Terrestrial and Floating Aquatic Plants Differ in Acclimation to Light Environment

Abstract

The ability of plants to respond to environmental fluctuations is supported by acclimatory adjustments in plant form and function that may require several days and development of a new leaf. We review adjustments in photosynthetic, photoprotective, and foliar vascular capacity in response to variation in light and temperature in terrestrial plants. The requirement for extensive acclimation to these environmental conditions in terrestrial plants is contrasted with an apparent lesser need for acclimation to different light environments, including rapid light fluctuations, in floating aquatic plants for the duckweed Lemna minor. Relevant features of L. minor include unusually high growth rates and photosynthetic capacities coupled with the ability to produce high levels of photoprotective xanthophylls across a wide range of growth light environments without compromising photosynthetic efficiency. These features also allow L. minor to maximize productivity and avoid problems during an abrupt experimental transfer of low-light-grown plants to high light. The contrasting responses of land plants and floating aquatic plants to the light environment further emphasize the need of land plants to, e.g., experience light fluctuations in their growth environment before they induce acclimatory adjustments that allow them to take full advantage of natural settings with such fluctuations.

Lemnaceae as Novel Crop Candidates for CO2 Sequestration and Additional Applications

“…Overall frond protein content was also lower under elevated CO 2 in the presence of continuous high light (Figure 4j), albeit to a lesser extent than chlorophyll or carotenoid levels. This finding is likely unique to duckweed and is consistent with the role of Ribulose 1,5-bisphosphate Carboxylase/Oxygenase (RuBisCO), the predominant protein in fronds, not only in photosynthesis but also as a vegetative storage protein in duckweed [53] that is maintained at high levels across a wide range of growth light environments [54,55]. This welcome finding thus illustrates the unique ability of duckweed to maintain high protein content under elevated CO 2 .…”

“…In contrast, land plants have lower average levels of antioxidants per leaf dry mass, with relatively low antioxidant levels in the lower versus upper portions of individual leaves [61,62] as well as lower versus upper leaves in a tiered plant canopy [61]. In addition, land plants downsize their pools of various antioxidants and other essential human micronutrients under low growth light intensity more strongly than duckweed [54]. This difference between duckweeds and land plants, along with duckweed's high RGR under low light [54], is advantageous for energy-efficient cultivation of duckweed in controlled environments with relatively low light supply (see also Sections 7 and 8).…”

“…In addition, land plants downsize their pools of various antioxidants and other essential human micronutrients under low growth light intensity more strongly than duckweed [54]. This difference between duckweeds and land plants, along with duckweed's high RGR under low light [54], is advantageous for energy-efficient cultivation of duckweed in controlled environments with relatively low light supply (see also Sections 7 and 8).…”

Optimising plant form and function for controlled environment agriculture in space and on earth

“…Duckweeds contain between 20% and 35% protein representing all essential amino acids, 4%-7% fats of which the majority are polyunsaturated fatty acids, and 4%-10% starch. 44 Duckweed can maintain high photosynthetic capacity over a range of light conditions 45,46 making it highly suitable for CEA. Experiments to test duckweed growth in custom mG-Lilypond hydroponic chambers were included in the Blue Origin New Shepard Launch.…”

Photosynthesis under Environmental Fluctuations: A Challenge for Plants, a Challenge for Researchers

“…Particularly intriguing is the case of the minute floating water plant Lemna minor , which is dealt with in the comprehensive review written by López-Pozo, Adams, Polutchko, and Demmig-Adams. The authors highlight a number of this duckweed’s unusual properties which allow it to thrive in a fluctuating environment [ 13 ]. Although this information may not be generalizable to other species, the environmental pressure of the aquatic environment, particularly the floating habitat, has certainly had a major role in the evolution of duckweed’s photosynthetic traits.…”