Raman spectroscopy reveals high phloem sugar content in leaves of canopy red oak trees

Hydraulic analysis of water flow through leaves of sugar maple and red oak.

Leaves constitute a substantial fraction of the total resistance to water flow through plants. A key question is how hydraulic resistance within the leaf is distributed among petiole, major veins, minor veins, and the pathways downstream of the veins. We partitioned the leaf hydraulic resistance (R(leaf)) for sugar maple (Acer saccharum) and red oak (Quercus rubra) by measuring the resistance t...

High Performance Method for Skin Roughness Detection Using Raman Spectroscopy

Estimating canopy water content from spectroscopy

Canopy water content is a dynamic quantity that depends on the balance between water losses from transpiration and water uptake from the soil. Absorption of shortwave radiation by water is determined by various frequencies that match overtones of fundamental bending and stretching molecular transitions. Leaf water potential and relative water content are important variables for determining wate...

Nondestructive Estimation of Anthocyanin Content in Autumn Sugar Maple Leaves

A field-portable tool for nondestructive foliar anthocyanin content estimation would be beneficial to researchers in many areas of plant science. An existing commercial chlorophyll content meter was modified to measure an index of anthocyanin content. The ability of the experimental anthocyanin meter (ACM) to estimate total extractable anthocyanin content was tested in sugar maple (Acer sacchar...

Phloem transport in trees.

Phloem is like an enigmatic central banker: we know how important phloem is to plant function, but very little about how phloem functions as part of a whole-plant economy. Phloem transports carbohydrates, produced by photosynthesis and hydrolysis of reserve compounds, to sink tissues for growth, respiration and storage. At photosynthetic tissues, carbohydrates are loaded into phloem (Rennie and...