Inherent variability in structural and functional traits of xylem among three hop varieties

Jupa, Radek; Baláž, Milan; Svoboda, P.; Gloser, Vít

doi:10.17221/32/2013-pse

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…In fact, during the preparation of this manuscript we evaluated 18 published reviews on transgenic and breeding efforts to improve drought tolerance in crops, and not a single report includes the word "xylem" or addresses water transport (Gleason, 2015). This may be because little heritable variation in xylem traits has been found (Jupa et al, 2013;Lamy et al, 2011;Lamy et al, 2014;Rosner et al, 2007;Wortemann et al, 2011). Nevertheless, hydraulic resistance in xylem tissue remains a significant component of whole plant resistance (Nardini and Salleo, 2000;Sack et al, 2003), and as such, is a common source of hydraulic failure and death during drought stress (Choat, 2013;Lens et al, 2013;Rowland et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Coordinated decline in photosynthesis and hydraulic conductance during drought stress in Zea mays

Gleason

Wiggans

Bliss

et al. 2017

Flora

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Present efforts to improve maize performance in water-limited environments are aggressively pursuing leaf-level traits, such as quantum efficiency, mesophyll osmoregulation, and stress-protein responses.However, it is possible that improvement of these traits will lead directly to hydraulic failure if hydraulics and photosynthesis are closely aligned. Here, we address the whole plant response to drought stress and ask if photosynthetic and hydraulic traits appear bundled together as a "coordinated" response, or if these traits operate largely independently of one another. Xylem conductance of leaves and stems, whole plant conductance, stomatal conductance, rate of electron transport (ETR), maximal catalytic rate of phosphoenolpyruvate carboxylase (V pmax ) (EC 4.1.1.31), and net CO 2 assimilation (A max ) were measured in maize plants subjected to contrasting levels of drought stress in greenhouse and field experiments. Photosynthetic traits (A max , ETR, V pmax ), hydraulic traits (whole plant and stem conductance) and stomatal conductance were all reduced by > 80% as leaf water potentials declined below -3.0 MPa. Furthermore, 83% of the variation associated with the photosynthetic and hydraulic traits measured in this study was © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ explained by a single principal component, revealing a remarkable degree of alignment among them.Whole plant transpiration rates recovered to ca 90% of maximal values 4 d after lifting severe drought stress (Ψ leaf ≈ -3.5 MPa). Closely aligned hydraulic, photosynthetic, and stomatal responses to drought stress suggest that improvements to individual traits, in isolation to each other, may lead to the loss of plant functioning (e.g. water transport) rather than leading to marked improvements in growth.

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Section: Introductionmentioning

confidence: 99%

Coordinated decline in photosynthesis and hydraulic conductance during drought stress in Zea mays

Gleason

Wiggans

Bliss

et al. 2017

Flora

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“…Comparisons of K ht with experimentally measured K h typically indicate great differences, as presented in many previous studies (Martre et al, 2000 ; Gloser et al, 2011 ; Jupa et al, 2013 ). Factors such as the resistivity of vessel end walls (Sperry et al, 2005 ) or perforation plates (Christman and Sperry, 2010 ), deviations from the shape of the ideal capillary, the variation in vessel diameter, or the incorrect determination of conductive vessels contribute most to the total difference.…”

Section: Discussionmentioning

confidence: 75%

“…In several studies, the histochemical staining of cross sections by toluidine blue or acidified phloroglucinol was used for the identification of conductive elements with lignified secondary cell walls (Chaffey et al, 2002 ; Jupa et al, 2013 ). However, the degree of lignification is not a reliable marker for the identification of fully functional elements.…”

Section: Introductionmentioning

confidence: 99%

An improved method for the visualization of conductive vessels in Arabidopsis thaliana inflorescence stems

et al. 2015

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Dye perfusion is commonly used for the identification of conductive elements important for the study of xylem development as well as precise hydraulic estimations. The tiny size of inflorescence stems, the small amount of vessels in close arrangement, and high hydraulic resistivity delimit the use of the method for quantification of the water conductivity of Arabidopsis thaliana, one of the recently most extensively used plant models. Here, we present an extensive adjustment to the method in order to reliably identify individual functional (conductive) vessels. Segments of inflorescence stems were sealed in silicone tubes to prevent damage and perfused with a dye solution. Our results showed that dyes often used for staining functional xylem elements (safranin, fuchsine, toluidine blue) failed with Arabidopsis. In contrast, Fluorescent Brightener 28 dye solution perfused through segments stained secondary cell walls of functional vessels, which were clearly distinguishable in native cross sections. When compared to identification based on the degree of development of secondary cell walls, identification with the help of dye perfusion revealed a significantly lower number of functional vessels and values of theoretical hydraulic conductivity. We found that lignified but not yet functional vessels form a substantial portion of the xylem in apical and basal segments of Arabidopsis and, thus, significantly affect the analyzed functional parameters of xylem. The presented methodology enables reliable identification of individual functional vessels, allowing thus estimations of hydraulic conductivities to be improved, size distributions and vessel diameters to be refined, and data variability generally to be reduced.

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High sensitivity of hop plants (Humulus lupulus L.) to limited soil water availability: the role of stomata regulation and xylem vulnerability to embolism

Gloser,

Baláž,

Svoboda

et al. 2024

Irrig Sci

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Drought poses a serious threat to the productivity of hop, an important perennial crop. However, the precise physiological mechanisms that make it highly susceptible to drought are not yet fully understood. In this study, we investigated stomatal regulation and xylem vulnerability to embolism, which are important traits closely associated with plant drought resistance. In a glasshouse cultivation experiment, we monitored changes in leaf water potential, stem elongation rates, and leaf gas exchange, including net photosynthetic rates, stomatal conductance, and intrinsic water use efficiency, on relatively young hop plants (traditional Saaz - Osvald’s clone 31) exposed to declining soil water availability. The transpiration rate and stem elongation of plants decreased significantly with a small decline in substrate water potential (ΨSUB), indicating a highly sensitive stomata response during early phases of soil dehydration. The stem elongation was completely halted, and the transpiration rate dropped to less than 50% of its maximum at ΨSUB levels below − 0.8 MPa. In well-watered hop plants, xylem in stems operates near the initial point of embolization and is highly vulnerable to embolism, with a water potential corresponding to a 50% loss of xylem conductivity at -1.6 MPa. The sensitive stomatal response to declining ΨSUB likely helps to mitigate the risk of hydraulic failure, albeit at the cost of impaired growth. Scheduled irrigation, particularly during the sensitive stem elongation stage, may be a promising approach to mitigate the detrimental effects of reduced soil water availability on hop growth and yield while also conserving water resources.

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Inherent variability in structural and functional traits of xylem among three hop varieties

Cited by 6 publications

References 17 publications

Coordinated decline in photosynthesis and hydraulic conductance during drought stress in Zea mays

Coordinated decline in photosynthesis and hydraulic conductance during drought stress in Zea mays

An improved method for the visualization of conductive vessels in Arabidopsis thaliana inflorescence stems

High sensitivity of hop plants (Humulus lupulus L.) to limited soil water availability: the role of stomata regulation and xylem vulnerability to embolism

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