Naked tomatoes talk about...the chives?

This 'Sweet 100' grafted tomato plant went into the glasshouse

in the first week of September and had its first ripe tomatoes

by the last week of November. 

Was this due to its friendly underground relationship 

with the basil, nasturtiums and lettuce nearby?

Organic growers have long known of the importance of soil organisms like
mycorrhizae  (the thin threads of fungi that connect to the roots of plants) in stimulating growth and protecting the health of individual plants. Mycorrhizae also connect plants to each other below ground. This can occur over remarkable distances, such as a whole forest, where one tree can be linked to dozens of others, over distances as great as 30 metres.

Why are mycorrhizae important? They transport water and minerals to the roots of plants, in exchange for some nutrients. Their role in the transport of phosphorus, a key element for plant growth, is especially important. Plants growing in soil rich in mycorrhizae grow better than plants in soil without them. Given the damage that artificial fertilisers can do to the environment (and the fact that many of them are derived from non-renewable resources such as natural gas and phosphate rock) knowing more about how mycorrhizae naturally contribute to plant growth and health is very useful.

It now seems that this is not just due to better mineral uptake, but also because the mycorrhizae actively communicate 'messages' between plants, enabling them to adjust to environmental stresses better. In an experiment conducted by Ren Sen Zeng and colleagues at the South China Agricultural College in Guangzhou (reported by Michael Marshall in New Scientist, 13 November 2010, p. 14) tomato plants were grown in pairs in pots. Some were allowed to develop mycorrhizal networks between their roots and others were prevented from doing so. Then one plant in each pot was sprayed with a blight-causing fungus. Plants which shared a mycorrhizal network were less likely to develop the blight. If they got it, their symptoms were less severe, and they were also more likely to activate defensive genes and enzymes.

The researchers concluded that the plants were signalling to each other, using the mycorrhizae as their 'internet'. No experiments outside the lab have been done yet to check if these results hold for the real world (or whether something else could be going on) but it is a very interesting and promising line of enquiry. The science of understanding nature well enough to nudge it in the direction desired by humans, with almost no expenditure of energy or money, and no negative environmental consequences, is much more exciting to me than twisting nature to human ends using lots of energy and finance, and compromising the natural environment in the process.

 These tomatoes were planted out on October 24, 

and photographed a month later.

I am sure they are chatting among themselves,

as they are growing really well.