RAPID MEASUREMENTS OF RELATIVE TURGIDITY IN MAIZE (<i>ZEA MAYS</i> L.)

Downey, Lloyd A.; Miller, J. W.

doi:10.1111/j.1469-8137.1971.tb02557.x

Cited by 17 publications

(14 citation statements)

References 4 publications

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“…Subsequently, the leaves were oven-dried to reach a constant dry weight (DW) at 80 °C. Relative water content (RWC) was calculated according to Downey and Miller33:…”

Section: Methodsmentioning

confidence: 99%

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet

Sun

Zhang

et al. 2015

Sci Rep

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Several auxin herbicides, such as 2, 4-D and dicamba, have been used to eradicate an exotic invasive weed Ipomoea cairica in subtropical China, but restraining the re-explosion of this weed is still a challenge. Since ethylene is one of the major intermediate functioning products during the eradication process, we explored the possibility, mechanism and efficiency of using ethephon which can release ethylene to control Ipomoea cairica. The results of the pot experiment showed that 7.2 g /L ethephon could totally kill Ipomoea cairica including the stems and roots. The water culture experiment indicated that ethephon released an abundance of ethylene directly in leaves and caused increases in electrolyte leakage, 1-aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA) and H2O2 and decreases in chlorophyll content and photosynthetic activity, finally leading to the death of Ipomoea cairica. The field experiment showed that the theoretical effective concentration of ethephon for controlling Ipomoea cairica (weed control efficacy, WCE = 98%) was 4.06 g/L and the half inhibitory concentration (I50) was 0.56 g/L. More than 50% of the accompanying species were insensitive to the phytotoxicity of ethephon. Therefore, ethephon is an excellent alternative herbicide for controlling Ipomoea cairica.

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“…Subsequently, the leaves were oven-dried to reach a constant dry weight (DW) at 80 °C. Relative water content (RWC) was calculated according to Downey and Miller33:…”

Section: Methodsmentioning

confidence: 99%

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet

Sun

Zhang

et al. 2015

Sci Rep

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“…Leaves shrink in their area (Bogue, 1892;Gardner and Ehlig, 1965;Jones, 1973;Tang and Boyer, 2007;Blonder et al, 2012) and, considered in relative terms, even more strongly in their thickness (Fig. 1;Meidner, 1952;Gardner and Ehlig, 1965;Downey and Miller, 1971;Syvertsen and Levy, 1982;Saini and Rathore, 1983;Burquez, 1987;McBurney, 1992;Sancho-Knapik et al, 2010. Leaves fluctuate in thickness daily and seasonally according to transpiration (Kadoya et al, 1975;Tyree and Cameron, 1977;Fensom and Donald, 1982;Rozema et al, 1987;Ogaya and Peñuelas, 2006;Seelig et al, 2012).…”

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confidence: 99%

Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance

et al. 2013

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Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conductance (K leaf ). For 14 diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell and airspace thickness, and leaf area) is associated with reduction in K leaf at declining leaf water potential (C leaf ). We tested hypotheses for the linkage of leaf shrinkage with structural and physiological water relations parameters, including modulus of elasticity, osmotic pressure at full turgor, turgor loss point (TLP), and cuticular conductance. Species originating from moist habitats showed substantial shrinkage during dehydration before reaching TLP, in contrast with species originating from dry habitats. Across species, the decline of K leaf with mild dehydration (i.e. the initial slope of the K leaf versus C leaf curve) correlated with the decline of leaf thickness (the slope of the leaf thickness versus C leaf curve), as expected based on predictions from computer simulations. Leaf thickness shrinkage before TLP correlated across species with lower modulus of elasticity and with less negative osmotic pressure at full turgor, as did leaf area shrinkage between full turgor and oven desiccation. These findings point to a role for leaf shrinkage in hydraulic decline during mild dehydration, with potential impacts on drought adaptation for cells and leaves, influencing plant ecological distributions.

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“…However, this would require that RWC could be reliably estimated from the prior weights: sampling weight, turgid weight, or the difference, water uptake. Downey and Miller (3) have determined an empirical relationship between RWC and water uptake for maize, using small discs of constant area.…”

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confidence: 99%

“…Northern Spy) (0.997) using a range of leaf ages. The proposal by Downey and Miller (1971. Rapid measurements of relative turgidity in maize (Zea mays L.). New Phytol.…”

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confidence: 99%

Rapid Estimates of Relative Water Content

Smart¹,

Bingham²

1974

Plant Physiol.

647

252

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Relative water content may be accurately estimated using the ratio of tissue fresh weight to tissue turgid weight, termed here relative tissue weight. That relative water content and relative tissue weight are linearly related is demonstrated algebraically. The mean value of r2 for grapevine (Vitis vinifera L. cv. Shiraz) leaf tissue over eight separate sampling occasions was 0.993. Similarly high values were obtained for maize (Zea mays cv. Cornell M-3) (0.998) and apple (Malus sylvestris cv. Northern Spy) (0.997) using a range of leaf ages. The proposal by Downey and Miller (1971. Rapid measurements of relative turgidity in maize (Zea mays L.). New Phytol. 70: 555-560) that relative water content in maize may be estimated from water uptake was also investigated for grapevine leaves; this was found to be a less reliable estimate than that obtained with relative tissue weight. With either method, there is a need for calibration, although this could be achieved for relative tissue weight at least with only a few subsamples.The relative water content technique, formerly known as relative turgidity, was originally described by Weatherley (9, 10) and has been widely accepted as a reproducible and meaningful index of plant water status (see literature cited by Barrs [1] monly expressed in decimal form (5, 11), and this convention is followed here.A major disadvantage of the RWC technique is the considerable time lag between sampling and obtaining the result. Further, the four weighing operations required (one for tare weight) are time-consuming and monotonous. These objections could be partly overcome if the oven-drying operation and subsequent weighing operation could be eliminated. However, this would require that RWC could be reliably estimated from the prior weights: sampling weight, turgid weight, or the difference, water uptake. Downey and Miller (3) have determined an empirical relationship between RWC and water uptake for maize, using small discs of constant area.A second indirect estimate of RWC is introduced here. This index, termed relative tissue weight, is calculated as the ratio tissue fresh weight to turgid weight. The same ratio has been used before (4,7,8), but in all three instances it has been termed erroneously relative turgidity. MATERIALS AND METHODSGrapevines (Vitis vinifera L. cv. Shiraz) growing in an irrigation trial at the Griffith Viticultural Research Station, N.S.W. provided a range of leaf material of varying water status. Two replicates of eight treatments were sampled on each of 2 consecutive days on eight occasions throughout the growing season of 1968-69. The youngest fully expanded leaf was used. Four leaf samples were taken from each plot of four adjacent vines between 6 AM and 6:30 AM EST, sealed in plastic bags, and taken to the laboratory. There an entire disc of 8.4 cm diameter was cut from each leaf. Discs of this size were found to give considerably less variable RWC values than samples of 20 discs of diameter 0.8 cm, as recommended by Barrs (1); RWC values for th...

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RAPID MEASUREMENTS OF RELATIVE TURGIDITY IN MAIZE (ZEA MAYS L.)

Cited by 17 publications

References 4 publications

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet

Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance

Rapid Estimates of Relative Water Content

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