation and the last germination was observed at 30 days from incubation. Germination percentages increased at 20-30 constant temperatures and 20/30 alternating temperatures but the difference amongst them was not significant. Higher germination of 86% were achieved when seeds were exposed to continuous light than alternating light and dark. Seeds failed to germinate in continuous darkness. Fever tea seeds were positively photoblastic. The effect of fertigation frequency and growing medium on the growth, yield and quality of fever tea were investigated in a tunnel. Treatments used were five fertigation frequencies (0.5L/day, 1L/day, 2L/day, 2L/2nd day, and 2L/week) and two growing media (pine bark and sand). Measurements made were plant height, stem circumference and number of branches at 8, 16 and 32 weeks after planting. At 8 weeks after planting all fertigation frequencies improved fever tea growth except fertigation frequency of 2L/week. All the fertigation frequencies were ideal to sustain the growth and development of fever tea plants except 2L/week. At 16 weeks after planting there were interactive effects between fertigation frequencies and the growing medium for the plant height of fever tea. Plants fertigated with 2L/day grown in sand media grew taller than all the other fertigation frequencies. At 32 weeks after planting there was a significant effect on the plant height from the main effects of fertigation frequency and growing medium. Plants fertigated with 2L/day were significantly the tallest followed by plants fertigated with 0.5L/day, 1L/day, 2L/2nd day and 2L/week. When plants were younger better plant growth was obtained in pine bark media. Stem circumference and number of branches of fever tea were significantly affected by fertigation frequency and growth medium. At 16 and 32 weeks after planting, plants grown in sand media had thicker stems and more branches as compared to plants grown in pine bark media. The essential oil of fever tea was extracted using hydro-distillation. Fertigation frequency did not affect oil yield. Plants grown in pine bark media yielded more oil than plants grown in sand medium. Microscopical studies using scanning electron microscope were investigated to determine the development of oil glands and trichomes on the abaxial (upper) and adaxial (lower) surfaces of the leaves as affected by fertigation frequency and the growing medium. There were no significant effects on the number of oil glands and trichomes developed on both surfaces of the leaves. Pine bark medium resulted in larger oil glands than sand medium regardless of the treatments, and pine bark also yielded more oil percentages than sand medium. Based on this investigations for commercial production of fever tea essential oil pine bark media is recommended. Chemical compounds of fever tea oil were also not affected by fertigation frequency or growth medium. In this study the chemical compounds detected from essential oils of fever tea were monoterpenes (i.e. ¥á-pinene, sebinen, 1.8 cinede, myrcene, ipsenone and ipsedienone) and the sesquiterpenes (i.e. ¥â-caryophyllene and germacrene-D). Compounds that gave the smallest chemical percentages and the shortest time to be detected were ¥á-pinene, sebinen, 1.8 cinede, myrcene, ipsenone and ipsedienone. Compounds found with the highest chemical percentages with highest peaks were ¥â-caryophyllene and germacrene-D.