UV induced visual cues in grasses

Abstract

Grasses are traditionally considered as wind pollinated, however, field observations confirmed frequent insect visits to grass flowers, suggesting insect pollination. Fruit and seed predators inflict heavy losses to cereals and millets during their growth, maturation and storage. The actual factors guiding insects and predators to grass flowers, fruits and seeds are not clear. Here, we report attractive blue fluorescence emissions on grass floral parts such as glumes, lemma, palea, lodicules, staminal filaments, pollens and fruits in ultraviolet (UV) 366 nm, whereas the stigmatic portions were not blue, but red fluorescent. We characterized the blue fluorescent constituent in grass reproductive structures as ferulic acid (FA). Fluorescence spectra of blue-emitting grass floral, seed extracts and isolated FA on excitation at 366 nm showed their emissions at 420–460 nm. We propose these FA-based blue fluorescence emissions in grass reproductive structures as visual cues that attract pollinators, predators and even pests towards them.

Phenolic condensation and facilitation of fluorescent carbon dot formation: a mechanism study

“…17,24 Electrons in the π bond-rich phenolic compounds are often excited by UV light, showing blue photoluminescence. 24 Therefore, we hypothesized that unknown phenolic compounds in the polysaccharide chains, released from the basil seed, might be the origin of the blue photoluminescence.…”

Nutritional properties of the largest bamboo fruit Melocanna baccifera and its ecological significance

“…), which is reported to be in the range of 0.8 to 2.0 mg/g, DW 25 26 . Ferulic acid, known for several biological activities and thus reducing the risk of major diseases such as diabetes, heart disease, cancer etc., is a useful dietary component for human health 25 27 . Owing to its biological significance, several studies on its identification and estimation from various plants were reported in the literature 28 29 30 .…”

Why is the lawn buzzing?

“…A reason for this abiotic relationship are that the flowers are small and drab in appearance rather than showy ( Knuth 1909 ). In contrast, though diminutive and lacking petals and sepals, most graminoid inflorescences are quite colorful when blooming, plus present ultraviolet visual cues that are visible to the bees but cannot be seen by humans ( Baby et al 2013 ). This dichotomy reveals an interesting question: is this just a scale problem for attractiveness?…”