What’s On The Show Today?Find out the components of fertilisers, grow a love apple in Vegetable Heroes, all about no –dig gardening in part 2 of starting from scratch in this new series in Design Elements, plus a ray of sunshine in Talking Flowers.
WILDLIFE IN FOCUSSula leucogaster Brown Booby
It’s not just seagulls that frequent our shores but Australia is home to one of the world’s most spectacular divers.
I'm talking with Dr Holly Parsons, Manager of www.birdsinbackyards.org.au
Let’s find out about it .
Their flight is fairly distinctive - alternating between a few flaps and a glide, often low over the water.
Did you know that the Brown Booby can accelerate up to 90 kph?
The booby’s sleek and velvety profile serves a double purpose, for not only is it aerodynamically adapted for speed in the air, but it is also aquadynamically adapted for swiftly penetrating the surface waters of the ocean.
|Brown Boobies on top of piers|
The reason this topic is being mentioned is because although gardeners realise that pollination is vital in a plants reproductive cycle so that seeds, fruit or veg is formed.
The problem is though, gardeners often struggle with the question,
“ why haven’t I got fruit on my zucchini plant, when there’s plenty of flowers, and plenty of bees buzzing around.?
Substitute what fruit or vegetable that you’ve had trouble with getting it to fruit in place of that zucchini.
|Bee on flower|
This year, though, there’s plenty of passionfruit.
So what happened?
First , let’s start with what is pollination
To simplify things, during plant reproduction, pollination is when pollen grains move from the anther of one flower to the stigma of another flower.
|Regular flower part|
|Silk of Sweet Corn|
- Insects can pollinate flowers, and so can the wind.
- Insect-pollinated flowers are different in structure from wind-pollinated flowers.
- Insect pollinated flowers are large and brightly coloured, mostly scented and with nectar.
- All of this is needed to attract the insects.
- The pollen grains are sticky or spiky so that they stick to the insect good and proper.
- Inside the flower, the anthers are stiff and firmly attached so that they remain in place when an insect brushes past.
- The stigma, usually higher than the anther, has a stick surface to which pollen grains attach themselves when an insect brushes past.
- Wind pollinated flowers are often small, dull green or brown with no scent or nectar.
- The flower usually has hundreds of thousands of pollen grains that are smooth and light so that they can easily be carried by wind without clumping together.
- Anthers are outside the flower, and usually loos and long. All the better to easily release pollen grains.
Grass flower parts.
- The stigma is also outside the flower and looks more like a feather duster so it can more easily catch those drifting light pollen grains.
- That’s important to remember if you think about sweet corn which is from the grass family and therefore wind pollinated.
- When it comes to insect pollinated flowers, the different heights of the anther and the stigma is designed by nature so that the plant avoids self-pollination or inbreeding.
Did you know that most plants are hermaphrodites because they have both male and female parts in the same flower?
Even corn is a hermaphrodite but because it’s in the grass family, it has separate male and female flowers on the same plant rather than on different plants like Spinach.
In Corn the male flowers are position above the female flowers, ie, silks, below containing the ears.
The flowers are self-compatible with pollen being spread by wind and not insects.
This means it’s subject to inbreeding depression, so seed saves need to replant at least a hundred plants for true to type maintenance.
Pumpkin and zucchini is another variation in that the separate male and female flowers are on the same plant and are self –compatible just like corn, but relying on insects.
Without insects to transfer the pollen there would be no fruit.
Botanists call the flowers of tomatoes, perfect flowers because they have male and female flowers within the same flower.
That means they are self-pollinating and don’t need cross-pollination by wind, birds or insects.
Now to that sticky question, “why isn’t my plant fruiting?”
- There’s plenty of flowers and insects but still no fruit.
- Weather conditions are key factors in successful pollination.
- High humidity creates sticky pollen which does not transfer well.
- Plants in the cucurbit family rely on honeybees for pollination, and honeybees do not fly in cool, cloudy weather.
- As temperatures reach the high 20's and the humidity level is also high. the success rate for pollination declines.
- A heat wave in the thirties, will result in poor if any, pollination.
- When the weather is very hot and dry with temperatures over 29 C, the pollen becomes very dry and isn't easily transferred.
|Passionfruit flower with fruit in background.|
- Another factor is plant stress:
- In nature when a plant is under stress, it will not produce fruit.
- Or, it will abort existing fruit.
- It’s a survival mechanism, allowing a plant to focus upon survival first.
- That stress is caused by:
- Water Too little or too much water.
- The Cure: Keep soil consistently moist, not wet and not dry.
- Soil pH imbalance pH levels are too high, or too low.
And if you don’t have enough insects like bees visiting your garden, you know what to do, plant more bee and other insect attracting plants like Borage and Alyssum around your garden.
AND THAT WAS OUR VEGETABLE HERO SEGMENT FOR TODAY!
- · Patience
- · Love of Variety
- · Elegance
- · Daintiness
- · Afterthought (or the wish things happened differently).
- · Purple asters symbolize wisdom and royalty, and are the most popular colour.
- · White asters symbolize purity and innocence.
- · Red asters symbolize undying devotion.
- · Pink asters symbolize sensitivity and love.