. Proceedings of the American Society of Agronomy . Stomata and Relative Amount of Water LostFrom the Leaves of Plants. Plant. Atropa belladonna Syringa vulgaris Tilia europcea Hedera helix I Area of TranspiringLeaf-surface in Sq. Cm. 40202020 Relative No. ofStomata Present. j Upper 10I Under 55 / Upper 1001 Under 150 / Upper o1 Under 60 r Upper o\ Under 90 Grams of Water Tran-spired in 24 Hrs. In the latter case, however, there is no water loss from the uppersurface and a very small loss from the lower surface, even thoughit is well supplied with stomata.
. Proceedings of the American Society of Agronomy . Stomata and Relative Amount of Water LostFrom the Leaves of Plants. Plant. Atropa belladonna Syringa vulgaris Tilia europcea Hedera helix I Area of TranspiringLeaf-surface in Sq. Cm. 40202020 Relative No. ofStomata Present. j Upper 10I Under 55 / Upper 1001 Under 150 / Upper o1 Under 60 r Upper o\ Under 90 Grams of Water Tran-spired in 24 Hrs. In the latter case, however, there is no water loss from the uppersurface and a very small loss from the lower surface, even thoughit is well supplied with stomata. The number and size of the stomatais not an indicator of the probable loss of water from a given leafarea when different species or varieties are compared. It is not verycommon that water is lost through an epidermis when no stomata arepresent, but this is true in a few cases. Determining Water Loss from Cuttings. Fig. 38 illustrates also the methods of determining water loss fromcuttings, a is merely a U-tube with a tight rubber cork in each Fig. 38.—Illustration of methods of determining water loss from cuttings. 264 PROCEEDINGS OF THE AMERICAN SOCIETY OF AGRONOMY. It is necessary that the branch or leaf to be tested be so inserted thatit is airtight. The small tube is scaled so that the amount of waterrequired by the leaf or branch can be determined from time to figures a very simple apparatus for determining water loss. Wide-mouthed bottles with ordinary corks can be utilized. A battery ofthis kind of evaporimeter can be quickly set up, and is convenientfor comparing the relative loss between different varieties of plantsunder varying conditions, such as shade and sunshine. Of coursethe records can only be taken for one or two days before the cuttingwilts, but the method is often very useful. Methods of Detennining Water Loss Where Grozmng Plants are Used. Fig. 39 illustrates three methods which have been utilized for thispurpose, a is a small flowerpot with
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