Term 2 Notes On The Secret Life Of Plants: Survival Flashcards
Survival in the desert: the Quiver tree and Confidium Namibia
Quiver tree -Can self amputate - cut off a leaf rosette and seal the stump preventing the branch from growing leaves again.
The tree survives with less leaves in poor conditions and puts out new shoots when conditions improve.
Confidium - new leaves reside under old ones awaiting rain, then the leaves peel back revealing fused fleshy new leaves beneath and purple flowers sprout
Survival in the desert: Sowado Cactus Arizona and New Mexico
Each can hold several tonnes of liquid, complete lack of leaves the stem photosynthesises, pores are protected in grooves and these pleats allow stems to expand/contract according to water availablity.
Spines protect them from herbivores
Survival in the desert: window plant
Only the transparent top is visible above the sand allowing light to pass through, transmitted by a series of crystals down to the bottom of the leaf where chlorophyll is present.
This prevents detection by herbivores whilst still making photosynthesis possible
Survival in the desert
Desert plants survive the hottest part of the summer below ground as bulbs or tubers - however this puts them at risk of consumption by mole rats which may eat the bulb directly or collect and store them in larders.
This can be beneficial though - not all stored bulbs are used by the mole rats and some larders are abandoned so the bulbs can sprout there and benefit from a new location.
Other desert plants are very short lived - living just a few weeks and putting all their energy into seeds able to await the next rainfall for upto 20 years. They rapidly respond to rain to germinate and flower.
Surviving in the wettest places on earth : carnivorous plants
Where it rains almost every day and sometimes continuosly for days on end.
E.g. Mt Roraima in south America on top of a sandstone plateau 9000ft high 5 miles across surrounded by vertical cliffs.
The main problem for plants here is a lack of nutrients due to rushing streams washing them all away. Plants can only grow where sediment accumulates so must augment their food e.g. by being carnivorous - like pitcher plants.
Bladderwort hunts in Roraima’s bromeliads spreading its tendrils forming ‘bladders’ tiny capsules containing glands that extract water creating a partial vacuum. Each bladder has a door fringed with bristles. If prey e.g. mosquito larvae touch this trigger then the door implodes swinging prey inside. Each bladder is ready for new prey after just 2 hours.
Sundews have sticky droplets that attract and trap insects, once stuck hairs move swiftly (180° in less than a minute) to infurl the insect
Accessing light: Giant Amazonian water Lily in river swamps
Here access to light is the limiting factor, plants must command the surface
E.g. Giant Amazon water lily
Spiny leaves protect them from fish
Huge surface area is maintained by a lattice of airfilled struts, crinkles on surface flatten as the leaf expands to full size
The edges of the leaves are turned up to push aside competitors
- each leaf has a 6ft diameter and below them almost no plants can grow
- birds like lily trotters spend their whole lives walking across the leaf surfaces collecting insects
Pollination control: Amazonian water Lily
The giant lily flowers are 1m across.
They bloom white in the evening with a strong scent, close for the whole next day turning pink on the second evening they open again and then close a final time.
Why? This avoids self pollination
How? The perfume of the first evening attracts beetles bringing pollen from other lilies, then the lily closes trapping the beetles for 24 hours and releasing them the following evening. During their stay the beetles pollinate the flower and are coated in this flowers pollen, the red odourless flower is no longer attractive to the beetles so they leave taking the lilies pollen to other flowers.
Surviving on rocky coasts
No flowering plants survive here due to the pounding waves and surging currents but algae do. Their stems are flexible supported by water and hold fasts grip so tightly to rocks that if ripped up by the current the rock is more likely to break than the plant.
Gas filled floats keep their blade-like ‘leaves’ afloat to catch surface light. They can grow in waters up to 100ft deep but as they flex in the current their total length can be many times that - one specie up to 300ft long (kelp forests)
Surviving deep open water
In the open ocean single cell algae thrive. There is enough light and nutrients and the temperature is stable
Basis of all life is in the water.
Floating algae in the sea provide more O2 than all land based plants combined
