Colin Salter’s new book is a selection of extraordinary electron microscopic images of the plant world around us, including seeds, pollen, fruiting bodies, trees and leaves, flowers, vegetables and fruit
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| Some plants use scent to deter predators or encourage pollinators. The aroma of the scented pelargonium comes from oil held in its leaves and can be released by rubbing or lightly squeezing them: Pelargonium citronellum, seen here with pollen grains, smells of lemons. |
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| Among these characteristically elongated cells of onion tissue, the small coloured bars are calcium oxalate crystals, which also precipitate from over-acidic urine in the human body to form kidney stones. Calcium oxalate has been found in more than a thousand plant families and its function is not entirely clear. It’s assumed that crystals form to absorb excess calcium ingested by the plant. Some plants contain it in toxic quantities, for example rhubarb (leaves, not stem) and Dieffenbachia, which can choke and render speechless those who eat it. |
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| Cannabis resin is produced by the glandular hairs (trichomes, here yellow) on the leaves of the plant. Cannabis sativa, the green cells in this image. Those using the plant recreationally will know that hash comes from this resin, while marijuana is made from the leaves and flowers. |
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| A honeybee leg. Bees have six legs, each covered in tiny hairs ideal for gathering the pollen that the bee needs to feed its larvae. Here you can see, in extreme magnification, that even the hairs have hairs, and these images also give an indication of just how small each grain of pollen must be. Flowers can attract bees in various ways, including scent, the offer of nectar, and the provision of a landing ‘lip’ in the shapes of their petals. |
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| Scented geraniums are not geraniums but pelargoniums – the two families were redefined in the 18th century, having originally all been classed as geraniums. This is a close-up of the leaf of a lemon-scented geranium. The red spheres on some hairs (trichomes) are glands that secrete a scented oil. The scent discourages grazing livestock and attracts pollinators. The yellow sphere is a grain of pollen. |
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| In this enhanced image the ‘mouths’ are the pores on the underside of an elder leaf. The ‘lips’ are the guard cells that expand and contract on either side, closing or opening the pores between them to permit the exchange of gases. During the day, plants give out oxygen as a byproduct of photosynthesis, and they breathe in carbon dioxide, their only source of carbon from which to grow new cells. At night they exhale carbon dioxide and inhale oxygen. Trees are truly the lungs of the planet. |
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| These ‘flowers’ are actually the scale-like hairs (trichomes) on an olive leaf. They have evolved their peculiar shape to minimise moisture loss, a necessary asset in the hot, dry, windy conditions of the Mediterranean countries in which the olive tree, Olea europaea, is grown. At bottom left you can see two slotted leaf pores, which during the day absorb carbon dioxide and release oxygen. The process is reversed at night. |
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| Pollen, which produces the sperm cells necessary for fertilisation of flowering plants, falls into one of two classifications – monocot or dicot (both are seen here). Monocot pollen has a single furrow or pore on its surface, dicots three. Many differences between plants are related to the two types of pollen. |
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| There are several hundred species of Aspergillus fungus, all of them forms of mould found on plants and starchy foods. They reproduce through spores (conidia) at the end of stems (conidophores). A. niger forms almost completely spherical spores radiating outwards from the tip of the stem. |
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| Stripped of the petals and an enclosing ring of male reproductive structures (stamens), this is a striking view of the female reproductive system (pistil) of a rose. Below this crown of the stigma waiting to receive sperm-generating pollen, the rose has many ovaries. After fertilisation they swell to become rosehips, food for birds, which later disperse the seeds from the hips in their faeces. Most garden roses no longer produce hips because they have been bred to have so many petals there isn’t room for pollinating insects. |
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