Tagged: chlorophyll fluorescence





Papaya genotypes

Photosynthetic capacity, respiration and growth of two papaya genotypes with different chlorophyll concentrations

Papaya is the most economically important species within the Caricaceae family and it is widely cultivated not only for fruit consumption, but also for the proteolytic enzyme papain, which has several commercial and medical uses. The Golden genotype of papaya (Carica papaya), named for its yellowish leaves, produces fruits very much appreciated by consumers worldwide. However, its growth and yield are considerably lower than those of other genotypes, such as ‘Sunrise Solo’, which has intensely green leaves. Previous work has shown that Golden had similar CO2 uptake rates to ‘Sunrise Solo’, which suggests that physiological processes other than photosynthesis are likely...

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Miscanthus under the sun

Physiological basis of miscanthus chilling tolerance

The biomass crop Miscanthus x giganteus has a high chilling tolerance for a C4 plant, allowing for a longer productive growing season in temperate climates. The understanding of the mechanisms that underlie chilling tolerance in the genus Miscanthus is limited, but could help breeding adapted varieties and aid the development of cold tolerant C4 crops. Fonteyne et al. study chilling related traits in five species and hybrid genotypes under natural conditions in the field. The two most chilling tolerant genotypes are distinct from the two chilling sensitive genotypes in a number of the biochemical traits measured, while M. x giganteus...

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Different types of rice tiller responses to nitrogen

Tillering is an important agronomic trait for rice population quality and grain production. In a recent study published in AoB PLANTS, Wang et al. found that nitrogen fertilizer application increased the number of rice tillers, but not every tiller contributed equally to the overall yield. Heterogeneity in tiller yield of rice increased with increasing nitrogen levels. Typically, late emerging tillers contributed less to the grain yield. Under high nitrogen conditions, most of the nutrients were retained in the straw of late emerging tillers; these tillers have high transport efficiency in vascular bundles, but there is less time for nutrients to...

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Clonal integration facilitates the colonization of drought environments by plant invaders

Identifying the mechanisms underlying the process of biological invasions is a crucial objective for ecological research. In a study published in AoB PLANTS, Lechuga-Lago et al. examined the role of clonal integration in the colonization of a water-stressed environment by an aggressive invader. Their results demonstrate that the effects of clonal integration confer a benefit to clonal plants for the colonization of stressful environments, and therefore should be considered as a mechanism to explain the success of some clonal invaders. Understanding the influence of clonal life-history traits in plant invasions seems key for predicting future invasion scenarios and for devising...

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Trifolium pratense

Role of polyphenol oxidase in oxidative stress in leaves

Polyphenol oxidases (PPOs) catalyse the oxidation of monophenols and/or o-diphenols to highly reactive o-quinones, which in turn interact with oxygen and proteins to form reactive oxygen species (ROS) and typical brown-pigmented complexes. Hence PPOs can affect local levels of oxygen and ROS. Although the currently known substrates are located in the vacuole, the enzyme is targeted to the thylakoid lumen, suggesting a role for PPOs in photosynthesis. Boeckx et al. subject wild-type red clover (Trifolium pratense) and a low-PPO mutant to either environmental stress (cold and high light) or oxidative stress generated via methyl viologen, and find that PPO activity...

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Photosynthetic thermotolerance and leaf traits

Photosynthetic thermotolerance and leaf traits

Little is known about photosynthetic thermotolerance (PT) of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Zhang et al. use the temperature-dependent increase in minimum fluorescence to assess PT for a total of 24 woody species differing in leaf flushing time in a valley-type savanna in south-west China. They find that PT is positively associated with leaf life span and foliar calcium concentration but is independent of leaf mass per unit area. The current maximum leaf temperature during extreme heat stress (44.3 °C) is close to the critical temperature of photosystem II (45.2 °C), and thus...

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Photosynthetic costs of foliar variegation in Begonia

Photosynthetic costs of foliar variegation in Begonia

Foliar variegation is often assumed to be due to lack of chlorophyll or the presence of special pigments in sections of a leaf, but it can also result from leaf structural variation. Sheue et al. show that naturally occurring foliar variegation in six species and one cultivar of Begonia is due to air spaces above the chlorenchyma, situated either below the adaxial epidermis or below the adaxial water-storage tissue. Photosynthetic functioning is retained in the light areas of the leaves, and these areas do not include primary veins, potentially limiting the costs of variegation.

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Nepenthes talangensis - Pitcher plant

Carnivorous plants prefer to kill in broad daylight

I owe thanks to Dr Andrej Pavlovič for being a patient guinea pig with my first press-release (you can find it on Science Daily) and to Lizzie Shannon-Little at OUP for helping put it out. It’s good timing because another paper by Pavlovič on carnivorous plants and photosynthesis is now a year old – which makes it free to access. Feeding enhances photosynthetic efficiency in the carnivorous pitcher plant Nepenthes talangensis is a good partner paper to Trap closure and prey retention in Venus flytrap (Dionaea muscipula) temporarily reduces photosynthesis and stimulates respiration. They both cover the costs of carnivory....

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