In vivo two-photon FLIM resolves photosynthetic properties of maize bundle sheath cells

Abstract

Maize (Zea mays L.) performs highly efficient C4 photosynthesis by dividing photosynthetic metabolism between mesophyll and bundle sheath cells. In vivo physiological measurements are indispensable for C4 photosynthesis research as any isolated cells or sectioned leaf often show interrupted and abnormal photosynthetic activities. Yet, direct in vivo observation regarding bundle sheath cells in the delicate anatomy of the C4 leaf is still challenging. In the current work, we used two-photon fluorescence-lifetime imaging microscopy (two-photon-FLIM) to access the photosynthetic properties of bundle sheath cells on intact maize leaves. The results provide spectroscopic evidence for the diminished total PSII activity in bundle sheath cells at its physiological level and show that the single PSIIs could undergo charge separation as causal. We also report an acetic acid-induced chlorophyll fluorescence quenching on intact maize leaves, which might be a physiological state related to the nonphotochemical quenching mechanism.

Plant phenotyping relevance

二光子FLIMを用いて無傷葉の葉鞘細胞の光合成特性・生理状態を直接画像計測しており、植物生理表現型の取得法が研究の中心です。

Code and data availability

The preprint describes in vivo two-photon FLIM measurements on maize leaves but contains no data availability statement, no public phenotype/image dataset, no author code or model deposit, and no supplement reference with such assets. The only analysis tool mentioned, FLIMfit, is a third-party software from Imperial, a

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