Stem and leaf water potentials, gas exchange, sap flow, and trunk diameter fluctuations for detecting water stress in lemon trees

Trees ◽  
2005 ◽  
Vol 20 (1) ◽  
pp. 1-8 ◽  
Author(s):  
M. Fernanda Ortuño ◽  
Yelitza García-Orellana ◽  
Wenceslao Conejero ◽  
M. Carmen Ruiz-Sánchez ◽  
Juan José Alarcón ◽  
...  
2005 ◽  
Vol 54 (2) ◽  
pp. 155-162 ◽  
Author(s):  
M.F. Ortuño ◽  
J.J. Alarcón ◽  
E. Nicolás ◽  
A. Torrecillas

1992 ◽  
Vol 43 (3) ◽  
pp. 659 ◽  
Author(s):  
L Guobin ◽  
DR Kemp ◽  
GB Liu

The effect of water stress during summer and recovery after rain on herbage accumulation, leaf growth components, stomatal conductance and leaf water relations of white clover (Trifolium repens cv. Haifa) and phalaris (Phalaris aquatica cv. Australian Commercial) was studied in an established mixed pasture under dryland (dry) or irrigated (wet) conditions. Soil water deficits under dry conditions reached 150 mm and soil water potentials in the top 20 cm declined to nearly -2 MPa after 50 days of dry weather. Water stress severely restricted growth of both species but then after rain fell, white clover growth rates exceeded those of phalaris. Under irrigation, white clover produced twice the herbage mass of phalaris but under dry conditions herbage production was similar from both species. Leaf appearance rates per tiller or stolon were slightly higher for white clover than phalaris but were reduced by 20% under water stress in both species. Leaf or petiole extension rates were more sensitive to water stress than leaf appearance rates and declined by 75% in phalaris and 90% in white clover. The ratio of leaf or petiole extension rates on dry/wet treatments was similar for both species in relation to leaf relative water contents, but in relation to leaf water potentials phalaris maintained higher leaf growth rates. Phalaris maintained a higher leaf relative water content in relation to leaf water potentials than did white clover and also maintained higher leaf water potentials in relation to the soil water potential in the top 20 cm. Stomata1 conductances for both species declined by 80-90% with increasing water stress, and both species showed similar stomatal responses to bulk leaf water potentials and leaf relative water contents. It is suggested that the poorer performance of white clover under water stress may be due principally to a shallower root system than phalaris and not due to any underlying major physiological differences. The white clover cultivar used in this study came from the mediterranean region and showed some different responses to water stress than previously published evidence on white clover. This suggests genetic variation in responses to water stress may exist within white clover. To maintain white clover in a pasture under dry conditions it is suggested that grazing practices aim to retain a high proportion of growing points.


Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 315
Author(s):  
Aureliano C. Malheiro ◽  
Mafalda Pires ◽  
Nuno Conceição ◽  
Ana M. Claro ◽  
Lia-Tânia Dinis ◽  
...  

The present research aimed to evaluate the water dynamics of grapevines trained in Cordon and Guyot systems by coupling sap flow and trunk diameter measurements under Mediterranean climate conditions. The study was conducted in a vineyard with Touriga-Nacional located at the Douro Valley, Portugal, during 2017. The results showed daily trunk diameter fluctuations (TDFs), with the contraction, recovery and increment phases and higher sap flow (SF) rates at earlier stages. Under harsh pedoclimatic conditions, SF was reduced and TDF flattened. Rehydration and stomatal mechanisms were mostly associated with these responses. Guyot vines showed higher changes in TDF for the same SF values, whereas the TDFs of Cordon vines remained practically unchanged over maturation. Guyot vines generally showed increased values of cumulative increment and maximum daily trunk shrinkage. Although Guyot vines had a similar leaf area index (LAI), they showed higher SF/LAI ratios than Cordon vines. These results highlight the effect of the shorter length of the hydraulic pathways of the Guyot training system, in contrast to the higher trunk and the permanent horizontal branch (cordon) of the Cordon training system, indicating good adaptation to local pedoclimatic conditions. The study pointed to the complementary use of both techniques in the evaluation of grapevine water dynamics.


1989 ◽  
Vol 16 (6) ◽  
pp. 549 ◽  
Author(s):  
SL Steinberg ◽  
MJ Mcfarland ◽  
JC Miller

A gradation, that reflects the maturity of the leaves, exists in the leaf water, osmotic and turgor potential and stomatal conductance of leaves along current and 1-year-old branches of peach. Predawn leaf water potentials of immature folded leaves were approximately 0.24 MPa lower than mature leaves under both well-watered and dry conditions. During the daytime the leaf water potential of immature leaves reflected the water potential produced by water flux for transpiration. In well- watered trees, mature and immature unfolded leaves had a solute potential at least 0.5 MPa lower than immature folded leaves, resulting in a turgor potential that was approximately 0.8 MPa higher. The turgor requirement for growth appeared to be much less than that maintained in mature leaves. As water stress developed and leaf water potentials decreased, the osmotic potential of immature folded leaves declined to the level found in mature leaves, thus maintaining turgor. In contrast, mature leaves showed little evidence of turgor maintenance. Stomatal conductance was lower in immature leaves than in fully mature leaves. With the onset of water stress, conductance of mature leaves declined to a level near that of immature leaves. Loss of turgor in mature leaves may be a major factor in early stomatal closure. It was concluded that osmotic adjustment played a role in maintenance of a leaf water status favorable for some growth in water-stressed immature peach leaves.


1995 ◽  
Vol 13 (4) ◽  
pp. 178-181 ◽  
Author(s):  
Daniel M. Lauderdale ◽  
Charles H. Gilliam ◽  
Donald J. Eakes ◽  
Gary J Keever ◽  
Arthur H. Chappelka

Abstract Effects of red maple transplant size [3.8 cm (1.5 in, small) and 7.6 cm (3.0 in, large) trunk diameter] on growth were evaluated at park and residential planting sites in Mobile, AL, during 1993 and 1994. Gas exchange and leaf water potential of transplants were monitored. Small trees had greater shoot elongation than large trees during both growing seasons. In 1994, small trees had greater height increases than large trees. Trunk diameter increases of small transplants were twice those of large transplants in 1994. Photosynthesis, leaf conductance, transpiration, and water use efficiency were higher for small transplants than large transplants on every observation date. In August 1993, pre-dawn and daily leaf water potentials were higher (less negative) for small trees than for large trees.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 601c-601
Author(s):  
Chuhe Chen ◽  
J. Scott Cameron ◽  
Stephen F. Klauer

Leaf water potential (LWP), relative water content (RWC), gas exchange characteristics, and specific leaf weight (SLW) were measured six hours before, during, and after water stress treatment in F. chiloensis and F. ×ananassa grown in growth chambers. The leaves of both species showed significantly lower LWP and RWC as water stress developed. F. ×ananassa had consistency lower LWP under stressed and nonstressed conditions than F. chiloensis. F. ×ananassa had higher RWC under nonstressed conditions, and its RWC decreased more rapidly under water stress than F. chiloensis. In comparison to F. ×ananassa, F. chiloensis had significantly higher CO2 assimilation rate (A), leaf conductance (LC), and SLW, but not transpiration rate (Tr), under stressed and nonstressed conditions. LC was the most sensitive gas exchange characteristic to water stress and decreased first. Later, A and stomatal conductance were reduced under more severe water stress. A very high level of Tr was detected in F. ×ananassa under the most severe water stress and did not regain after stress recovery, suggesting a permanent damage to leaf. The Tr of F. chiloensis was affected less by water stress. Severe water stress resulted in higher SLW of both species.


1976 ◽  
Vol 54 (19) ◽  
pp. 2215-2218 ◽  
Author(s):  
Yoseph Levy ◽  
Merrill R. Kaufmann

Three types of evidence indicate that stomatal cycling occurs in citrus under field conditions. First, dendrograph records collected from 1963 to 1965 on 30-year-old trees revealed daytime oscillations in trunk diameter, with a period of about 1 h. These oscillations occurred during winter and summer months at two southern California locations. Second, leaf conductance measurements were made on 12-year-old citrus in southern California during clear, mild days in March and April, 1975. Oscillations having a period of shorter than 1 h were observed. Third, oscillations in photosynthesis measured with a Shimshi apparatus were observed on 17-year-old citrus in Israel during clear days in November 1975. In controlled greenhouse experiments on 4-year-old citrus in large pots, cycling in leaf conductance, leaf water stress, and trunk diameter were observed, but the patterns differed with root temperatures of 5 and 25 °C. At 5 °C, cycling began early and decreased later in the day, and water stress and trunk diameter changes lagged behind conductance changes. At 25 °C, cycling became more prominent as the day progressed, and no lag was observed.


HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1529-1533 ◽  
Author(s):  
J. Ryan Stewart ◽  
Roger Kjelgren ◽  
Paul G. Johnson ◽  
Michael R. Kuhns

Although transplanted trees typically establish and grow without incident in frequently irrigated turfgrass, their performance in precisely irrigated turfgrass in an arid climate is not known. We investigated the effect of precision irrigation scheduling on growth and water relations of balled-and-burlapped littleleaf linden (Tilia cordata Mill. `Greenspire') planted in buffalograss (Buchloë dactyloides [Nutt.] Engelm. `Tatanka') and kentucky bluegrass (Poa pratensis L.). Over 2 years, trees in turfgrass were irrigated either by frequent replacement based on local reference evapotranspiration, or precision irrigated by estimating depletion of soil water to the point of incipient water stress for each turfgrass species. Predawn leaf water potential and stomatal conductance of trees were measured during first-year establishment, and predawn leaf water potential was measured during a mid-season water-deficit period during the second year. Trunk diameter growth and total tree leaf area were measured at the end of each year. Values of predawn leaf water potential and stomatal conductance of trees in precision-irrigated buffalograss were lower (–0.65 MPa, 25.3 mmol·m–2·s–1) than those of trees in the other treatments near the end of the first growing season. The longer interval between precision irrigations resulted in mild water stress, but was not manifested in growth differences among trees across treatments during the first season. During the water-deficit period of the second year, there was no evidence of stress among the trees regardless of treatment. At the end of the second season, total leaf area of trees grown in precision-irrigated kentucky bluegrass (1.10 ± 0.34 m2) was 46% of that of trees grown in buffalograss (2.39 ± 0.82 m2) that were irrigated frequently. Trunk diameter growth of trees in frequently irrigated kentucky bluegrass (1.91 ± 2.65 mm) was 29% of that of the trees grown in buffalograss (6.68 ± 1.68 mm), regardless of irrigation treatment, suggesting a competition effect from kentucky bluegrass. We conclude that frequent irrigation of balled-and-burlapped trees in turfgrass, particularly buffalograss, is more conducive to tree health during establishment than is maximizing the interval between turfgrass irrigation. Regardless of irrigation schedule, kentucky bluegrass appears to impact tree growth severely during establishment in an arid climate.


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