Physiological analysis of drought stress influenced by Claroideoglomus claroideum inoculation of in vitro or seed-propagated Coleus forskohlii Briq plants

The effect of inoculation with arbuscular mycorrhizal fungi Claroideoglomus claroideum on Coleus forskohlii (Willd.) Briq. plants propagated by seeds or in vitro, and subsequently exposed to drought stress has been studied. Stress tolerance and yield stability are closely related to coping with oxidative stress, which occurs at prolonged water deprivation.The plants inoculated with Claroideoglomus claroideum were grown in well-watered and drought-stressed conditions. The parameters of the inoculation with arbuscular mycorrhizal fungi (root colonization, total and easy-extractable-glomalin-related soil proteins, acid and alkaline phosphatases in roots and soil) and antioxidant activity (enzyme and non-enzyme parameters) were evaluated. In the inoculation of in vitro and in vivo propagated Coleus forskohlii (Willd.) Briq.with arbuscular mycorrizal fungi (AMF), an increase in the growth parameters, the activity of enzymes with antioxidant capacity and the content of total phenols and flavonoids and water- and lipid-soluble metabolites with antioxidant capacity were recorded compared with non inoculated plants. The results showed that arbuscular mycorrhizal fungi Claroideoglomus claroideum activate plants' antioxidant system, leading to reduced oxidative stress damage. The reduction in oxidative stress markers (hydrogen peroxide, malondialdehyde and proline) content as a result of AMF inoculation was higher in adapted in vitro propagated plants compared to in vivo plants. The same trend is observed in drought stressed plants. When grown in water-deficient conditions, adapted micro-propagated plants showed higher plant growth parameters such as shoot height, root length, plant biomass, antioxidant activity, and lower levels of oxidative stress markers, suggesting that they are more resistant to drought than the individuals which were grown from seeds.

Automated summary

This study found that inoculation with arbuscular mycorrhizal fungi Claroideoglomus claroideum can enhance the antioxidant capacity of Coleus forskohlii plants and reduce oxidative stress damage caused by drought stress. Micro-propagated plants showed higher resistance to drought compared to plants propagated from seeds.