Leaf growth in early development is key to biomass heterosis in Arabidopsis

Abstract

Arabidopsis thaliana hybrids have similar properties to hybrid crops, with greater biomass relative to the parents. We asked whether the greater biomass was due to increased photosynthetic efficiency per unit leaf area or to overall increased leaf area and increased total photosynthate per plant. We found that photosynthetic parameters (electron transport rate, CO2 assimilation rate, chlorophyll content, and chloroplast number) were unchanged on a leaf unit area and unit fresh weight basis between parents and hybrids, indicating that heterosis is not a result of increased photosynthetic efficiency. To investigate the possibility of increased leaf area producing more photosynthate per plant, we studied C24×Landsberg erecta (Ler) hybrids in detail. These hybrids have earlier germination and leaf growth than the parents, leading to a larger leaf area at any point in development of the plant. The developing leaves of the hybrids are significantly larger than those of the parents, with consequent greater production of photosynthate and an increased contribution to heterosis. The set of leaves contributing to heterosis changes as the plant develops; the four most recently emerged leaves make the greatest contribution. As a leaf matures, its contribution to heterosis attenuates. While photosynthesis per unit leaf area is unchanged at any stage of development in the hybrid, leaf area is greater and the amount of photosynthate per plant is increased.

Secondary Metabolites, Ferulic Acid and p-Hydroxybenzoic Acid Induced Toxic Effects on Photosynthetic Process in Rumex acetosa L.

“…The electron transport rate (ETR) was calculated from the light-adapted fluorescence parameters as described by Liu [ 28 ]: ETR = PAR × abs × β × ΦPSII where ΦPSII represents the quantum yield of PSII; PAR is the incident photosynthetically active radiation; abs is the leaf absorbance. On average, a healthy leaf of higher plants absorbs ~84% of the incident PAR [ 29 ].…”

“…The electron transport rate (ETR) was calculated from the light-adapted fluorescence parameters as described by Liu [28]:…”

Prior Biological Knowledge Improves Genomic Prediction of Growth-Related Traits in Arabidopsis thaliana

“…As complex traits of study, we focused on photosynthetic light use efficiency of photosystem II (Φ PSII ) and projected leaf area (PLA) in Arabidopsis thaliana . Both of these traits are related, in the sense that the Φ PSII directly illustrates the photosynthetic light use efficiency and can capture the most immediate physiological and regulatory response to varying irradiance levels (Van Rooijen et al, 2015 ), whereas growth in PLA is the net outcome of unit leaf photosynthetic capacity over time (Weraduwage et al, 2015 ; Liu et al, 2020 ).…”

Enhanced photosynthesis and carbohydrate metabolic capability contributes to heterosis of cotton (Gossypium hirsutum) hybrid ‘Huaza Mian H318’ as revealed by genome-wide gene expression analysis

“…In past years, many transcriptome studies have provided insights into the molecular basis of heterosis in different species like rice [8,12], Arabidopsis [13,14] and maize [15,16]. In these studies, a vast number of DEGs associated with different biochemical pathways have been found related to heterosis.…”