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Mutualisms are common in nature. In Fiji, a species of ant selects, disperses and fertilizes an epiphytic plant in an exclusive symbiosis. This represents a novel example of plant farming by ants.
The authors identify novel NEGATIVE GRAVITROPIC RESPONSE OF ROOTS genes in Medicago and Arabidopsis. Mutants display a spectacular phenotype: gravity is still perceived, but the direction of growth is reversed: roots always grow upwards.
Photorespiration is a major light-dependent metabolic pathway that consumes O2 and produces CO2. Quantitative isotopic labelling experiments with sunflower leaves suggest that the O2/CO2 stoichiometric coefficient of photorespiration at the leaf level is very close to 2 under typical photorespiratory conditions.
