Investigations on the responses of cumin plants to certain horticultural agro-chemicals. I. influences of Gibberellic acid (GA_3) on foliage growth, fruit yield, essential oil and chemical compositions

摘要

The uses of agro-chemicals, in improving plant growth and development of horticultural crops is very crucial, particularly, when it comes to horticultural edible fruits. A split plot experiment with four replicates was conducted in the field, underAssiut-Egypt conditions. This investigation was initiated to evaluate the performance of cumin plants different traits and parameters, as influenced by different concentrations of Gibberellic acid (zero, 250, 500 and 1000 ppm), analogous to what is foundin nature as agrochemical pollutant, applied by different methods of application (1- initial pre-planting fruit soaking. 2- initial pre-planting fruit soaking plus one post emergence spray application. 3- initial pre-planting fruit soaking plus two post-emergence spray applications. Gibberellic acid (GA_3) concentrations increased plant height, foliage and root dry weights and root length, over the untreated control. It also improved fruit yield and weights. Cumin essential oil content and oil yield per plant were remarkably increased by GA_3 application, especially at 250 ppm. Higher concentrations tended to exhibit minimizing trend for these parameters. GLC analyses indicated that gibberellic acid noticeably reduced #alpha#-Phellandrene and immensely increased myrcene and cumin aldehyde, as major active constituents, in cumin fruit essential oil. It slightly reduced cumin photosynthetic pigments. It also increased nitrogen and protein content in cumin fruits. Supplemental two times pest-emergence sprays in addition to the initial pre-planting soaking of cumin fruits were beneficial to cumin vegetative growth and fruit yield, in comparison to cumin initial fruit soaking alone. However, this treatment reduced volatile oil yield per plant. The mutualinteractive effects of GA_3 concentration, especially at 1000 ppm applied as two supplemental sprays in addition to the initial fruit soaking' resulted in the production of the highest cumin plants, as compared with untreated controls or those initiallysoaked in 250 ppm.