Impact of Soil Field Water Capacity on Secondary Metabolites, Phenylalanine Ammonia-lyase (PAL), Maliondialdehyde (MDA) and Photosynthetic Responses of Malaysian Kacip Fatimah (Labisia pumila Benth)

Abstract

A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL) and malondialdehyde (MDA) activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER) (100%; well watered), (75%, moderate water stress), (50%; high water stress) and (25%; severe water stress). The production of total phenolics, flavonoids, anthocyanin, soluble sugar and relative leaf water content was affected by the interaction between varieties and SWC. As the ER levels decreased from 100% to 25%, the production of PAL and MDA activity increased steadily. At the highest (100%) ER L. pumila exhibited significantly higher net photosynthesis, apparent quantum yield, maximum efficiency of photosystem II (fv/fm) and lower dark respiration rates compared to the other treatment. The production of total phenolics, flavonoids and anthocyanin was also found to be higher under high water stress (50% ER replacement) compared to severe water stress (25% ER). From this study, it was observed that as net photosynthesis, apparent quantum yield and chlorophyll content were downregulated under high water stress the production of total phenolics, flavonoids and anthocyanin were upregulated implying that the imposition of high water stress can enhance the medicinal properties of L. pumila Benth.

Changes in Plant Water Status, Biochemical Attributes and Seed Quality of Black Gram and Green Gram Genotypes under Drought

“…In our investigation, total flavonoids and anthocyanin content was found to increase in stressed plants of both black gram and green gram ( Fig. 2-C, D, E, F) which is in consistent with earlier findings (Jaafar et al, 2012;Baroowa and Gogoi, 2013). This increased level of anthocyanin contents were associated with an enhanced resistance to water loss as the glycosides attached to the anthocyanin in vacuoles adjust the osmotic potential of the cells, thereby minimizing the water loss through evapotranspiration (Chutipaijit et al, 2008).…”

“…Under drought, increased production of secondary metabolites like flavonoids and phenolics is often observed in plants which is beneficial for resisting the adverse effect of drought (Jaafar et al, 2012 Santos et al, 2004). However, in most of the plant species, these biochemical and physiological modifications are not sufficient for survival when severe drought conditions remain constant over time.…”

New insights explain that drought stress enhances the quality of spice and medicinal plants: potential applications

“…In the same manner, in stressed peas (Pisum sativum), the overall amount of anthocyanins (product of biomass and anthocyanin concentration) is about 25 % higher as in plants cultivated under standard conditions (Nogués et al 1998): although the biomass of the stressed pea plants is only about one third of the control plants, the massive increase in the concentration of phenolic compounds still resulted in a real increase of anthocyanins in the stressed plants. In the same manner, Jaafar et al (2012) reported that not only the concentration but also the overall production of total phenolics and flavonoids per plant is enhanced in plants suffering drought stress, although the explicit data on biomass per plant are not displayed by the authors. In contrast, the overall yield of flavonoids was nearly the same, when the plants were either grown under drought stress or under well-watered, non-stress conditions.…”

Effect of climate conditions on total phenolic content and antioxidant activity of Jatropha dioica Cerv. var. dioica

“…Furthermore, as the level of drought increases, the level of oxidative stress in the cells and tissues of plants also increased, which implies the initiation of lipid peroxidation. Therefore, the increase in antioxidant levels is attributed to its free radical scavenging capacity, which avoids lipid peroxidation, thus maintaining a cell membrane free of injury (Jaafar et al, 2012). As can be observed in Figures 1 and 2, the results of the TPC, TFC and radical scavenging activity were higher in the rhizomes than in the stems.…”