Letters in 2019

Obligate parasitic plant Striga hermonthica is insensitive to abscisic acid because of a mutation in a key protein phosphatase 2C in the hormone signalling pathway. The parasite maintainskeeps its stomata open, even under drought stress, to draw water and nutrients from its host.

It is unknown how plant cell polarities are connected to organismal axes. A SOSEKI protein is found to integrate apical–basal and radial organismal axes to localize to polar cell edges independent of tissue context, but requiring cell wall integrity.

In polyploid wheat, overexpression of abscisic acid receptor pyrabactin resistance 1-like 4 increases water-use efficiency just like in model plants, confirming the biotechnological potential of this strategy in crops.

A quintuple mutant—affected in gibberellin signalling, as well as showing faster and enhanced growth compared to the wild type—is used as a tool to understand the physiological basis of source–sink coordination.

Ecosystem services from forests depend on the species therein, but the type of species diversity may also determine the level of services that the forest can provide. Swedish national forest data show that while mixed stands often provide more services than monoculture forests, it is the relative abundance of species within the mix that can be the key determinant, and necessary for understanding in forest management.

Capacity for carbon capture and storage in forests may not be monolithic but instead a function of complex dynamics of forest strata and age. The smaller trees that make up the understory in African tropical forests store their carbon longer as compared to sub-canopy and canopy trees and they represent a disproportionately large share of the carbon sink, in spite of their small size.