Thursday, August 13, 2009

A Story of An Accidental Avocado Grower

Over the past few years, young avocado trees have been sprouting up on my compost heap - mostly from organic seed. The first "yield" presented more than 20 trees! I obviously couldn't leave them where they were. They were such beautiful little trees with such nutritious potential that I also could not bear to pull them up and return them to the heap. I live in South Africa where despite the affluence of some, about half our people live in unacceptable poverty and approximately 1.5 million of our precious children under the age of six years are permanently damaged by malnutrition.

So, I started to transplant the avo saplings into re-used containers and supply them to local community and schools' food gardens. By now, I've lost count of how many avo trees have come to life in this shady, unassuming corner of my garden. It was a sharp realisation for me, how the waste of a family who can afford to buy organic avocados from the supermarket can be turned into good food for the future with hardly any effort at all. Since then, I have been saving seed from much of the organic produce I buy - collecting, sharing and also growing in my small sunny plot.

Here is something special that I love about avocado trees:

The avo is bisexual, that is a single tree does produce male and female flowers.

However, the trees present what my landlord once described as a "conundrum of fecundity" - a biological condition known as 'synchronous dichomagy'. A clumsy phrase for a mysterious process - what happens is that the flowers of different avo cultivars open on 2 subsequent days presenting different sexes.

It works like this: Day 1 - A Hass avocado tree flowers presenting the female stigma ready for pollination but the stamens are all bent away at right angles, young and release no pollen. On Day 2, the flowers open with stigma shrivelled and unresponsive when the stamens are laden with pollen and leaning in a little closer. When the flowers close at the end of the second day they never re-open and so the opportunity for self-pollination of the Hass tree cannot happen even though it's got all the necessary gear.

On the same days, a tree of the Feurte cultivar will open its flowers first with ripe male parts and close; followed by ripe female parts on the second day. So you need a few trees of different cultivars in the same vicinity for the bees to do their work successfully.

This means that the avo tree is structurally bisexual and functionally unisexual. I wondered if this might be because avo trees, like horses, like people, have powerful needs for friends?

Nature is extraordinary...

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