Responses of Lotus corniculatus to environmental change 3: The sensitivity of phenolic accumulation to growth temperature and light intensity and effects on tissue digestibility

Abstract

Main Conclusion Growth temperature and light intensity are major drivers of phenolic accumulation in Lotus corniculatus resulting in major changes in carbon partitioning which significantly affects tissue digestibility and forage quality.

Responses of Lotus corniculatus to environmental change. 4: Root carbohydrate levels at defoliation and regrowth climatic conditions are major drivers of phenolic content and forage quality

“…In previous experiments (Morris et al 2021) we noticed some anomalous results that suggested that the conditions under which plants were grown affected the levels of tannins accumulated in subsequent vegetative tissues, following harvesting and regrowth. It has also been found that in Arabidopsis the current and prior temperature experience of the mother plant controls seed dormancy through inhibition of proanthocyanidin biosynthesis in fruits, resulting in altered seed coat tannin content (Chen et al 2014).…”

“…Several environmental factors implicated in climate change such as temperature, drought and atmospheric CO 2 concentrations affect the accumulation of plant phenolics in forage legumes. Increases in the accumulation of condensed tannins under controlled high-temperature conditions were found in Lotus pedunculatus (Lees et al 1994), but not in L. corniculatus (Ehike and LeGare 1993;Carter et al 1999) and the optimum temperature and light intensity for L. corniculatus growth and phenolic accumulation has been determined in three clonal genotypes that varied in their tannin content (Morris et al 2021). However, only a few studies have considered the effects of environmentally induced changes in condensed tannins biosynthesis on the nutritional quality of forage legumes.…”

“…Freeze-dried samples (200 mg) were re-hydrated in 2 mL H 2 O for 1 h, and then ground tissue extracted with 70% aqueous methanol. Extracts were concentrated on an activated C18 Sep-Pak column (500 mg, Waters Inc) and bound flavonoids for HPLC analysis eluted with 4 mL 100% methanol, as described previously (Morris et al 2021).…”

“…The sample was concentrated on an activated C18 Sep-Pak column and the hydrolysed flavonoids eluted with 4 mL of MeOH. Flavonoid profiles were obtained by reverse phase HPLC on a µNovapak 8 × 10 C18 RCM cartridge (Waters Inc), and quantified as described previously (Morris et al 2021).…”

“…The extracts were discarded and the pellets dried using a sample concentrator. The pellets were then treated with 10% thioglycolic acid in 2 M HCl (3 mL/50 mg of sample) at 100 °C for 4 h as described previously (Morris et al 2021). The TGA-lignin content of the samples was determined using a PV8700 series UV/Vis spectrophotometer (Philips Scientific and Analytical Equipment) at 280 nm.…”