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DAVID M. GATES
VII. METHODS FOR ANSWERING ECOLOGICAL QUESTIONS
We tail now turn to the specific questions asked earlier.
A. PLANT AND ENVIRONMENT
How dues the environment influence an individual plant of a given
species e+t any stage of its life history? How are plant and environment
coupled together? It was shown in terms of energy flow how the plant
and the environment are coupled together. These methods now are
well-established and the input data necessary are: environmentalradiatiou intensity, air temperature, relative humidity and wind;
coupling factors - leaf absorptivity to radiation, leaf area, leaf size,
shape and orientation, and diffusion resistance to transpiration; and
the concequences show up with the value of leaf temperature, trimspiration rate, and net photosynthetic and respiretion rates deoting
productivity.
B. QENOTYPIC AND PHENOTYPIC PLANT PBOPERTIES
What are the ecologically significant genotypic and phenotypic properties of plants? There are many. Leaf size and shape is a genotypical
property which affects the coupling between leaf temperature and the
air temperature through ita influence in the convection coe5cient and
more sebtly in its influence on the transpiration rate through the
boundary layer resistance and the leaf temperature. Through the energy
budget equation for a leaf and computation it is shown that leaf temperature is only little affected by leaf size. A similar computation concerning the influence of leaf size on transpiration rate per unit leaf area
shows there are conditions when the dimension produces a substantial
influence. Shade leaves are substantially larger than are sunlit leaves.
The absorptivity of the leaf to incident radiation depends upon the
leaf thickness, the internal structure and pigment content, and upon
the surface characteristics, each of which are genotypically influenced.
These factors make 8 substantial difference in the amount of energy
absorbed and the differences are important ecologically. Only a few
superfichA comparisons have been made and very little is known concerning ',he ecological consequences. The leaf reflectivity and transmimivity is strongly affected by the surface properties such as pubescence, end by leaf thickness and internal composition. The abeorptivity -- 1 -0 - reflectivity - transmissivity.
The internal diffusion resistance to the loss of water vapor through
the stomates depends upon the size, shape, and number density of stomates which in turn are genotypically controlled as well as phenotypically influenced. Through the diffusion resistance strong control of
DAVID M. GATES
VII. METHODS FOR ANSWERING ECOLOGICAL QUESTIONS
We tail now turn to the specific questions asked earlier.
A. PLANT AND ENVIRONMENT
How dues the environment influence an individual plant of a given
species e+t any stage of its life history? How are plant and environment
coupled together? It was shown in terms of energy flow how the plant
and the environment are coupled together. These methods now are
well-established and the input data necessary are: environmentalradiatiou intensity, air temperature, relative humidity and wind;
coupling factors - leaf absorptivity to radiation, leaf area, leaf size,
shape and orientation, and diffusion resistance to transpiration; and
the concequences show up with the value of leaf temperature, trimspiration rate, and net photosynthetic and respiretion rates deoting
productivity.
B. QENOTYPIC AND PHENOTYPIC PLANT PBOPERTIES
What are the ecologically significant genotypic and phenotypic properties of plants? There are many. Leaf size and shape is a genotypical
property which affects the coupling between leaf temperature and the
air temperature through ita influence in the convection coe5cient and
more sebtly in its influence on the transpiration rate through the
boundary layer resistance and the leaf temperature. Through the energy
budget equation for a leaf and computation it is shown that leaf temperature is only little affected by leaf size. A similar computation concerning the influence of leaf size on transpiration rate per unit leaf area
shows there are conditions when the dimension produces a substantial
influence. Shade leaves are substantially larger than are sunlit leaves.
The absorptivity of the leaf to incident radiation depends upon the
leaf thickness, the internal structure and pigment content, and upon
the surface characteristics, each of which are genotypically influenced.
These factors make 8 substantial difference in the amount of energy
absorbed and the differences are important ecologically. Only a few
superfichA comparisons have been made and very little is known concerning ',he ecological consequences. The leaf reflectivity and transmimivity is strongly affected by the surface properties such as pubescence, end by leaf thickness and internal composition. The abeorptivity -- 1 -0 - reflectivity - transmissivity.
The internal diffusion resistance to the loss of water vapor through
the stomates depends upon the size, shape, and number density of stomates which in turn are genotypically controlled as well as phenotypically influenced. Through the diffusion resistance strong control of