# Exposure to Light of the Abaxial versus Adaxial Side of Detached Kalanchoë blossfeldiana Leaves Affects Anthocyanin Content and Composition Differently

## TL;DR

Exposing the upper or lower sides of detached Kalanchoë leaves to light affects anthocyanin levels differently, with some compounds increasing only when the upper side is lit.

## Contribution

The study reveals that light exposure on different leaf sides and methyl jasmonate application influence anthocyanin accumulation in distinct ways.

## Key findings

- Exposing the abaxial side to light increases specific anthocyanin derivatives.
- Methyl jasmonate inhibits the accumulation of certain anthocyanins when applied to the abaxial side.
- Anthocyanin composition varies based on leaf orientation and treatment.

## Abstract

The accumulation and composition of anthocyanins in leaves of Kalanchoë blossfeldiana, detached and kept for five days under natural light conditions, were investigated. The presence of fifteen derivatives of cyanidin, petunidin, and delphinidin was found. Changes in the content of each anthocyanin in the leaves before and after exposure to light on the abaxial (naturally upper) and adaxial (naturally lower) sides of the leaves were compared. When the adaxial side was exposed to light, the anthocyanin contents of the leaves did not change. In contrast, when the abaxial side of detached leaves was exposed to light, there was enhanced accumulation of delphinidin-rhamnoside-glucoside, cyanidin-rhamnoside-glucoside, cyanidin-glucoside-glucoside, and two unknown derivatives of petunidin and delphinidin. Application of methyl jasmonate (JA-Me) on the abaxial side exposed to light inhibited the accumulation of these anthocyanins. This effect could probably be due to the presence of these anthocyanins in the epidermal cells of K. blossfeldiana leaves and was visible in the microscopic view of its cross-section. These anthocyanins were directly exposed to JA-Me, leading to inhibition of their formation and/or accumulation. The lack of significant effects of JA-Me on anthocyanin mono- and tri-glycosides may indicate that they are mainly present in the mesophyll tissue of the leaf.