. Proceedings of the American Society of Agronomy . rrying on suchwork in the field. It is a well-known fact that each stoma of a leaf is connected withan intercellular air-space so that there is a free movement of the at-mospheric air in and out of the leaf. This is a continuous process inthe living plant and removes the surplus moisture exuded into theair passages. ^ Rothamsted Memoirs, Field Experiments, Vol. i, 1847-1863. 262 PROCEEDINGS OF THE AMERICAN SOCIETY OF AGRONOMY. Demonstrating Water Loss from Cut Leaves. Fig 37 illustrates two methods used in demonstrating the loss ofwater from
. Proceedings of the American Society of Agronomy . rrying on suchwork in the field. It is a well-known fact that each stoma of a leaf is connected withan intercellular air-space so that there is a free movement of the at-mospheric air in and out of the leaf. This is a continuous process inthe living plant and removes the surplus moisture exuded into theair passages. ^ Rothamsted Memoirs, Field Experiments, Vol. i, 1847-1863. 262 PROCEEDINGS OF THE AMERICAN SOCIETY OF AGRONOMY. Demonstrating Water Loss from Cut Leaves. Fig 37 illustrates two methods used in demonstrating the loss ofwater from leaves, a is a simple apparatus, made by clamping theleaf between two pieces of glass with a small piece of cobalt the paper has been clamped on the leaf a few minutes, theglass plates are removed, and the fact that water has come throughthe leaf is demonstrated by the paper changing color. By this meansit can be determined that water loss may take place from one or bothsides of the leaf, b illustrates a method of determining the exact. amount of water exuded from two sides of a leaf. Two inverted belljars are affixed to the leaf, with vaseline around the edges. In thetwo watch glasses a water absorbent is placed, as calcium the leaf has been allowed to transpire a given length of time,the amount of water loss is determined by reweighing the watch I gives some data secured by this last apparatus. It is shownin this that the number of stomata is not always an indicator of therelative amount of water loss for a comparison of the loss from aleaf of Tilia europcca and from one of Hedcra helix shows, in theformer case, considerable loss from the upper surface, even thoughthere are no stomata present, and a fairly large loss from the lowersurface. MONTGOMERY: WATER REQUIREMENTS OF CROPS. 263 Table I.—Niimhcr of Stomata and Relative Amount of Water LostFrom the Leaves of Plants. Plant. Atropa belladonna Syringa vulgaris Tilia europcea Hedera he
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