scholarly journals Transpiration, Water Absorption, and Internal Water Balance of Cotton Plants as Affected by Light and Changes in Saturation Deficit

1966 ◽  
Vol 41 (1) ◽  
pp. 71-74 ◽  
Author(s):  
W. L. Ehrler ◽  
C. H. M. van Bavel ◽  
F. S. Nakayama
Keyword(s):  
Water Balance ◽  
Water Absorption ◽  
Saturation Deficit ◽  
Internal Water ◽  
Cotton Plants

Ecological studies of larval ticks in South Africa (Acarina: Ixodidae)

Parasitology ◽  
1972 ◽  
Vol 65 (3) ◽  
pp. 469-490 ◽  
Author(s):  
J. G. H. Londt ◽  
G. B. Whitehead
Keyword(s):  
South Africa ◽  
Relative Humidity ◽  
Water Balance ◽  
Field Data ◽  
Amblyomma Hebraeum ◽  
Ecological Studies ◽  
Saturation Deficit ◽  
Vegetation Height ◽  
Boophilus Decoloratus ◽  
Glass Rods

The distribution of larval ticks in relation to vegetation cover was studied on two coastal farms in the Port Alfred district of the Cape Province. The following five species were found: Boophilus decoloratus (Koch), Amblyomma hebraeum Koch, Ixodes pilosus Koch, Haemaphysalis silacea Robinson and Rhipicephalus evertsi Neumann. B. decoloratus predominated in short protected vegetation, I. pilosus and H. silacea in short covered vegetation and A. hebraeum in medium-to-tall protected vegetation. R. evertsi was collected in too small numbers to allow any correlation to be established. Both I. pilosus and H. silacea demonstrated activity peaks during the winter months. Microclimatic measurements indicated that larval ticks were not usually collected in microhabitats which experienced midday saturation deficits in excess of approximately 10 mm Hg. Behavioural studies on larval ticks climbing glass rods demonstrated the possible association of larvae with a definite vegetation height. The optimal vegetation heights were correlated with field data. The water balance of some tick species was studied and it was found that at 26 °C a relative humidity of 70% or more (i.e. above 7·53 mm Hg saturation deficit) was required by these larvae. Larvae lost water to the atmosphere at humidities lower than this value and took up water vapour from the atmosphere at values higher than 70% R.H. They were shown to be able to imbibe water through the mouthparts, and this possibly has survival value.

Absorption de l'eau atmosphérique par la partie aérienne d'un chaméphyte de la Tunisie présaharienne : l’Anthyllis henoniana (Fabaceae)

1994 ◽  
Vol 72 (8) ◽  
pp. 1222-1227 ◽  
Author(s):  
Jean-Marc Ourcival ◽  
André Berger ◽  
Édouard Le Floc'h
Keyword(s):  
Water Balance ◽  
Water Absorption ◽  
Water Potential ◽  
Key Words ◽  
Cross Sections ◽  
Vascular System ◽  
Atmospheric Water ◽  
Atmospheric Humidity ◽  
The Many ◽  
Made In

Measurements of predawn water potential made in the presaharian Tunisia (Médenine) on A. henoniana suggest that this species is able to absorb directly atmospheric water through its leaves and (or) stems. Measurements of water potential were also made on several plants in controlled conditions. Cross sections of stems of various ages and of leaves were examined. There was a good correlation between the thickness of the cortical parenchymatous tissue in leaves and young stems and the ability of a plant to maintain a less negative water potential in conditions of high atmospheric humidity. The water is apparently taken up by the vascular system. This ability would allow A. henoniana to benefit from the many dew days observed in its area of distribution and would improve its water balance. Key words: Anthyllis henoniana, dew, water potential, water absorption, water balance.

scholarly journals Internal Water Balance of Barley Under Soil Moisture Stress

1968 ◽  
Vol 43 (6) ◽  
pp. 968-972 ◽  
Author(s):  
Agustin A. Millar ◽  
Murray E. Duysen ◽  
Guy E. Wilkinson
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Moisture Stress ◽  
Soil Moisture Stress ◽  
Internal Water

Water Balance in Manduca Sexta Caterpillars: Water Recycling From the Rectum

1989 ◽  
Vol 141 (1) ◽  
pp. 33-45 ◽  
Author(s):  
STUART E. REYNOLDS ◽  
KAREN BELLWARD
Keyword(s):  
Epithelial Cells ◽  
Water Balance ◽  
Water Absorption ◽  
Water Content ◽  
Manduca Sexta ◽  
Rectal Wall ◽  
Tobacco Hornworm ◽  
Water Recycling ◽  
Water Reabsorption ◽  
Ultrastructural Appearance

Tobacco hornworm (Manduca sexta) caterpillars are able to regulate the water content of their body when fed on diets of markedly different water content. This regulation extends to the water content of food within the gut. Regulation of body water is achieved by adjusting the amounts of water lost with the faeces. The rectum is shown to be the principal site of water reabsorption from the faeces. The rate of rectal water absorption is shown to vary with the water content of the food and thus according to need. Water reabsorbed from the rectal contents is recycled and added to the contents of the midgut. The ultrastructural appearance of epithelial cells in the rectal wall is that expected of a fluid-transporting tissue. The ileum appears to play little or no part in water recycling.

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