Quantifying the dynamics of light tolerance inArabidopsisplants during ontogenesis

Abstract

The amount of light plants can tolerate during different phases of ontogenesis remains largely unknown. This was addressed here employing a novel methodology that uses the coefficient of photochemical quenching (qP) to assess the intactness of photosystem II reaction centres. Fluorescence quenching coefficients, total chlorophyll content and concentration of anthocyanins were determined weekly during the juvenile, adult, reproductive and senescent phases of plant ontogenesis. This enabled quantification of the protective effectiveness of non-photochemical fluorescence quenching (NPQ) and determination of light tolerance. The light intensity that caused photoinhibition in 50% of leaf population increased from ∼70 μmol m(-2) s(-1) , for 1-week-old seedlings, to a maximum of 1385 μmol m(-2) s(-1) for 8-week-old plants. After 8 weeks, the tolerated light intensity started to gradually decline, becoming only 332 μmol m(-2) s(-1) for 13-week-old plants. The dependency of light tolerance on plant age was well-related to the amplitude of protective NPQ (pNPQ) and the electron transport rates (ETRs). Light tolerance did not, however, show a similar trend to chlorophyll a/b ratios and content of anthocyanins. Our data suggest that pNPQ is crucial in defining the capability of high light tolerance by Arabidopsis plants during ontogenesis.

Enhanced thylakoid photoprotection can increase yield and canopy radiation use efficiency in rice

“…As LAI and F rise, leaves in the lower portions of the canopy will have a lower risk of photoinhibition making an interesting comparison with dynamics of light tolerance during Arabidopsis development. 55 …”

Nonphotochemical Chlorophyll Fluorescence Quenching: Mechanism and Effectiveness in Protecting Plants from Photodamage

“…However, this additional quenching does not contribute to light tolerance, implying that if uncoupled LHCII indeed participates in the NPQ process, as previously suggested (Holzwarth et al, 2009), it would contribute little to protection, a fact rendering the existence of two uncoupled sites for NPQ totally unnecessary. In addition, an interesting trend in light tolerance was observed during ontogenetic development (Carvalho et al, 2015): 1-week-old seedlings are almost 20 times less tolerant to light than established 8-week-old plants. This finding indicates that the most significant high-light damage occurs in young plants or developing leaves.…”

Dynamic non‐photochemical quenching in plants: from molecular mechanism to productivity

“…Both parameters were successfully used for detection of the early signs of photoinhibition (Ruban and Murchie, ; Ruban and Belgio, ; for review see Ruban, , ). The leaf light tolerance can also be determined providing a fundamental parameter for each classes and types of plants acclimated to various environmental conditions (Carvalho et al , ; Ware et al , ,b; Giovagnetti and Ruban, ; Tian et al , ; Giovagnetti et al , ; Wilson and Ruban, ). The novel methodology can be used to build up comprehensive light tolerance databases for various current and emerging varieties of crops that are grown outdoors as well as in artificial light environments, in order to optimize for the best environmental conditions that enable high crop productivity (Ruban, ).…”