Evidence for a photoprotective function of low‐temperature‐induced anthocyanin accumulation in apple and pear peel

Abstract

The light requirement and low-temperature stimulation of anthocyanin synthesis in peel of apple (Malus domestica) and pears (Pyrus communis) and the presence of anthocyanins in immature fruits are not congruent with a visual function in dispersal. We hypothesized that anthocyanins afford photoprotection to peel during low-temperature-induced light stress and that the protection is not a fortuitous side-effect of light absorption by anthocyanin. The extent of photoinhibition at harvest and after light stress treatment in pear cultivars differing in redness decreased with increasing red color on the sun-exposed sides of fruits. Green-shaded sides of the pears showed comparable levels of photoinhibition indicating that pears did not differ in their inherent photosensitivity. Apple and pear peel show considerable short-term fluctuation in redness in response to temperature, with red color increasing rapidly in response to low temperature and just as quickly fading in response to high temperature. Briefly, shading pears and apples during cold conditions for 2 days reduced the accumulation of anthocyanin and increased the photosensitivity of peel. Subsequent shading during warm conditions did not affect the accumulation of anthocyanin or the photosensitivity of peel indicating that the response at low temperature was not due to shade adaptation. The assessment of photosystem II (PSII) efficiency and quenching of chlorophyll fluorescence between 16 and 40 degrees C indicated that 'Forelle' pear peel was particularly sensitive to photostress at low temperature. The photosynthetic system in mature 'Forelle' leaves was comparatively much less sensitive to light stress at low temperature. Results support the view that anthocyanins are adaptable light screens deployed to modulate light absorption in sensitive tissues such as fruit peel in response to environmental triggers such as cold front snaps.

Environmental effects on fruit composition of cloudberry/bakeapple (Rubus chamaemorusL.) grown in southern Labrador, Canada

“…Martinussen et al (2010) indicated that the total anthocyanins in bakeapple were negatively related to high temperature, similar to studies in apple and pear peel (Faragher 1983;Steyn et al 2009;Martinussen et al 2010). On the other hand, reports on anthocyanin content in pomegranate have shown decreasing anthocyanin content with rising temperature (Borochov-Neori et al 2011).…”

Loss of ferulate 5-hydroxylase leads to Mediator-dependent inhibition of soluble phenylpropanoid biosynthesis in Arabidopsis

“…They are widely distributed among the vascular plants, where they play important roles in photoprotection, plant-pollinator interactions, and responses to abiotic stress (Spaethe et al, 2001;Steyn et al, 2009;Schenke et al, 2011;Yuan et al, 2013). Variations in the spectral properties of different anthocyanins primarily arise from a small number of ring modifications on the chromophore itself, together with the combinatorial addition of peripheral moieties by various glycosyltransferases and acyltransferases (Mol et al, 1998).…”

Role of Temperature and Soil Moisture Conditions on Flavonoid Production and Biosynthesis-Related Genes in Ginkgo (Ginkgo biloba L.) Leaves

“…The metabolism of flavonoids follows a complex pathway, and some environmental factors such as temperature, water status, light condition, and nitrogen all have been demonstrated to affect flavonoids accumulation [22][23][24][25]. The present study demonstrated that lower temperature and to a lesser extent lower soil moisture content is favourable to flavonoid accumulation in Ginkgo leaves, and more specifically W2T1 and W3T1 treatments produced the highest total flavonoid content (Table 3).…”