scholarly journals Responses of sap flow, leaf gas exchange and growth of hybrid aspen to elevated atmospheric humidity under field conditions

AoB Plants ◽  
2014 ◽  
Vol 6 ◽  
Author(s):  
Aigar Niglas ◽  
Priit Kupper ◽  
Arvo Tullus ◽  
Arne Sellin
Keyword(s):  
Gas Exchange ◽  
Sap Flow ◽  
Leaf Gas Exchange ◽  
Field Conditions ◽  
Hybrid Aspen ◽  
Atmospheric Humidity

The effect of strobilurins on leaf gas exchange, water use efficiency and ABA content in grapevine under field conditions

2012 ◽  
Vol 169 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Antonio Diaz-Espejo ◽  
María Victoria Cuevas ◽  
Miquel Ribas-Carbo ◽  
Jaume Flexas ◽  
Sebastian Martorell ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Field Conditions ◽  
Use Efficiency ◽  
Aba Content

scholarly journals ABA, Hydraulics, and Gas Exchange of Split-rooted Apple Trees

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1097C-1097
Author(s):  
Todd C. Einhorn ◽  
Horst W. Caspari ◽  
Steve Green
Keyword(s):  
Gas Exchange ◽  
Time Domain ◽  
Sap Flow ◽  
Leaf Gas Exchange ◽  
Heat Pulse ◽  
Time Domain Reflectometry ◽  
Apple Trees ◽  
Pulse Technique ◽  
Predawn Leaf Water Potential ◽  
Single Leaf

Approach-grafted 1-year-old `Gala'/M7 apple trees were grown with both tops for the remainder of the 2003 season in a greenhouse. Trees were supplied with >100% (control, PRD100) or 50% (PRD50, DI50) of daily ETc either applied to one root compartment only (PRD100, PRD50) or divided evenly across both root compartments (control and DI50). ETc was estimated from gravimetric measurements, and irrigation was switched between wet and dry root compartments several times throughout the experiment. Soil moisture was measured both gravimetrically (tripod) and volumetrically (time-domain reflectometry). Predawn leaf water potential (υpd) and single leaf gas exchange (photosynthesis, stomatal conductance, and transpiration) were recorded daily, and sap flow in stems and roots was monitored continuously using the heat-pulse technique. Leaves were collected for abscisic acid (ABA) determination following gas exchange measurements. Regardless of irrigation placement (i.e., PRD or DI), both 50% ETc treatments experienced similar declines in υpd and single leaf gas exchange relative to control levels. In addition, ABA concentrations were similar for PRD50 and DI50, and were significantly higher than the control and PRD100 treatments. PRD100 trees had similar υpd as control trees; however, gas exchange was reduced >25% compared to the control. Bulk leaf ABA concentration did not differ significantly from control levels and does not by itself explain the down regulation of stomata with PRD100.

Impact of phloem girdling on leaf gas exchange and hydraulic conductance in hybrid aspen

2013 ◽  
Vol 57 (3) ◽  
pp. 531-539 ◽  
Author(s):  
A. Sellin ◽  
A. Niglas ◽  
E. Ounapuu ◽  
A. Karusion
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Hybrid Aspen

IMPROVING THE DEVELOPMENT OF COFFEA ARABICA AFTER CHANGING THE PATTERN OF LEAF GAS EXCHANGE BY WATERING CYCLES

2010 ◽  
Vol 46 (3) ◽  
pp. 381-391 ◽  
Author(s):  
PAULA NOVAES ◽  
JOÃO PAULO SOUZA ◽  
CARLOS HENRIQUE BRITTO ASSIS PRADO
Keyword(s):  
Gas Exchange ◽  
Coffea Arabica ◽  
Leaf Gas Exchange ◽  
Net Photosynthesis ◽  
Area Ratio ◽  
Field Conditions ◽  
Initial Growth ◽  
Initial Development ◽  
Vegetative And Reproductive Growth ◽  
Flowering Intensity

SUMMARYHardening of Coffea arabica saplings by watering cycles (WCs) might be a suitable practice to achieve higher tolerance to low leaf water potential (Ψleaf) before transplanting to the field. As a consequence, hardening could promote growth and biomass gain during the initial development of C. arabica in the field. Thus, the less interrupted initial growth in a changing environment should confer higher flowering intensity in hardened than in control plants. The aim of this work was to verify if leaf gas exchange and Ψleaf behaviour of C. arabica saplings grafted on C. canephora showed consistent alterations during hardening by WCs and if this was effective to improve vegetative and reproductive growth under field conditions. For these reasons, saplings of the Mundo Novo cultivar of C. arabica grafted on C. canephora were submitted to seven WCs over 35 days. Each WC was completed when net photosynthesis was close to zero. The pattern of leaf gas exchange, mainly stomatal conductance (gs), was modified permanently after three WCs and the new pattern of leaf gas exchange could result in a more positive water balance and less interrupted development of C. arabica saplings in the field, particularly due to permanent low values of gs. After field transplantation, hardened plants showed greater height and stem diameter, more leaves and branches, and superior biomass production in leaves, stem and roots than control plants in dry and wet periods. The number of flowers was also significantly higher in hardened than in control plants. On the other hand, similar values were found between control and hardened plants in the leaf area ratio and the shoot/root ratio. Therefore, previous hardening by WCs was effective in improving leaf gas exchange, vegetative and reproductive development under field conditions and maintained the original biomass partitioning among the main plant compartments in dry and wet periods.

Sap flow, leaf gas exchange and chlorophyll fluorescence of container-grown cashew (Anacardium occidentale L.) trees subjected to repeated cycles of soil drying

1998 ◽  
Vol 38 (3) ◽  
pp. 305 ◽  
Author(s):  
S. J. Blaikie ◽  
E. K. Chacko
Keyword(s):  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Sap Flow ◽  
Field Experiments ◽  
Leaf Gas Exchange ◽  
Electron Flow ◽  
Anacardium Occidentale ◽  
Sapwood Area

Summary. Cashew (Anacardium occidentale L.) is an emerging horticultural crop in tropical northern Australia. Supplementary watering is required during the dry season to achieve high yields but irrigation guidelines are not well defined. As an introduction to large-scale field experiments which will aim to define the irrigation requirements for cashew, this experiment was conducted on small, container-grown cashew trees to examine their response to drying soil and to evaluate a range of techniques for measuring tree water use and photosynthesis with possible application in the proposed field experiments. Measurements of sap flow, leaf chlorophyll fluorescence and leaf gas exchange were made on all trees throughout the experimental period. The water use of trees in drying soil was measured using Granier’s sap flow system. Sap flux density (L/dm2 sapwood area . h) of drying trees declined progressively over a 4-day period to a minimum level that was only 10% of the sap flow in the well watered trees. Measurements of leaf gas exchange showed similarly large reductions in photosynthesis and transpiration which were associated with a low (0.05 mol/m2 . s) stomatal conductance in the drying trees. After rewatering, sap flow and leaf gas exchange recovered to the high levels of the well watered trees over 3–4 days. Similar behaviour was observed during the second drying period. Measurements of the ratio of variable to maximum fluorescence, Fv : Fm, an indicator of photoinhibition, were made on dark-adapted leaves before dawn and during the day. Fv : Fm was in the range 0.65–0.80 with no large or sustained differences between drying and well watered trees. When stomatal conductance and net photosynthetic rate progressively declined during the period following irrigation, the quantum yield of photochemical energy conversion in photosystem II, ΦPSII, remained almost constant. It is possible that by providing a pathway for electron flow as an alternative to CO2 assimilation during this period, photorespiration played an important role in avoiding photoinhibition.

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

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