The fossil record suggests stomata-like pores were present on the surfaces of land plants over 400 million years ago. Whether stomata arose once or whether they arose independently across newly evolving land plant lineages has long been a matter of debate. In Arabidopsis, a genetic toolbox has been identified…

This Update focuses on the starch that accumulates in the guard cells that control stomatal pore size and thus the exchange of water vapor, CO2 and O2 between the leaf and the atmosphere. Transitory starch in these cells plays a key role in determining the velocity of stomatal opening in the light. This…

Focus Collections are an online collection of papers intended to supplement Plant Physiology® Focus Issues. Papers published in Plant Physiology® two years prior to and those published for up to two years after the Focus Issue will be included. Reactive Oxygen Species The Reactive Oxygen…

Most-read rankings are recalculated at the beginning of the month and are based on full-text and pdf views. See the current list of 100 most-read articles for the past year here.

Plants have evolved a variety of mechanisms to synchronize flowering with their environment to optimize reproductive success. Many species flower in spring when the photoperiod increases and the ambient temperatures become warmer. Winter annuals and biennials have evolved repression mechanisms that prevent…

Plants sense changes in day length (= photoperiod) as a reliable seasonal cue to regulate important developmental transitions such as flowering. Integration of various external light information into the circadian clock-controlled mechanisms enables plants to precisely measure photoperiod changes in…

Biogeographic studies suggest that the degree of fatty acid unsaturation in oilseeds has played a major role in adapting plants to temperature. The enzymes that are primarily responsible for producing polyunsaturated fatty acids in seed oils are the microsomal ω-6 and ω-3 fatty acid desaturases FAD2…

Current available evidence suggests that the location of the sites of evaporation is important for many questions across plant physiology, including patterns of leaf isotopic enrichment, maintenance of mesophyll water status, stomatal regulation, and interpretation of measured stomatal and leaf hydraulic…