Growth responses of Lavandula pubescens to temperature regimes of Tabuk, Saudi Arabia

Abstract

Tabuk region of Saudi Arabia is characterized by highly variable environmental conditions where temperature goes extremely low to extremely high and affects the morphology, growth, physiology and biochemistry of the plants. In this research, we investigated the growth and stress tolerance in a medicinally important plant, namely Lavandula pubescens (family Lamiaceae) in response to temperature dynamics. The plant samples were collected from Tabuk-Jorden road on the 15th day of January, April, July and October 2013. Plant height, fresh and dry matter, total chlorophyll nitrogen (N), phosphorus (P) and potassium (K), leaf relative water contents were determined in terms of growth of the plant. Physiological and biochemical parameters of plants like activity of carbonic anhydrase (CA), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and leaf protein contents were also determined. Plant growth parameters showed a significant increase in height, fresh and dry matter accumulation, total chlorophyll, NPK and leaf relative water contents investigated in the month of April and October 2013. Plant growth was suppressed and an active role of CAT, POD and SOD was observed to cope with the extremely low temperature in January and extremely high temperature in July 2013. Therefore, based on the results it is recommended that during April and October the environmental conditions are best suitable for growth, development and medicinal use of Lavandula. However, the plants are also found capable to adapt and tolerate the temperature regimes in different seasons of Tabuk.