scholarly journals Tree water relations and climatic variations at the alpine timberline: seasonal changes of sap flux and xylem water potential in Larix decidua Miller, Picea abies (L.) Karst. and Pinus cembra L

1998 ◽  
Vol 55 (1-2) ◽  
pp. 159-172 ◽  
Author(s):  
Tommaso Anfodillo ◽  
Stefano Rento ◽  
Vinicio Carraro ◽  
Luca Furlanetto ◽  
Carlo Urbinati ◽  
...  
Keyword(s):  
Picea Abies ◽  
Water Potential ◽  
Water Relations ◽  
Seasonal Changes ◽  
Larix Decidua ◽  
Sap Flux ◽  
Pinus Cembra ◽  
Xylem Water Potential ◽  
Climatic Variations ◽  
Alpine Timberline

Xylem sap chemistry: seasonal changes in timberline conifers Pinus cembra, Picea abies, and Larix decidua

2018 ◽  
Vol 62 (1) ◽  
pp. 157-165 ◽  
Author(s):  
A. Losso ◽  
A. Nardini ◽  
B. Damon ◽  
S. Mayr
Keyword(s):  
Picea Abies ◽  
Seasonal Changes ◽  
Xylem Sap ◽  
Larix Decidua ◽  
Pinus Cembra

scholarly journals Water relations and hydraulic architecture in Cerrado trees: adjustments to seasonal changes in water availability and evaporative demand

2008 ◽  
Vol 20 (3) ◽  
pp. 233-245 ◽  
Author(s):  
Sandra J. Bucci ◽  
Fabian G. Scholz ◽  
Guillermo Goldstein ◽  
Frederick C. Meinzer ◽  
Augusto C. Franco ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Relations ◽  
Seasonal Changes ◽  
Soil Water Potential ◽  
Woody Species ◽  
Dry Season ◽  
Hydraulic Architecture ◽  
Wet Season ◽  
Evaporative Demand ◽  
Water Deficits

We determined adjustments in physiology and morphology that allow Neotropical savanna trees from central Brazil (Cerrado) to avoid water deficits and to maintain a nearly constant internal water balance despite seasonal changes in precipitation and air saturation deficit (D). Precipitation in the study area is highly seasonal with about five nearly rainless months during which D is two fold higher compared to wet season values. As a consequence of the seasonal fluctuations in rainfall and D, soil water potential changes substantially in the upper 100 cm of soil, but remains nearly constant below 2 m depth. Hydraulic architecture and water relations traits of Cerrado trees adjusted during the dry season to prevent increasing water deficits and insure homeostasis in minimum leaf water potential ψL and in total daily water loss per plant (isohydry). The isohydric behavior of Cerrado trees was the result of a decrease in total leaf surface area per tree, a strong stomatal control of evaporative losses, an increase in leaf-specific hydraulic conductivity and leaf hydraulic conductance and an increase in the amount of water withdrawn from internal stem storage, during the dry season. Water transport efficiency increased in the same proportion in leaves and terminal stems during the dry season. All of these seasonal adjustments were important for maintaining ψL above critical thresholds, which reduces the rate of embolism formation in stems and help to avoid turgor loss in leaf tissues still during the dry season. These adjustments allow the stems of most Cerrado woody species to operate far from the point of catastrophic dysfunction for cavitation, while leaves operate close to it and experience embolism on a daily basis, especially during the dry season.

The control of Phytophthora root rot of avocado with fungicides and the effect of this disease on water relations, yield and ring neck.

1986 ◽  
Vol 26 (2) ◽  
pp. 249 ◽  
Author(s):  
AW Whiley ◽  
KG Pegg ◽  
JB Saranah ◽  
LI Forsberg
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Relations ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Complete Recovery ◽  
Xylem Water Potential ◽  
Physiological Disorder ◽  
Phytophthora Root Rot ◽  
Water Sprays

Avocado trees (cv. Fuerte) were protected from root rot caused by Phytophthora cinnamomi by foliar metalaxyl. Protected trees had higher xylem water sprays with phosethyl-A1 or soil applications of potentials and showed faster and more complete recovery from water stress during the evening than un treated root rot affected trees. protected trees had greater fruit yields and there was a correlation between the incidence of the physiological disorder ring neck and xylem water potential in trees.

Studies on upper timberline: morphology and anatomy of Norway spruce (Picea abies) and stone pine (Pinus cembra) needles from various habitat conditions

1976 ◽  
Vol 54 (14) ◽  
pp. 1622-1632 ◽  
Author(s):  
M. N. Baig ◽  
W. Tranquillini
Keyword(s):  
Picea Abies ◽  
Habitat Conditions ◽  
Pinus Cembra ◽  
Valley Bottom ◽  
Cuticle Formation ◽  
Alpine Timberline ◽  
Upper Timberline ◽  
Wind Exposure ◽  
Cuticle Thickness

The importance of the anatomy of the needles of coniferous trees in determining alpine timberline was studied in the Austrian Alps. Samples of 1- and 2-year-old needles of Picea abies (L.) Karst. and Pinus cembra L. were made from wind-exposed and wind-protected timberline (2140 m above sea level (a.s.l.)), and from the kampfzone (2040 m a.s.l.), forestline (1940 m a.s.l.), and valley bottom (1000 m a.s.l.). The samples were measured for number of needles per centimetre twig, twig length, needle length, cuticle thickness, thickness of epidermis and hypodermis, and depth of stomatal crater. There is a decrease in cuticle thickness with increasing altitude and with increasing wind exposure at timberline, and this is correlated with increased transpiration. The role of inadequate cuticle formation in desiccation damage and mortality of the needles is a significant factor in the control of upper timberline.

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