Glasshouse and field studies on the effects of groundcovers on banana and macadamia growth and water relations

2003 ◽  
Vol 43 (10) ◽  
pp. 1245 ◽  
Author(s):  
D. J. Firth ◽  
G. G. Johns ◽  
R. D. B. Whalley
Keyword(s):  
Adverse Effect ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Status ◽  
Field Studies ◽  
Bare Soil ◽  
Soil Bulk Density ◽  
Early Morning ◽  
Xylem Water Potential ◽  
Penetrometer Resistance

Groundcovers can be useful for controlling erosion in macadamia orchards but they can have adverse effects on tree growth and crop yield. The effects of groundcovers versus bare soil on banana and macadamia were compared in a glasshouse study and on macadamia in the field. A glasshouse trial compared the effect of 3 water regimes with unmown or mown Arachis pintoi cv. Amarillo groundcover versus bare soil, on stomatal conductance and growth of banana and macadamia. Mean stomatal conductance was higher overall for macadamia (178 mmol/m2.s) compared with banana (90 mmol/m2.s) when data were pooled across groundcover and water treatments. Medium and dry substrate moisture treatments significantly reduced the growth and vigour of banana compared with the wet treatments, as indicated by reduced total dry matter, leaf area, number of live leaves at harvest, and total root length, but had no significant effect on macadamia. Groundcover had a more adverse effect on the growth of banana than macadamia compared with bare soil and, likewise, unmown cover had a greater effect on growth of banana than mown cover, while there was no mowing effect on macadamia.In an unirrigated field trial, mown and unmown groundcover and bare soil treatments were compared for their effect on early morning leaf xylem water potential of young and older macadamia trees at 3 sites where groundcover was established at different tree ages. Water potential was generally <0.2 MPa more negative in the groundcover treatment than bare soil in spring and summer under dry seasonal conditions over 2 years, although there was no apparent effect on tree health. The difference in water potential between groundcover and bare soil was highest in young trees planted in established groundcover. The more adverse effect of groundcover on water status of young trees in established cover correlates with a greater reduction in growth compared with older trees reported separately (Firth et al. 2003 Aust. J. Exp. Agric. 43, 419–423).Soil bulk density under groundcover was slightly reduced (0.028 g/cm3) at 0–10 cm depth, and penetrometer resistance also slightly reduced (<0.3 MPa) at 0–12 cm depth, compared with bare soil. Higher penetrometer readings in the traffic zone (often >4 MPa at 30–40 cm in the initial survey) compared with the tree line indicate the potential long-term benefits to be derived from groundcovers.

Relationship Between Root/Soil Hydraulic Properties and Stomatal Behaviour in Sugarcane

1989 ◽  
Vol 16 (3) ◽  
pp. 241 ◽  
Author(s):  
NZ Saliendra ◽  
FC Meinzer
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Soil Drying ◽  
Root Hydraulic Conductance ◽  
High Soil Moisture

Stomatal conductance, leaf and soil water status, transpiration, and apparent root hydraulic conductance were measured during soil drying cycles for three sugarcane cultivars growing in containers in a greenhouse. At high soil moisture, transpiration and apparent root hydraulic conductance differed considerably among cultivars and were positively correlated, whereas leaf water potential was similar among cultivars. In drying soil, stomatal and apparent root hydraulic conductance approached zero over a narrow (0.1 MPa) range of soil water suction. Leaf water potential remained nearly constant during soil drying because the vapor phase conductance of the leaves and the apparent liquid phase conductance of the root system declined in parallel. The decline in apparent root hydraulic conductance with soil drying was manifested as a large increase in the hydrostatic pressure gradient between the soil and the root xylem. These results suggested that control of stomatal conductance in sugarcane plants exposed to drying soil was exerted primarily at the root rather than at the leaf level.

Effect of Water Stress on Stomatal Conductance and Leaf Water Relations of Leaves Along Current-Year Branches of Peach

1989 ◽  
Vol 16 (6) ◽  
pp. 549 ◽  
Author(s):  
SL Steinberg ◽  
MJ Mcfarland ◽  
JC Miller
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Water Flux ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Mature Leaves ◽  
Water Potentials

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.

scholarly journals Leaf water potentials of sunlit and/or shaded grapevine leaves are sensitive alternatives to stem water potential

OENO One ◽  
2012 ◽  
Vol 46 (3) ◽  
pp. 207
Author(s):  
Larry E. Williams
Keyword(s):  
Stomatal Conductance ◽  
Solar Radiation ◽  
Water Potential ◽  
Water Status ◽  
Direct Solar Radiation ◽  
Cabernet Sauvignon ◽  
Direct Sunlight ◽  
Water Potentials ◽  
Significant Difference ◽  
Highly Correlated

<p style="text-align: justify;"><strong>Aims</strong>: Leaf (Ψ<sub>l</sub>) and stem (Ψ<sub>stem</sub>) water potentials were measured on grapevines to determine the effects of shoot location on both methods to assess vine water status.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Cabernet-Sauvignon and Merlot used in this study were grown at two locations in California. Measurements were taken at midday in July (Merlot) and at two times of the day (morning and afternoon), on two dates in August (Cabernet- Sauvignon). Measurements of Ψ<sub>l</sub> and Ψ<sub>stem</sub>, stomatal conductance and transpiration were taken on shoots entirely exposed to direct solar radiation or on shoots totally in the shade at the times of measurement. There were significant differences (<em>P</em> &lt; 0.05) between Ψ<sub>l</sub> and/or Ψ<sub>stem</sub> measured on shoots exposed to direct solar radiation and those in the shade. Both Ψ<sub>l</sub> and Ψ<sub>stem</sub> were significantly greater on the shoots exposed to direct sunlight compared to those in the shade. There was no significant difference between Ψ<sub>l</sub> measured on shaded leaves and Ψ<sub>stem</sub> determined on the fully exposed shoots.</p><p style="text-align: justify;"><strong>Conclusions</strong>: Regardless of method used, water potentials were highly correlated with stomatal conductance measured on leaves in direct sunlight at the same time. All means of measuring grapevine water potential used in this study were highly correlated with one another.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The data indicate that any of the techniques used in this study would be a sensitive indicator of vine water status and that the Ψ of shaded leaves would be an alternative to the measurement of Ψ<sub>stem</sub>.</p>

Supplementary Irrigation of Young Clonal Tea in Kenya. II. Internal Water Status

1978 ◽  
Vol 14 (4) ◽  
pp. 309-316 ◽  
Author(s):  
C. O. Othieno
Keyword(s):  
Water Potential ◽  
Camellia Sinensis ◽  
Water Status ◽  
Xylem Water Potential ◽  
Internal Water ◽  
Supplementary Irrigation ◽  
Dry Seasons ◽  
Tea Plants ◽  
Wet And Dry Seasons

SUMMARYMeasurements of the stomatal apertures of young clonal tea plants (Camellia sinensis) showed that stomata of plants irrigated during the dry seasons only were wider open than those not irrigated during both wet and dry seasons. Similarly, xylem water potential values (ψx) were always higher (less negative) in irrigated than non-irrigated plants, during both wet and dry seasons. The results suggest that more drought-susceptible clones have a greater demand for water than those less susceptible to drought.

scholarly journals Variation in scion water relations mediated by two newly released Geneva series rootstocks

2021 ◽  
Author(s):  
Erica Casagrande Biasuz ◽  
Lee Kalcsits
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Relations ◽  
Isotope Composition ◽  
Water Status ◽  
Physiological Traits ◽  
Stem Water Potential ◽  
Carbon And Oxygen Isotope ◽  
Stem Water

Dwarfing rootstocks are used to control tree vigor allowing for increased densities that increase apple production. Although there is considerable variation among rootstocks in dwarfing capacity, the mechanisms by which rootstocks affect vigor in apple scions remains unclear. Here, Honeycrisp apple growth and water relations were compared among three rootstocks; M-9 as the industry standard and two less studied Geneva series rootstocks; G.87 and G. 814 in Washington, USA. Trees were acquired from a commercial nursery and planted in 2017. In 2018 and 2019, scion physiological, isotopic and morphological traits were measured to better understand the link between rootstock-driven vigor and physiological traits. Rootstock affected scion shoot growth (P <0.001), stomatal conductance (P< 0.01) and stem water potential (P <0.001). Rootstocks with low vegetative vigor like M.9 also had lower stomatal conductance and enriched leaf δ13C and δ18O isotope composition. Plant growth was positively correlated with stomatal conductance and stem water potential. Rootstocks also affected plant water status and net gas exchange. Here, we report an association between rootstock-induced vigor and scion physiological traits such as gas exchange, stem water potential, and leaf carbon and oxygen isotope composition. This research has implications for the understanding of the mechanisms of dwarfing by rootstocks in apple.

scholarly journals EXTRACTS FROM ASH ROOTS AND VELVETLEAF AFFECT WATER STATUS OF SOUR ORANGE SEEDLINGS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 579b-579
Author(s):  
John E. Fucik ◽  
Dariusz Swietlik
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Absorption ◽  
Water Potential ◽  
Plant Material ◽  
Water Status ◽  
Culture Solution ◽  
Sour Orange ◽  
Growth Responses ◽  
Water Culture

Water extracts of cocklebur,CBX (Xanthium spinosa L.) and velvetleaf,VLX (Abutilon theophrasti Medic.) shoots and Mexican ash,AshX (Fraxinus Berlandieriana A.DC.) roots were added to 9 month-old sour orange Citrus aurantium L.) seedlings(SOs) in water culture. Final extract concentrations represented either 50 or 12.5 g. of plant material liter-1 of culture solution, i.e. 1/20 or 1/80 dilutions. Leaf water potential(ψ); stomatal conductance(gs);transpiration(T) and growth responses were measured for 13 days. After 1 day, SOs in AshX and CBX had lower ψ than controls. After 11 days SOs in CBX had higher ψ than the others. ψ responded similarly to both extract concs.. Thru day 5, AshX decreased gs vs. the controls and VLX. By day 11, gs of SOs in AshX was less than for VLX but not the others. On days 1 and 5, gs for VLX at 1/20 was lower than controls but at 1/80, gs's were the highest of all treatments. These results supported by the T rates, growth responses and others findings suggest AshX and VLX induce water stress by reducing water absorption and/or transport in addition to possibly disrupting normal root/shoot communications

scholarly journals Water Stress Patterns of Xerophytic Plants in an Urban Landscape

HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 818-823 ◽  
Author(s):  
Richard Martinson ◽  
John Lambrinos ◽  
Ricardo Mata-González
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Use ◽  
Management Practices ◽  
Urban Landscape ◽  
Water Status ◽  
Arid Environment ◽  
Irrigation Scheduling ◽  
Urban Landscapes ◽  
Xylem Water Potential

Efficient water use in urban landscapes is a common objective throughout the western United States. Vegetative species promoted for their drought tolerance characteristics are often included in landscapes designed for resource conservation. However, water requirements of most common landscape species have not been quantified. This is especially true for xerophytic species. This lack of landscape plant water requirement data is a significant constraint on the design of efficient irrigation systems and management practices affecting urban landscape water use. Current irrigation practices often fail to consider the unique physiology of xerophytic species, and irrigation scheduling models may not be appropriate for xeric landscapes using xerophytic vegetation as the primary method of reducing water use. This work describes the seasonal patterns of growth and xylem water status for four regionally native xeric shrub species planted in an unirrigated urban landscape in the semi-arid environment of central Oregon. The four species (Artemisia tridentata, Holodiscus microphyllus, Ericameria nauseosa, and Ribes cereum) exhibited substantial growth over the course of 18 months without irrigation in a heavily modified urban soil profile. Water potential of the four species was strongly correlated with surface (10 cm) soil moisture (r ≥ 0.90), less so with reference monthly evapotranspiration (r ≤ 0.55), and only weakly with water vapor deficit (r ≤ 0.22). In A. tridentata and H. microphyllus, xylem water potential became more negative during the growing season and tracked the seasonal decline in soil moisture. In contrast, the xylem water potential of E. nauseosa and R. cereum tracked soil moisture early in the season but became less responsive to soil moisture in the driest months, suggesting different drought adaptation strategies in these species. Three of the four species showed no visual signs of drought stress and maintained acceptable aesthetics even as soil moisture decreased to less than 10%. However, R. cereum exhibited a drought dormancy strategy that made it less aesthetically desirable. These results suggest that extreme xerophytic shrubs provide an opportunity for significant reductions in water use in urban landscapes.

Stomatal Responses and Whole-Tree Hydraulic Conductivity of Orchard Macadamia integrifolia Under Irrigated and Non-Irrigated Conditions

1991 ◽  
Vol 18 (6) ◽  
pp. 661 ◽  
Author(s):  
J Lloyd ◽  
T Trochoulias ◽  
R Ensbey
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Simple Expression ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Diurnal Patterns ◽  
Macadamia Integrifolia ◽  
Independent Variable

Diurnal patterns of stomatal conductance (gs) and leaf water potential (Ψ1) were determined for leaves on irrigated and non-irrigated 5-year-old Macadamia integrifolia trees over a 4-month period from September to December 1989. An empirical model for stomatal conductance was developed for irrigated trees using relationships to photon irradiance (I), leaf temperature (T1) and vapour mole fraction difference (D). This model accounted for 69% of the variance in gs, and was not improved by the inclusion of Ψ1 as an independent variable. Fitted parameters led to the effective prediction of gs for untried combinations of environmental variables. By using a simple expression to link leaf water potential to transpiration rate (E), the model was extended to prediction of Ψ1 from measurements of I, T1 and D. Stornatal conductances were significantly lower on non-irrigated trees after a 2-month dry period. Lower stornatal conductances were not accompanied by more negative Ψ1 indicating that soil rather than leaf water status may control gs in macadamia trees under non-irrigated conditions.

Response to water stress of Italian alder seedlings from diverse geographic origins

1989 ◽  
Vol 19 (8) ◽  
pp. 1071-1076 ◽  
Author(s):  
M. Borghetti ◽  
S. Cocco ◽  
M. Lambardi ◽  
S. Raddi
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Leaf Area ◽  
Water Status ◽  
Net Photosynthesis ◽  
Severe Drought ◽  
Xylem Water Potential ◽  
Drought Treatment ◽  
Internal Water ◽  
Response To Water

The morphological and physiological response to water stress was studied in 2-year-old potted Italian alder (Alnuscordata Loisel.) seedlings. Leaf area, transpiration, stomatal conductance, and xylem water potential were measured during May 1987 on seedlings from five geographic sources grown (i) with soil water content close to field capacity and (ii) with a severe drought. Significant differences in leaf area were found, at the end of the experiment, between drought-stressed and well-watered plants. As drought progressed, plants displayed a reduction of xylem water potentials and a decrease in stomatal conductance. However, transpiration did not stop completely, and seedlings were not able to maintain a favourable internal water status. Osmotic potentials for the undiluted cell sap, estimated from pressure–volume curves, were between −0.9 and −1.3 MPa. In June 1988, a similar experiment was carried out using seedlings from only one geographic source. A simultaneous decrease of transpiration, xylem potential, and net photosynthesis was observed in seedlings subjected to the drought treatment. During both experiments, a recovery of physiological parameters was observed, after rewatering. Some differences between provenances were detected. The provenance from Corsica showed the greatest sensitivity to water stress; a seed source from the province of Avellino (Campania, south Italy) was able to maintain a more favourable internal water status, as drought progressed.

Sign in / Sign up

Export Citation Format

Share Document