Abstract Detail

Physiology

Miller, Elise [1], Savage, Jessica [2].

How phloem anatomy is influenced by carbon sources, sinks and plant growth.

Plants respond to the environment through plastic changes in their growth patterns, specifically carbon allocation, which often allows plants to acclimate to environmental changes. However, little research has been done on the plasticity of carbon transport capacity in the phloem, and it is unknown what influences variation among plants in their transport phloem anatomy. One challenge with studying transport phloem is that it is difficult to identify sieve elements (conducting cells in the phloem) in cross-section using light or fluorescent microscopy. As a result, there is limited data on the phloem conductive area, specifically in entire stem/branch cross-sections. In this study, we immunolabeled sieve element walls with the monoclonal LM26 antibody. This technique is novel because it is less time consuming than previously employed techniques like electron microscopy and appears to only tag functional sieve elements. To study the plasticity of phloem anatomy and phloem hydraulic conductivity, Populus tremuloides seedlings were grown under two different light treatments, 800 μmol m^-2 s^-1 and 100 μmol m^-2 s^-1, for ten weeks. The seedlings grown under high light were shorter, had smaller stem length to diameter ratios, fewer leaves, and longer roots compared to the low light seedlings. The high light plants had a higher sieve element density while the low light plants had a larger average sieve element lumen area. Interestingly, the total sieve element area in each seedling section was not different, but the theoretical phloem hydraulic conductivity was higher in the low light seedlings. These results suggest that stem length and sieve element packing might have a strong impact on transport phloem anatomy and phloem hydraulic conductivity in seedlings. By studying how changes in growth in sources and sinks correspond to changes in the transport phloem, we can better understand how the environment affects carbon transport in plants.

1 - University of Minnesota Duluth, Department of Biological Sciences, 1035 Kirby Drive 207 Swenson Science Building, Duluth, MN, 55812, USA
2 - University Of Minnesota - Duluth, Biology, 1035 Kirby Drive, 207 Swenson Science Buildling, Duluth, MN, 55812, United States

Keywords:
Phloem Hydraulic Conductivity
growth
development
Phloem Architecture.

Presentation Type: Oral Paper
Session: PHYS, Physiology
Location: /
Date: Wednesday, July 21st, 2021
Time: 2:00 PM(EDT)
Number: PHYS013
Abstract ID:973
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize,Physiological Section Best Paper Presentation