Juvenile Coffee Leaves Acclimated to Low Light Are Unable to Cope with a Moderate Light Increase

Abstract

The understorey origin of coffee trees and the strong plasticity of Coffea arabica leaves in relation to contrasting light environments have been largely shown. The adaptability of coffee leaves to changes in light was tested under controlled conditions by increasing the illumination rate on C. arabica var. Naryelis seedlings acclimated to low light conditions and observing leaf responses at three different developmental stages (juvenile, growing and mature). Only mature leaves proved capable of adapting to new light conditions. In these leaves, different major mechanisms were found to contribute to maintaining a good photosynthetic level. With increased illumination, a high photosynthetic response was conserved thanks to fast nitrogen remobilization, as indicated by SPAD values and the photorespiration rate. Efficient photoprotection was accompanied by a great ability to export sucrose, which prevented excessive inhibition of the Calvin cycle by hexose accumulation. In contrast, in younger leaves, increased illumination caused photodamage, observable even after 9 days of treatment. One major finding was that young coffee leaves rely on the accumulation of chlorogenic acids, powerful antioxidant phenolic compounds, to deal with the accumulation of reactive oxygen species rather than on antioxidant enzymes. Due to a lack of efficient photoprotection, a poor ability to export sucrose and inadequate antioxidant protection, younger leaves seemed to be unable to cope with increased illumination. In these leaves, an absence of induced antioxidant enzyme activity was accompanied, in growing leaves, by an absence of antioxidant synthesis or, in juvenile leaves, inefficient synthesis of flavonoids because located in some epidermis cells. These observations showed that coffee leaves, at the beginning of their development, are not equipped to withstand quick switches to higher light levels. Our results confirm that coffee trees, even selected for full sunlight conditions, remain shade plants possessing leaves able to adapt to higher light levels only when mature.

Dietary Antioxidants in Coffee Leaves: Impact of Botanical Origin and Maturity on Chlorogenic Acids and Xanthones

“…The overall high content of CGAs in young coffee leaves is in agreement with previous studies on different coffee leaf species [11,13,16,17]. Specifically, a high content of 5-CQA followed by 3,5-DiCQA (2 to 8 times lower than 5-CQA) was also found, the sum of which accounts for 82% of the total amount of CGAs present in coffee leaves; this trend had already been reported [13,16,17]. However, in young C. racemosa leaves a lower content 3,5-DiCQA was observed, while 3-CQA and 4-CQA contents were considerably higher than the values obtained for the young leaves of the other coffee species analysed in this study.…”

“…As shown in Table 3, the total CGAs content in young leaves, calculated as the sum of mono-and di-caffeoylquinic acids, varied from 35.732 to 80.836 mg/g of dry matter; C. arabica and C. eugenioides showed the highest content, while C. canephora and C. racemosa showed the lowest content in CGAs, consistent with the trend recently reported by Campa et al [11]. The overall high content of CGAs in young coffee leaves is in agreement with previous studies on different coffee leaf species [11,13,16,17]. Specifically, a high content of 5-CQA followed by 3,5-DiCQA (2 to 8 times lower than 5-CQA) was also found, the sum of which accounts for 82% of the total amount of CGAs present in coffee leaves; this trend had already been reported [13,16,17].…”

“…Metabolic fate and bioavailability of these compounds have been recently investigated, and were found to be absorbed and excreted to a much greater extent than many other dietary flavonoids and phenolic compounds [15]. The high accumulation of CGAs in the coffee leaves of different species has been previously reported, in which 5-caffeoylquinic acid (5-CQA) and 3,5-dicaffeoylquinic acid (3, were found to be the most abundant chlorogenic acids [11,13,16,17].…”

G × E interactions on yield and quality in Coffea arabica: new F1 hybrids outperform American cultivars

“…Quantitative analyses were carried out on a HPLC system (Shimadzu LC-20, Tokyo, Japan) as described earlier (Campa et al 2017). Extracts (10 ll) were analyzed at a flow rate of 0.6 ml/min using an Eclipse XDB C18 (3.5 lm) column (100 mm 9 4.6 mm, Agilent) and an elution system composed of solvents B (H 2 O/MeOH/acetic acid, 5:90:5 v/v/v) and A (water/acetic acid, 98:2, v/v).…”

Metabolic processes in the leaves of the genus tilia l. Plants as a marker of adaptation to climatic conditions of steppe dnieper

“…Об'єктами досліджень слугували 5 видів і один гібрид роду Tilia L., з яких 1 аборигенний -Tilia cordata Mill., 5 Оскільки світло є основним джерелом життя для рослин, вони мають багаторівневу систему оптимізації захоплення енергії світла, необхідної для оптимального фотосинтезу незалежно від інтенсивності світла (Campa C et al, 2017). Проте, надмір-не опромінення може призвести до енергетичного дисбалансу та незворотного пошкодження основних компонентів білкового комплексу фотосистеми ІІ.…”