#56 - Feb 2022 - Garden Stuff - © Sandy Lang - slang@xtra.co.nz
PLANT MOBILITYFebruary/March: Late summer/early autumn. Garden tatty as summer growth, wind, drought and rain take their toll. Late-summer pruning: •remove unwanted growth, •remove dead/dying shoots (more easily identified when still in leaf). Also, •tie up and •redirect growth you want to keep, to form the skeleton of next year’s plant.
Immobile: Unlike us legged creatures, plants can’t move after the seed has fallen. For better or worse they must live out their whole lives in that same spot. What if the spot is unideal? To some extent plants can adapt to unideal situations.
The one chance plants get to relocate is between generations. For this the daughter plant (seed) should not fall too near its mother plant (to obtain a change in circumstances), nor too near its siblings (to minimise sibling competition).
Remote generations: Seeds have evolved many ways to move away from their mother plants before deposition. While a seed can’t choose where it lands, it can choose to travel as far as possible before it lands. By producing large numbers of seeds and by dispersing these randomly over a large area, plants can rapidly colonise a new region and maximise their chances of survival across generations. Some seeds will land in good spots, others in bad spots. ‘A sower went out to sow his seed: and as he sowed…’ Luke 8:5.
Seed dispersal: By: •Wind (dandelion, thistle, 10 km; sycamore, pine, tumbleweed, 500 m). •Water (coconut, sea, 1000s km). •Furry animals (burrs in fur, bindii in feet, 100 km). •Birds, bats (soft fruits, seeds in poo, 100 km). •Small vertebrates (nuts, seeds to nests, 100 m).
In Garden Stuff #27 (see www.mulchpile.org) I emphasised the importance of sex in plants and animals to create genetic diversity. A species’ adaptation and survival depend on genetic diversity. But how can a plant have sex with a distant plant if neither can move?
Remote sex: The female reproductive unit (egg cell) remains in the ovary of the parent plant, but the male reproductive units (pollen grains) are produced in very large numbers in the anthers from whence they are liberated. It is important the pollen is: •highly mobile (tiny) and •lands in the right place (stigma), •on a female flower of •the same species. That's a tall order...
Pollen dispersal: Random dispersal by: •Wind (pine, the grasses, grapevine, 100 km) - just imagine the wastage of undirected pollen dispersal (but any hayfever sufferer is aware of what huge numbers can do). Also, more directed pollen dispersal which uses animals as carriers: •Insects (bees, bumble bees, flies, beetles, 10 km). •Small vertebrates (birds, bats, 10 km). Google Coevolution. ___________________________________
PLANT MOBILITYFebruary/March: Late summer/early autumn. Garden tatty as summer growth, wind, drought and rain take their toll. Late-summer pruning: •remove unwanted growth, •remove dead/dying shoots (more easily identified when still in leaf). Also, •tie up and •redirect growth you want to keep, to form the skeleton of next year’s plant.
Immobile: Unlike us legged creatures, plants can’t move after the seed has fallen. For better or worse they must live out their whole lives in that same spot. What if the spot is unideal? To some extent plants can adapt to unideal situations.
The one chance plants get to relocate is between generations. For this the daughter plant (seed) should not fall too near its mother plant (to obtain a change in circumstances), nor too near its siblings (to minimise sibling competition).
Remote generations: Seeds have evolved many ways to move away from their mother plants before deposition. While a seed can’t choose where it lands, it can choose to travel as far as possible before it lands. By producing large numbers of seeds and by dispersing these randomly over a large area, plants can rapidly colonise a new region and maximise their chances of survival across generations. Some seeds will land in good spots, others in bad spots. ‘A sower went out to sow his seed: and as he sowed…’ Luke 8:5.
Seed dispersal: By: •Wind (dandelion, thistle, 10 km; sycamore, pine, tumbleweed, 500 m). •Water (coconut, sea, 1000s km). •Furry animals (burrs in fur, bindii in feet, 100 km). •Birds, bats (soft fruits, seeds in poo, 100 km). •Small vertebrates (nuts, seeds to nests, 100 m).
In Garden Stuff #27 (see www.mulchpile.org) I emphasised the importance of sex in plants and animals to create genetic diversity. A species’ adaptation and survival depend on genetic diversity. But how can a plant have sex with a distant plant if neither can move?
Remote sex: The female reproductive unit (egg cell) remains in the ovary of the parent plant, but the male reproductive units (pollen grains) are produced in very large numbers in the anthers from whence they are liberated. It is important the pollen is: •highly mobile (tiny) and •lands in the right place (stigma), •on a female flower of •the same species. That's a tall order...
Pollen dispersal: Random dispersal by: •Wind (pine, the grasses, grapevine, 100 km) - just imagine the wastage of undirected pollen dispersal (but any hayfever sufferer is aware of what huge numbers can do). Also, more directed pollen dispersal which uses animals as carriers: •Insects (bees, bumble bees, flies, beetles, 10 km). •Small vertebrates (birds, bats, 10 km). Google Coevolution. ___________________________________