Calcium Uptake and Whole-plant Water Use Influence Pod Calcium Concentration in Snap Bean Plants

Understanding the mechanisms that regulate xylem transport of calcium (Ca) to snap bean (Phaseolus vulgaris L.) pods could allow approaches to increase pod Ca concentration and enhance the nutritional value of edible pods. Using the snap bean cultivars Hystyle and Labrador, which exhibit high and low pod Ca levels, respectively, we wished to determine whether there were differences between the two cultivars in stem xylem-sap Ca concentration and whether any differences in sap Ca concentration were related to differences in whole-plant water uptake or Ca import between the cultivars. Well-watered greenhouse-grown plants were placed in a growth chamber at a constant light intensity for an equilibration period. Pot weight loss was measured to determine whole-plant water use and stem xylem exudate was subsequently collected from the severed base of the shoot at flowering and at two stages of pod development. `Hystyle' displayed an exudate Ca concentration that was 50% higher than `Labrador' during pod development. `Labrador' showed 35% greater total water transport through the stem than `Hystyle'. `Labrador' plants also showed a significantly larger leaf area than `Hystyle' plants. Additional plants were used to determine total, long-term Ca influx. No difference was observed between cultivars in total Ca influx into the aerial portion of the plant. With whole-shoot Ca influx being equivalent and pod transpiration rate identical in the two cultivars, our results suggest that the higher whole-plant water uptake in `Labrador' led to a dilution of Ca concentration in the xylem stream and thus less total Ca was transported to developing pods, relative to that in `Hystyle'. Increased transpiration efficiency, enhanced root uptake of Ca, or reduced Ca sequestration in the xylem pathway of the stem could lead to an enhancement in pod Ca concentration in future cultivars of snap bean.

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Calcium Uptake and Whole-plant Water Use Influence Pod Calcium Concentration in Green Bean Plants

HortScience ◽

10.21273/hortsci.33.3.542d ◽

1998 ◽

Vol 33 (3) ◽

pp. 542d-542

Author(s):

Kirk W. Pomper ◽

Michael A. Grusak

Keyword(s):

Water Use ◽

Water Uptake ◽

Xylem Sap ◽

Green Bean ◽

Plant Water ◽

Plant Water Use ◽

Whole Plant ◽

Ca Uptake ◽

Pod Development ◽

Two Stages

Understanding the mechanisms that regulate xylem transport of calcium (Ca) to green bean pods could allow approaches to increase pod Ca concentrations and enhance the nutritional value of edible pods. Using the green bean cultivars `Hystyle' and `Labrador', that exhibit high and low pod Ca levels respectively, we wished to determine whether observed differences in Ca concentration of stem xylem-sap were related to differences in whole-plant water uptake and Ca import. Well-watered greenhouse-grown plants, selected at flowering and at two stages of pod development, were placed in a growth chamber at a constant light intensity. Pot weight loss was measured to determine whole-plant water use and stem xylem exudate was subsequently collected from the severed base of the shoot. `Hystyle' displayed 50% higher Ca concentration in exudate than `Labrador' during pod development. Labrador showed 35% greater total water transport through the stem than `Hystyle'. Additional plants were used to determine total, long-term Ca uptake. No significant differences in total Ca were seen between cultivars at the three harvest dates. With whole-plant Ca uptake being equivalent, the results suggest that higher water uptake in `Labrador' led to a dilution of Ca in the xylem stream and thus less total Ca was transported to developing pods, relative to that in `Hystyle'. These results reveal that green bean varieties with low whole-plant water use have the potential to yield edible pods with elevated Ca content.

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Soil moisture heterogeneity regulates water use in Populus nigra L. by altering root and xylem sap phytohormone concentrations

Tree Physiology ◽

10.1093/treephys/tpaa037 ◽

2020 ◽

Vol 40 (6) ◽

pp. 762-773 ◽

Cited By ~ 1

Author(s):

Jaime Puértolas ◽

Marta Pardos ◽

Carlos de Ollas ◽

Alfonso Albacete ◽

Ian C Dodd

Keyword(s):

Soil Moisture ◽

Water Use ◽

Deficit Irrigation ◽

Xylem Sap ◽

Irrigation Scheduling ◽

Populus Nigra ◽

Soil Drying ◽

Plant Water ◽

Plant Water Use ◽

Soil Moisture Heterogeneity

Abstract Soil moisture heterogeneity in the root zone is common both during the establishment of tree seedlings and in experiments aiming to impose semi-constant soil moisture deficits, but its effects on regulating plant water use compared with homogenous soil drying are not well known in trees. Pronounced vertical soil moisture heterogeneity was imposed on black poplar (Populus nigra L.) grown in soil columns by altering irrigation frequency, to test whether plant water use, hydraulic responses, root phytohormone concentrations and root xylem sap chemical composition differed between wet (well-watered, WW), and homogeneously (infrequent deficit irrigation, IDI) and heterogeneously dry soil (frequent deficit irrigation, FDI). At the same bulk soil water content, FDI plants had greater water use than IDI plants, probably because root abscisic acid (ABA) concentration was low in the upper wetter layer of FDI plants, which maintained root xylem sap ABA concentration at basal levels in contrast with IDI. Soil drying did not increase root xylem concentration of any other hormone. Nevertheless, plant-to-plant variation in xylem jasmonic acid (JA) concentration was negatively related to leaf stomatal conductance within WW and FDI plants. However, feeding detached leaves with high (1200 nM) JA concentrations via the transpiration stream decreased transpiration only marginally. Xylem pH and sulphate concentration decreased in FDI plants compared with well-watered plants. Frequent deficit irrigation increased root accumulation of the cytokinin trans-zeatin (tZ), especially in the dry lower layer, and of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), in the wet upper soil layer. Root hormone accumulation might explain the maintenance of high root hydraulic conductance and water use in FDI plants (similar to well-watered plants) compared with IDI plants. In irrigated tree crops, growers could vary irrigation scheduling to control water use by altering the hormone balance.

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From leaf to whole-plant water use efficiency (WUE) in complex canopies: Limitations of leaf WUE as a selection target

The Crop Journal ◽

10.1016/j.cj.2015.04.002 ◽

2015 ◽

Vol 3 (3) ◽

pp. 220-228 ◽

Cited By ~ 181

Author(s):

Hipólito Medrano ◽

Magdalena Tomás ◽

Sebastià Martorell ◽

Jaume Flexas ◽

Esther Hernández ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Plant Water ◽

Plant Water Use ◽

Whole Plant ◽

Use Efficiency

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Water Use of Hydrangea macrophylla and Gardenia jasminoides in Response to a Gradually Drying Substrate

HortScience ◽

10.21273/hortsci.49.4.493 ◽

2014 ◽

Vol 49 (4) ◽

pp. 493-498 ◽

Cited By ~ 5

Author(s):

Lucas O’Meara ◽

Matthew R. Chappell ◽

Marc W. van Iersel

Keyword(s):

Hydraulic Conductivity ◽

Water Use ◽

Water Uptake ◽

Hydraulic Properties ◽

Plant Water ◽

Plant Water Uptake ◽

Available Water ◽

Gardenia Jasminoides ◽

Hydrangea Macrophylla ◽

Plant Available Water

As a result of the lack of quantitative data regarding specific water requirements of ornamental species, precision irrigation can be a difficult task for nursery growers. One challenge for growers is that it is not clear how much of the water in soilless substrates is actually available for plant uptake. Substrate moisture release curves (MRC) have been used to predict the amount of plant-available water in soilless substrates, yet there is little information about whether there are differences among species in their ability to extract water from substrates. The objectives of this study were to determine 1) the hydraulic properties of a composted pine bark substrate; and 2) how water uptake in Hydrangea macrophylla and Gardenia jasminoides was affected by decreasing substrate volumetric water content (VWC). As the substrate VWC decreased from 0.38 to 0.17 m3·m−3, substrate matric potential decreased from –4.0 to –69 kPa, whereas hydraulic conductivity decreased from 0.115 to 0.000069 cm·d−1. To measure plant water uptake in a drying substrate, growth chambers were used to provide stable environmental conditions that included continuous lighting to prevent diurnal fluctuations in water use. Water use by H. macrophylla ‘Fasan’ started to decrease at a higher VWC (0.28 m3·m−3) than G. jasminoides ‘Radicans’ (0.20 m3·m−3). Plant water uptake stopped at a VWC of 0.16 m3·m−3 in H. macrophylla and 0.12 m3·m−3 in G. jasminoides. The results show that H. macrophylla is less adept at extracting water from a drying substrate than G. jasminoides. Traditionally, plant-available water in soilless substrates has been studied using substrate MRCs. Our data suggest that substrate hydraulic conductivity may be an important factor controlling water availability to the plants. In addition, there are important differences among species that cannot be detected by only looking at substrate hydraulic properties.

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