Effect of Colored Shadecloth on the Quality and Yield of Lettuce and Snapdragon

Abstract

<jats:p>Colored shadecloths are used in the production of vegetable, fruit, and ornamental crops to manipulate the light spectrum and to induce specific plant physiological responses. The influence of three colored shadecloths (red, blue, and black) with 50% shade and a no-shade control on the production of two lettuce (<jats:italic>Lactuca sativa</jats:italic>) cultivars [Two Star (green-leaf) and New Red Fire (red-leaf)] and snapdragon (<jats:italic>Antirrhinum majus</jats:italic>) was investigated. Use of shadecloth increased plant growth indices of lettuce and total length of snapdragon flower stems (at the first harvest) compared with no-shade control. Red shadecloth resulted in longer flower stems of snapdragon (at the second harvest) than black and blue shadecloths and no-shade control. However, shadecloth delayed blooming of snapdragon for 1 week compared with no-shade control. Stomatal conductance (<jats:italic>g</jats:italic><jats:sub>s</jats:sub>) and leaf transpiration rate of both lettuce cultivars and photosynthetic rate and transpiration rate of snapdragon were decreased in response to shadecloth treatments. All shadecloths decreased health beneficial flavonoids (luteolin/quercetin glucuronide and quercetin malonyl concentrations for both lettuce cultivars and cyanidin glucoside in red-leaf lettuce). The two lettuce cultivars varied in their phenolic compounds, with the green-leaf ‘Two Star’ having higher quercetin glucoside and caftaric acid than red-leaf ‘New Red Fire’, whereas ‘New Red Fire’ had higher concentrations of chlorogenic acid, luteolin/quercetin glucuronide, and quercetin malonyl. Shadecloths reduced substrate temperature and photosynthetically active radiation (<jats:italic>PAR</jats:italic>) to about half of full sunlight compared with no-shade control, which may have contributed to reduced <jats:italic>g</jats:italic><jats:sub>s</jats:sub> and leaf transpiration (for lettuce and snapdragon), decreased phenolic compounds in lettuce, and delayed flowering of snapdragon.</jats:p>

Effect of High Tunnel Coverings on Antioxidants of Breaker and Light Red Tomatoes at Harvest and during Ripening

“…CHS is the first step in the flavonoid biosynthesis pathway [31] and previous studies have found that both blue light and UV-A light enhance the response of CHS to UV-B synergistically [28,32]. It has been shown that full-spectrum, solar radiation can increase the amounts of certain phenolic compounds, such as flavonoids and phenolic acids due to photo-oxidative stress [30,[33][34][35][36]. However, responses are crop and species specific, and it has been suggested that solar UV-B may be insufficient to promote flavonoid production [37], therefore, supplemental radiation may be needed for increased accumulation.…”

Bioactive constituents of red and green lettuce grown under colour shade nets

“…Photo-selective, coloured, shade nets provide diverse mixtures of natural, unmodified light and scattered, spectrally modified light (Ilić and Fallik, 2017). Spectral modification promotes physiological responses which affects productivity and quality (Li et al, 2017). Accumulation of phytochemicals depends on many factors, such as light quality and quantity, type of varieties or cultivars, growing season and metabolic factors (Simakumar and Jifon, 2017).…”

Redes fotosseletivas na agricultura

“…Inicialmente, as redes fotosseletivas eram brancas, pretas ou do tipo Aluminet ® (Ganelevin, 2006;Li et al, 2017). No ano de 1996, redes coloridas como vermelha, amarela, azul e pérola (ChromatiNet ® ) foram introduzidas para absorver e alterar, o espectro e a Research, Society and Development, v. 9, n. 8, e590985921, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i8.5921 radiação que atinge às plantas, devido a uma parceria entre pesquisadores e a indústria (Ganelevin, 2006;Manja & Aoun, 2019).…”