Plants and Light Manipulation: The Integrated Mineral System in Okra Leaves

Abstract

Calcium oxalate and silica minerals are common components of a variety of plant leaves. These minerals are found at different locations within the leaf, and there is little conclusive evidence about the functions they perform. Here tools are used from the fields of biology, optics, and imaging to investigate the distributions of calcium oxalate, silica minerals, and chloroplasts in okra leaves, in relation to their functions. A correlative approach is developed to simultaneously visualize calcium oxalates, silica minerals, chloroplasts, and leaf soft tissue in 3D without affecting the minerals or the organic components. This method shows that in okra leaves silica and calcium oxalates, together with chloroplasts, form a complex system with a highly regulated relative distribution. This distribution points to a significant role of oxalate and silica minerals to synergistically optimize the light regime in the leaf. The authors also show directly that the light scattered by the calcium oxalate crystals is utilized for photosynthesis, and that the ultraviolet component of light passing through silica bodies, is absorbed. This study thus demonstrates that calcium oxalates increase the illumination level into the underlying tissue by scattering the incoming light, and silica reduces the amount of UV radiation entering the tissue.

Mineral Deposits in Ficus Leaves: Morphologies and Locations in Relation to Function

“…In many cases, the cystolith is connected to the outer cell wall through an internal silica stalk that helps to stabilize the ACC phase (Setoguchi et al, 1989;Sugimura et al, 1999;Gal et al, 2010Gal et al, , 2012b. It has been demonstrated that, in the palisade mesophylls of Ficus microcarpa, Morus alba, Abelmoschus esculentus (okra), and Peperomia obtusifolia, cystoliths or calcium oxalates function as light scatterers, increasing the leaf photosynthetic yield (Kuo-Huang et al, 2007;Detmann et al, 2012;Gal et al, 2012a;Horner, 2012;Horner et al, 2012;Pierantoni et al, 2017). Furthermore, in okra, the locations of calcium oxalate and silica deposits are not independent.…”

Cystoliths inFicusleaves: increasing carbon fixation in saturating light by light scattering off a mineral substrate

“…Notably, both of these properties were found to be highly correlated with one another, reporting on the wasted portion of absorbed light and therefore serving as an inverse proxy for the efficiency of photosynthesis (Govindjee 1986, Papageorgiou 2007). Measurement of chlorophyll fluorescence has the advantage of accessing local differences in fluorescence with micrometer resolution, and was used in two follow-up studies on various Ficus species (Pierantoni et al 2017, 2018). Microfluorimetry can thus be used to differentiate between the effects of irradiance on minerals and on the surrounding tissue.…”

Foliar epidermal anatomy of some selected wild edible fruits of Pakistan using light microscopy and scanning electron microscopy

“…Scanning electron microscopy (SEM) has brought great revolution in the diversified fields of biological sciences and other disciplines during the last few decades (Esfandani‐Bozchaloyi & Zaman, , Luqman et al, ; Pierantoni et al, ; Ullah et al, Ullah et al, , Ullah et al, ).…”

“…Morphological and anatomical significance of wild fruits cannot be ignored because they have important characters that differentiate them from cultivated fruits and this information could be helpful in correct identification of the species, which is important in plant breeding techniques to improve the fruit production and taste for the growing population. Anticlinal wall pattern, stomata type, and stomatal aperture and orientation are the taxonomically useful cuticular features of plants which are helpful to distinguish a plant from other related taxa within a family (Kadiri, Asekun, & Olowokudejo, 2019 during the last few decades (Esfandani-Bozchaloyi & Zaman, 2018, Luqman et al, 2019Pierantoni et al, 2017;.…”