Annals of the Royal Botanic Garden, Calcutta Volume 6

Annals of the Royal Botanic Garden, Calcutta Volume 6

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...that it has been one of continuous sunshine, and that no special interfering factors have come into play, the conditions both of the tissues themselves and of their environment are very different from what they were in the early morning. The tissues have for so long been exposed to active transpiratory loss as to ensure a great diminution, if not a total expenditure, of any surplus of water-content beyond the amount necessary to meet the immediate demands of the active elements, and atmospheric conditions are such as to imply much more active transpiratory loss than that which was present in the morning. Under the circumstances, it is only natural that any phenomena of movement dependent on alterations in the relations of supply and loss of water should show certain modifications in character, and that these modifications should be of the nature of those which are actually present. The supply of reserve-water within the water-conducting system being greatly decreased or practically exhausted, and transpiratory loss being greatly increased, the maintenance of the diurnal position is secured only by means of immediate expenditure of the water furnished by the stream traversing the water-conducting system from the roots; and hence separation from the axis implies an immediate and very considerable drain upon the active tissues. This secures proportionately rapid and complete action in the pinnules and considerable movement in the secondary rachises. Under such circumstances the recovery of the diurnal position is naturally less complete, exposure to direct sunshine is followed by more rapid movements and more frequently by abrupt, spreading movements, and the secondary assumption of the nocturnal ppsition is not only much more complete than...show more

Product details

  • Paperback | 140 pages
  • 189 x 246 x 8mm | 263g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236852397
  • 9781236852397