Thursday, October 29, 2009

Family comes first, among plants too


Caring and sharing within the family are traits we associate with humans and animals. But a startling new study has found that for plants too, “blood is thicker than water”.

They cannot speak, move, see or hear, but plants apparently recognize family and respect their space, says the study. It was conducted by scientist Harsh Bais and his colleagues at the University of Delaware. “At least 3,000 plants were researched and it took us three years,” Bais tells Eureka via email. He says that Arabidopsis thaliana, a member of the mustard family and widely used as a model organism in plant biology, behaves nicely to ‘siblings’ – i.e. plants grown from seeds from the same ‘mother’. Interestingly, it is intensely competitive with strangers.

Fascinating and unbelievable though this may be, talk of plants and their ‘siblings’ is not new. In 2007, a team of Canadian researchers showed that plants can indeed identify ‘siblings’. But Bais and his team went a step further by discovering how a plant recognizes its ‘brother’ or ‘sister’, namely by root secretions. When the plant sensed unfamiliar root secretions, it began competing by growing more roots in order to absorb more of the soil’s mineral nutrients and water. But with ‘siblings’, they threw out fewer roots. When Bais treated
a plant to a chemical that blocked the secretions, it seemed to lose its discriminatory sense. Clearly, there is something in these secretions that tells a plant whether it is related to others around it.

Strangers planted next to each other are often shorter, it noted, because so much of their energy is concentrated on root growth. “It’s possible that when kin are grown together, they may balance their nutrient uptake,” says Bais.

Harsh Bais with a PhD student at the University of Delaware


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