The price of Wehrhaftigkeit

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Speed ​​is not everything. Especially not when suffer the ability to defend themselves against enemies. Ecologists and plant biologists of the University of Zurich demonstrate together with American researchers that fast plant growth is at the expense of the natural defense mechanisms. The new findings are the trimmed for high yield crops and their weak pest resistance significance.

Plants are on the menu of many insects and mammals. As a protection against predators, they developed during evolution complex defense mechanisms: spines, thorns, leaf hairs and a number of toxic chemical substances. For decades, it is discussed whether the training of defense mechanisms is associated with costs for the plants. Now have ecologists and plant biologists of the University of Zurich together with their American colleagues in an article published in the Proceedings of the Royal Society article these costs with a new method for accurately.

For their investigations the researchers planted various so-called knock-out mutants of the same genotype of the model plant Arabidopsis thaliana - "knockout mutants" because they have one or more specific genes were selectively inhibited, allowing insights into their function. The researchers then harvested at regular intervals a portion of the plant to determine the biomass growth over the whole plant life. "Mutants with suppressed defense mechanisms showed an increased growth rate," Tobias Züst says about the results of his study. But the rapid growth has its price: aphids reproduce faster on them than on plants with intact defense mechanisms. This is due to that the pests of fast growing plants at the same time more resources are available than in slow-growing plants.

The study shows that natural pest resistance is often not compatible with fast growth. This situation is in terms of agricultural crops of major importance: crops have been mostly bred for high yield and, therefore, have very low natural resistance to herbivores, consequentially requiring high input of insecticides.

Picture: Fotolia