Influence of exogenous polyamines on antioxidant defence and essential oil production in valerian (Valeriana officinalis L.) plants under drought stress

Abstract

The objective of this study was to determine the effects of foliar application of polyamines (PAs) on antioxidant defence and essential oil production of valerian (<em>Valeriana officinalis</em> L.) grown under different drought stress treatments (100, 70, 50 and 30% available water content). This study was carried out using pots in greenhouse condition. Drought–stressed valerian seedlings were sprayed with 1 mM concentration of each putrescine (Put), spermidine (Spd) and spermine (Spm). The results showed that drought stress significantly affected most biochemical characteristics of valerian plants. Characteristics including leaf relative water content, chlorophyll a and b contents were decreased, while carotenoids and electrolyte leakage were increased with the increase of water stress. In this research, defensive characteristics comprising proline content, soluble sugars, catalase, and ascorbate peroxidase were increased followed by drought stress to ameliorate the adverse effect of it. Results revealed that foliar application of Spd and Spm provoked the antioxidant enzymes activity as well as proline accumulation in valerian which alleviate the membrane damages. Consequently, Spd and Spm increased photosynthetic pigments which act as energy supply for plant growth and production. Here, putrescine had detrimental effects on CAT activity and Chl a content. Albeit, PAs presented remarkable effects under moderate drought stress condition but it showed reverse trends in severe drought stress condition. In terms of quantity and quality yield, drought stress reduced root growth but increased the concentration of essential oils. PAs are able to alleviate water deficit-induced diminish root growth. These results suggest that in moderate drought stress, growers can use PAs to increase productivity valerian.

Back to the Roots—An Overview of the Chemical Composition and Bioactivity of Selected Root-Essential Oils

“…However, very severe drought stress conditions (30% available water content) led to reverse trends. Although the exogenous application of polyamines (growth regulators) was ineffective on EO accumulation, it alleviated reverse effects of stress on plants by increasing root growth and consequently improving EO yield [330]. These results are in line with another study, where reduction of valerian EO content induced by water stress was compensated by increasing root yield as a result of bio-fertilizer (rhizospheric bacteria and arbuscular mycorrhizal fungi) application [329].…”

“…Results also indicated positive correlation between photosynthesis and EO content [ 328 ]. With regard to productivity optimisation in a scenario of drought and climate change, several publications evaluated the effect of drought stress on qualitative and quantitative traits of V. officinalis [ 329 , 330 ]. Root growth decreased with increasing water shortage, while the EO content was positively affected by moderate drought stress treatment (50% available water content).…”

Exogenous Application of the Polyamine Spermine Delays Natural Leaf Senescence in Wheat Through Protecting Chlorophyll from Degradation and Preventing Oxidative Stress

“…Delayed leaf senescence was found to be associated with a higher Spm level, reduced reactive oxygen species (ROS) production (Sobieszczuk-Nowicka, 2017). Our results are in accordance with many studies (Amooaghaie and Moghym, 2011;Minocha et al, 2014;Mustafavi et al, 2016) where exogenous PAs alleviate growth inhibition possibly due to the protection of membranes and minimization of oxidative damage.…”

“…Many changes during leaf senescence can be inhibited by the application of exogenous PAs (Cai, 2009). Accordingly, the maintenance of photosynthetic pigments in Spm-treated plants with enhanced growth and production is in accordance with Mustafavi et al, (2016). Chloroplasts are the first organ to undergo disorganization during leaf senescence, and chlorophyll catabolites are transported and accumulated in the vacuole (Ling and Jarvis, 2016).…”

Effect of L-Ornithine application on improving drought tolerance in sugar beet plants

“…First, polyamines may play a critical role in drought stress signalling to confer adaptive responses (Pottosin and Shabala, 2014). Moreover, Mustafavi et al. (2016) reported that the polyamines control over the balance between ROS production and scavenging may “shape” H 2 O 2 signal.…”