EFFECT OF SPRAYING SOME SAFE GROWTH STIMULANTS ON GROWTH AND FLOWERING OF PETUNIA AXILLARIS UNDER DROUGHT STRESS

Abstract

The current investigation has been accomplished in a climate of the greenhouse at the farm of the Fac. of Agri, Damanhour Univ., El-Beheira Gov., Egypt, during two consecutive seasons of 2020/2021 and 2021/2022. The aim of this experiment was to evaluate the impact of two safe growth stimulants: seaweed extract of Oligo-x (SWE) and chitosan (CH) each at 0, 3 and 6 ml/l on vegetative growth, flowering growth, and the chemical composition of the leaves of Petunia axillaris plants cultivated in drought stress conditions. The acquired results for the two seasons showed that drought stress caused serious negative consequences on vegetative growth, flowering growth, and the chemical composition of leaves, while it increased the proline content and electrolyte leakage. Generally, seaweed extract and chitosan had a profound impact on the studied characteristics. For instance, the growth parameters including plant height, number of branches per plant, leaf area, shoot fresh and dry weights per plant, as well as root length and root fresh and dry weights per plant showed the highest values via the application of seaweed extract at 6 ml/l compared to the other treatments under study. In the same line, flowering parameters such as flowering duration, flower diameter, the number of flowers per plant, flower fresh and dry weights, and leaves chemical composition including total leaf carbohydrate exhibited the most significant improvements by the application of seaweed extract at 6 ml/l. On the contrary, the seaweed extract at 6 ml/l resulted in the lowest value of proline content, and electrolytic leakage. Regarding the chitosan treatment, the 6 ml/l concentration of the solution exhibited the highest values of the number of days to flowering, flower longevity and SPAD index in relative to the other treatments. All the studied traits were expressed using cross correlation analysis.

Keywords

• seaweed extract
• algae extract
• chitosan
• petunia axillaris
• drought stress