This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...What in this connection is true of leaves we must argue to be probably true of bolls, although we have as yet only indirect evidence of it; Duncan and others found that the removal of bolls appeared to reduce shedding to some extent, yet their experiments were not deemed conclusive. Precisely how much water deficit or ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...What in this connection is true of leaves we must argue to be probably true of bolls, although we have as yet only indirect evidence of it; Duncan and others found that the removal of bolls appeared to reduce shedding to some extent, yet their experiments were not deemed conclusive. Precisely how much water deficit or whether indeed the water deficit of a particular day within observed limits suffices to cause shedding we do not know. In this connection the following experiment has interest: Experiment 11.--Begun August 19th, 17 hr. A section of tissue was excised from the internode below the insertion of the pedicel of several (20) bolls and large squares. In 15 cases the tissue was removed from below the square or boll and was so done as to remove all tissue proper to the member. In five cases the tissue was removed below the corresponding leaf, cutting away a piece of the median leaf-trace and some adjacent tissue. The following resulted: Fig. 7. Shedding frequencies after root pruning, and excision of tissues, s = squares; b = bolls. DAY. NOTES. 21st, 1 boll, 11.2 mm. diam. shed. The injury was on the leaf side. 22nd, 1 boll, 11.5 mm. diam. shed. Injury on the boll side. 23rd, 2 bolls shed, 12 and 15 mm. diam. Injury on boll side. 28th, 2 bolls shed, injury on boll side. Although abscission occurred in six out of the 20 cases those which gave negative results are of chief significance. The result that the excision of vascular tissue would not serve to hinder water movement sufficiently to cause shedding was somewhat unexpected, but it had been found true in other plants (Lloyd, 1914a) to be inefficient. The result seems to be something of a shock to the idea of delicate balance, nevertheless it is possible that, granted a generally sufficient amount of ...
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