Impacts of precommercial thinning on gas exchange, midday water potential, and chlorophyll content in Pinus nigra subsp. pallasiana stand from the semiarid region

Trees ◽  
2020 ◽  
Vol 34 (5) ◽  
pp. 1169-1181
Author(s):  
Esra Bayar ◽  
Ayşe Deligöz
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Chlorophyll Content ◽  
Pinus Nigra ◽  
Semiarid Region ◽  
Precommercial Thinning

The Effect of Water Shortage on Potted Peach Trees in Relation to Ecophysiological Parameters and Infra-red Thermometry

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541b-541
Author(s):  
Rita Giuliani ◽  
James A. Flore
Keyword(s):  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Early Detection ◽  
Water Potential ◽  
Canopy Temperature ◽  
Water Shortage ◽  
Development Rate ◽  
Plant Water ◽  
Infra Red ◽  
Peach Trees

Potted peach trees grown outdoors during the 1997 season were subjected to drought and subsequent rewatering to evaluate their dynamic response to soil water content. The investigation was primarily focused on the early detection of plant water stress to prevent negative effects on the growth. Leaf chlorophyll fluorescence and canopy temperature estimates (by infra-red thermometry) were conducted. Drought effect on physiological processes were detected through by estimates of canopy development rate, leaf gas-exchange measurements; while leaf water potential was measured to characterize plant water status. A decrease in the canopy's development rate was found 1 week after irrigation was stopped, which also coincided with a more-negative leaf water potential, whereas a decrease of the gas-exchange activities occurred several days later. No significant differences between the stressed and control plants were recorded by the chlorophyll fluorescence parameters (Fo, Fm, Fv and the ratio Fv/Fm), whereas the infra-red estimates of canopy temperature detected a slight increase of the canopy surface temperature (connected to the change of leaf energy balance and in relation to partial stomatal closure) on the non-irrigated plants 1 week after the beginning of the trial. The use of infra-red thermometry for early detection of water shortage is discussed.

scholarly journals The Effect of Grapevine Age (Vitis vinifera L. cv. Zinfandel) on Phenology and Gas Exchange Parameters over Consecutive Growing Seasons

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 311
Author(s):  
Vegas Riffle ◽  
Nathaniel Palmer ◽  
L. Federico Casassa ◽  
Jean Catherine Dodson Peterson
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Management Practices ◽  
Leaf Water ◽  
Sugar Accumulation ◽  
Gas Exchange Parameters ◽  
Growing Season Length ◽  
Growing Seasons ◽  
Exchange Parameters

Unlike most crop industries, there is a strongly held belief within the wine industry that increased vine age correlates with quality. Considering this perception could be explained by vine physiological differences, the purpose of this study was to evaluate the effect of vine age on phenology and gas exchange parameters. An interplanted, dry farmed, Zinfandel vineyard block under consistent management practices in the Central Coast of California was evaluated over two consecutive growing seasons. Treatments included Young vines (5 to 12 years old), Control (representative proportion of young to old vines in the block), and Old vines (40 to 60 years old). Phenology, leaf water potential, and gas exchange parameters were tracked. Results indicated a difference in phenological progression after berry set between Young and Old vines. Young vines progressed more slowly during berry formation and more rapidly during berry ripening, resulting in Young vines being harvested before Old vines due to variation in the timing of sugar accumulation. No differences in leaf water potential were found. Young vines had higher mid-day stomatal conductance and tended to have higher mid-day photosynthetic rates. The results of this study suggest vine age is a factor in phenological timing and growing season length.

Photosynthesis and Transpiration in Damaged and Undamaged Spruce Trees

1996 ◽  
Vol 51 (3-4) ◽  
pp. 200-210 ◽  
Author(s):  
Aloysius Wild ◽  
Peter Sabel ◽  
Lucia Wild-Peters ◽  
Ursula Schmieden
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Natural Habitat ◽  
Late Summer ◽  
Net Photosynthesis ◽  
Diurnal Course ◽  
Physiological Homeostasis ◽  
Use Efficiency ◽  
Needle Loss ◽  
Light Saturation Curves

Abstract The investigations presented here focus on the CO2/H2O gas exchange in damaged and undamaged spruce trees while using open-air measurements as well as measurements under defined conditions in the laboratory. The studies were performed at two different sites in the Hunsrück and the Westerwald mountains. In the laboratory the CO2/H2O gas exchange was measured on detached branches under controlled conditions in the course of two years. CO2 saturation curves were also generated. In addition CO2 compensation points were deter­ mined employing a closed system. In the natural habitat diurnal course measurements of photosynthesis and transpiration as well as light-saturation curves for photosynthesis were performed. In parallel with the photosynthesis and transpiration measurements, measurements of the water potential were taken at both locations. The photosynthetic capacity and transpiration rate show a typical annual course with pronounced maxima in spring and late summer and minima in summer and winter. The needles of the damaged trees exhibit higher transpiration rates and a distinct reduction in photosyn­ thesis than the needles of the undamaged trees during two seasons. The diurnal course measurements of net photosynthesis and transpiration show a maximum in photosynthesis and transpiration in the afternoon in May and September, but a characteristic midday depression in July. Photosynthesis was markedly lower and transpiration higher in the needles of the damaged trees. The damaged trees show a lower increase in the light and CO2 saturation curves and higher CO2 compensation points as compared to the undamaged trees. The water potential reaches much lower values during the course of the day in needles of the dam­ aged trees. The reduction of the photosynthetic rate on one hand and the increase in transpiration on the other hand result in an extreme lowering of the water use efficiency in photosynthesis. The damage to the thylakoid membranes and to the guard cells obviously results in a pro­ found disturbance of the physiological homeostasis of the needles and could thus lead to premature needle loss.

scholarly journals Influence of Irrigation Regime on Water Relations, Gas Exchange, and Growth of Two Field-grown Redbud Varieties in a Semiarid Climate

2014 ◽  
Vol 32 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Lindsey Fox ◽  
Amber Bates ◽  
Thayne Montague
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Leaf Area ◽  
Shoot Elongation ◽  
Sectional Area ◽  
Irrigation Regime ◽  
Cross Sectional ◽  
Area Increase ◽  
Irrigation Volume

For three growing seasons (2003–2005) two newly planted, field-grown redbud (Cercis canadensis L.) varieties were subjected to three reference evapotranspiration (ETo)-based irrigation regimes (100, 66, and 33% ETo). Over this time period, water relations (pre-dawn leaf water potential), gas exchange (mid-day stomatal conductance), and growth data (trunk cross sectional area increase, tree leaf area, and shoot elongation) were measured. Pre-dawn leaf water potential (ψl) was more negative for trees receiving the least amount of irrigation, and for Mexican redbud [C. canadensis var. mexicana (Rose) M. Hopkins] trees. However, mid-day stomatal conductance (gs) was similar for Texas redbud (C. canadensis var. texensis S. Watson) trees across the three irrigation regimes, and was highest for Mexican redbud trees receiving the greatest amount of irrigation volume. Growth varied by variety and irrigation regime. Trunk cross sectional area increase was greatest for Mexican redbud trees, leaf area was highest for trees receiving the greatest amount of irrigation, and shoot elongation was greatest for trees receiving the 66% ETo irrigation regime. However, despite differing irrigation volumes, greatest gas exchange and growth was not necessarily associated with greatest irrigation volume. When considering conservation of precious water resources, these redbud varieties maintain adequate growth and appearance under reduced irrigation.

scholarly journals Photosynthetic Performance of Guaranazeiro Plants as Affected by Glyphosate Application

2020 ◽  
Vol 12 (10) ◽  
pp. 287
Author(s):  
Bruna N. Leite ◽  
Karla Gabrielle D. Pinto ◽  
Victor Alexandre H. F. dos Santos ◽  
Marciel J. Ferreira ◽  
Sônia Maria F. Albertino
Keyword(s):  
Gas Exchange ◽  
Chlorophyll Content ◽  
Photosynthetic Performance ◽  
Productive Performance ◽  
Weed Species ◽  
Short Term ◽  
Paullinia Cupana ◽  
Process Gas ◽  
Quantum Efficiency Of Psii ◽  
Relative Chlorophyll Content

The unsuitable use of herbicides damages many cultures. In cases of high infestations and presence of aggressive weed species in guarana (Paullinia cupana) culture, glyphosate application is advisable, but its impact on guarana physiology is unknown. Therefore, leaf photosynthetic characteristics were measured with the aim of identifying if the photosynthetic performance of guaranazeiro plants is affected in response to glyphosate application. Three glyphosate doses (0 (control); 324 and 432 g a.i. ha-1) were applied to two guaranazeiro cultivars (BRS-Andirá and BRS-Maués) selected on the basis of productive performance. An analysis was made of the effects of these doses on characteristics that represent the photosynthetic process: gas exchange, maximum quantum efficiency of PSII, performance index and chlorophyll content. The application of glyphosate did not affect the short-term responses relative chlorophyll content (SPAD index) and light use (chlorophyll a fluorescence). After 168 h, there were changes only in gas exchange variables. The effects of glyphosate doses on gas exchange was different between guaranazeiro cultivars. The photosynthetic performance of the guaranazeiro seems to be tolerant to the effects of short-term of glyphosate application.

scholarly journals Physiological Performance of Pyrus pyraster L. (Burgsd.) and Sorbus torminalis (L.) Crantz Seedlings under Drought Treatment

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1496
Author(s):  
Viera Paganová ◽  
Marek Hus ◽  
Zuzana Jureková
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Water Scarcity ◽  
Prolonged Exposure ◽  
Leaf Gas Exchange ◽  
Total Biomass ◽  
Drought Treatment ◽  
Water Regimes ◽  
Sorbus Torminalis ◽  
Pyrus Pyraster

In this study, seedlings of Pyrus pyraster and Sorbus torminalis were grown for 60 days in the regulated environment of a growth chamber under different water regimes. The measured indicators were the growth and distribution of mass to organs, total biomass, root to shoot mass ratio (R:S), and gas exchange parameters (gs, E, An, and water use efficiency (WUE)). The amount of total biomass was negatively affected by drought. Differences between species were confirmed only for the dry matter of the leaves. P. pyraster maintained the ratio of the mass distribution between belowground and aboveground organs in both variants of the water regime. S. torminalis created more root length for a given dry-mass under drought treatment, but its R:S was lower compared to P. pyraster. The water potential of the leaves (Ψwl) was affected by substrate saturation and interspecific differences. P. pyraster had a demonstrably higher water potential and maintained this difference even after prolonged exposure to drought. After 30 days of different water regimes, Pyrus maintained higher values of gs, An, and E in control and drought treatments, but over a longer period of drought (after 50 days), the differences between species were equalized. The changes of the leaf gas exchange for Pyrus were accompanied by a significant increase in WUE, which was most pronounced on the 40th day of the experiment. A significant and strong relationship between WUE and gs was demonstrated. The results confirmed the different physiological performances of seedlings of tree species and the different mechanisms of their response to water scarcity during drought treatment. P. pyraster presented more acclimation traits, which allowed this taxon to exhibit better performance over a longer period of water scarcity.

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