Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomat... more The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomato (Lycopersicon esculentum Mill. cv. Sprinter) fruit cuti cles. Both cuticular membranes (CM) and dewaxed CM (DCM) sorbed more NAA at pH 2.2 than at pH 6.2. A t each pH, increasing temperature (15° to 35°C) decreased NAA sorption by both CM and DCM. The same qualitative temperature (5° to 25°) response was observed with 2,4-D for CM at low (0.8) pH. Chemical names used: 2-(l-naphthyl)acetic acid (NAA); (2,4-dichlorophenoxy)acetic acid (2,4-D). H o r t S c i e n c e 23(l):204-206. 1988. Foliar absorption of an applied substance is a multistep process governed by both physical and biological factors. Environ mental and/or solution characteristics (e.g., temperature, pH) at the time of application can have a profound effect on this complex process (7, 8 , 18). Typically, for weak or ganic acid auxins, absorption increases with increasing temperature and/or decreasing pH. The plant cuticle is the initial and primary barrier to foliar absorption (2, 5). Transfer across the cuticle occurs by sorption into the cuticular membrane, diffusion through and desorption from the cuticle on the cell wall side. Therefore, in an effort to further elu cidate the effects of temperature and pH on absorption, we used isolated tomato fruit cu ticles as a model cuticle and NAA and 2,4-D as model weak organic acid auxins. To mato fruit cuticle was selected because con siderable inform ation is available on its composition, structure, and permeability characteristics . NAA and 2,4-D were selected because they are im portant agrochemical representatives of the weak organic acid auxins. In these studies we focused on sorption because it represents an important early process in cuticular pen-
Asparagus (A sp a r a g u s o ffic in a lis L.) root tissue added to soil at 2, 4, or 6 g (dry we... more Asparagus (A sp a r a g u s o ffic in a lis L.) root tissue added to soil at 2, 4, or 6 g (dry weight basis) per 100 g of dry soil generally inhibited lettuce and delayed tomato and asparagus seedling emergence when incorporated in soil for 0 or 28 days before seeding. The toxicity of the 2 and 4 g rates of asparagus root tissue was diminished after 50 days, but the 6 g rate inhibited and/or delayed emergence 50 and 90 days after incorporation in soil. These results suggest that asparagus root tissues contain a heteroand auto-toxic allelopathic compound(s) that is inactivated with increasing time in the soil. In recent years many asparagus plantings in New Jersey have experienced a decrease in plant vigor, and this has previously been attributed to a Fusarium root, stem, and crown rot complex (2, 3). Some evidence now sug gests that allelopathy, the process whereby a chemical compound (phytotoxin) is re leased into the soil environment by 1 plant and inhibits the growth of a neighboring plant (6 , 7), also may be involved in asparagus decline. The presence of an allelopathic sub stance^) in asparagus roots grown under both field (1, 4, 10) and aseptic (10) conditions recently has been confirmed. No information was obtained from these studies on the effect of increasing amounts of tissue in the soil, nor on the persistence of the toxic effect in the soil. The following experiments therefore were designed to ex amine the effect of increasing amounts of asparagus root tissue present in a soil envi ronment and the duration of that toxicity un der defined conditions. Asparagus plants were raised in a nursery in Salem County, New Jersey, on a soil with no history of asparagus planting or herbicide usage. Five-month old plants were harvested at the end of the growing season, and only
The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomat... more The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomato (Lycopersicon esculentum Mill. cv. Sprinter) fruit cuticles. Both cuticular membranes (CM) and dewaxed CM (DCM) sorbed more NAA at pH 2.2 than at pH 6.2. At each pH, increasing temperature (15° to 35°C) decreased NAA sorption by both CM and DCM. The same qualitative temperature (5° to 25°) response was observed with 2,4-D for CM at low (0.8) pH. Chemical names used: 2-(1-naphthyl)acetic acid (NAA); (2,4-dichlorophenoxy)acetic acid (2,4-D).
L'invention concerne des compositions comprenant de l'acide abscisique, et/ou des sels, d... more L'invention concerne des compositions comprenant de l'acide abscisique, et/ou des sels, des derives et des analogues de ceux-ci, ainsi que des procedes pharmaceutiques et/ou nutraceutiques associes.
A process of inhibiting stem elongation in flowering bulbous plants comprising treating said bulb... more A process of inhibiting stem elongation in flowering bulbous plants comprising treating said bulbous plants with an effective amount of an ACC synthase inhibitor to inhibit stem elongation.
Aminoethoxyvinylglycine (AVG) is a naturally occurring plant growth regulator that was first pate... more Aminoethoxyvinylglycine (AVG) is a naturally occurring plant growth regulator that was first patented in 1973 (US patent #3,751,459). AVG has been shown to competitively inhibit ACC (1-aminocyclopropane-1-carboxylic acid) synthase (Yu et al., 1979, Arch. Biochem. Biophys. 198:280–286), which is the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. Because of this unique mode of action, AVG has been tested over the years on a wide array of plant tissues. Studies on plants of horticultural interest have included cut flowers (e.g., Baker et al., 1977 HortScience 12:38–39), greenhouse crops (e.g., Saltveit and Larson, 1981, J. Amer. Soc. Hort. Sci. 106:156–159), and tree fruits (e.g., Bangerth, 1978, J. Amer. Soc. Hort. Sci. 103:401–403). AVG is currently being developed by Abbott Laboratories for use on apples (e.g., Shafer et al., 1995, Proc. 22nd Annu. PGRSA Mtg, pg 11–15). This presentation: a) briefly reviews ...
ReTain™ is an organic, water-soluble formulation that contains 15% (w/w) of aminoethoxy-vinylglyc... more ReTain™ is an organic, water-soluble formulation that contains 15% (w/w) of aminoethoxy-vinylglycine (AVG). AVG, a naturally occurring plant growth regulator, competitively inhibits ACC (1-aminocyclopropane-1-carboxylic acid) synthase, the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. ReTain has been under commercial development for the past 6 years, which includes U.S. EPA-approved Experimental Use Permit (EUP) programs in 1995 (Shafer et al., 1996, Proc 23rd Annu. PGRSA Mtg., p. 233–234) and 1996. Under the 1996 EUP, ReTain was tested on nearly 4000 acres of apples in 18 states. When used according to label directions (i.e., 50 g AVG/acre applied 4 weeks before anticipated harvest) with a nonionic surfactant, ReTain effectively reduced preharvest drop and generally resulted in fruit of higher quality than untreated (control) or naphthaleneacetic acid (NAA) -treated fruit. ReTain can delay fruit maturity (...
Interaction of fertilizer use, cultivar and/or soil temperature with development of cranberry (Va... more Interaction of fertilizer use, cultivar and/or soil temperature with development of cranberry (Vaccinium macrocarpon Ait) fruit size and mass has been studied. Underfertilization impacts on fruit size after an initial lag of at least one season. The shape of fruit growth curves were similar for 6 cultivars: varying in growth rate for small vs large fruited cultivars. Frequencies for size classes (5.6-8 mm, 8-11.2 mm, 11.2-13.2 mm, 13.2-16 mm, > 16mm) shifted predictably during fruit development. The timing for the shifts may be related to soil temperature (3 year comparison) at critical stages. This information may have implications for forecasting fruit size and estimating crops in commercial production.
Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
Journal of the American Society for Horticultural Science, 1994
14C-urea penetration of isolated tomato (Lycopersicon esculentum Mill. cv. `Pik Red') fruit c... more 14C-urea penetration of isolated tomato (Lycopersicon esculentum Mill. cv. `Pik Red') fruit cuticular membranes (CM) was studied as a function of concentration and temperature. There was no significant effect of cuticular wax on urea penetration at 25C, permeances for the CM being 8.4 × 10-10 and dewaxed CM (DCM) 11.1 × 10-10·m·s-1. Time lags were near zero for both CM and DCM. Steady-state diffusion analysis suggests that the relatively low cuticular permeance of urea is due to low partitioning that offsets high diffusivity. Urea flux through the CM and DCM showed ≈1.5- and 1.9-fold increases, respectively, for each 10C increase between 5 and 45C. Urea flux across CM and DCM increased linearly with concentration (10 μm to 1 m) and, thus, was a first-order process.
Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomat... more The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomato (Lycopersicon esculentum Mill. cv. Sprinter) fruit cuti cles. Both cuticular membranes (CM) and dewaxed CM (DCM) sorbed more NAA at pH 2.2 than at pH 6.2. A t each pH, increasing temperature (15° to 35°C) decreased NAA sorption by both CM and DCM. The same qualitative temperature (5° to 25°) response was observed with 2,4-D for CM at low (0.8) pH. Chemical names used: 2-(l-naphthyl)acetic acid (NAA); (2,4-dichlorophenoxy)acetic acid (2,4-D). H o r t S c i e n c e 23(l):204-206. 1988. Foliar absorption of an applied substance is a multistep process governed by both physical and biological factors. Environ mental and/or solution characteristics (e.g., temperature, pH) at the time of application can have a profound effect on this complex process (7, 8 , 18). Typically, for weak or ganic acid auxins, absorption increases with increasing temperature and/or decreasing pH. The plant cuticle is the initial and primary barrier to foliar absorption (2, 5). Transfer across the cuticle occurs by sorption into the cuticular membrane, diffusion through and desorption from the cuticle on the cell wall side. Therefore, in an effort to further elu cidate the effects of temperature and pH on absorption, we used isolated tomato fruit cu ticles as a model cuticle and NAA and 2,4-D as model weak organic acid auxins. To mato fruit cuticle was selected because con siderable inform ation is available on its composition, structure, and permeability characteristics . NAA and 2,4-D were selected because they are im portant agrochemical representatives of the weak organic acid auxins. In these studies we focused on sorption because it represents an important early process in cuticular pen-
Asparagus (A sp a r a g u s o ffic in a lis L.) root tissue added to soil at 2, 4, or 6 g (dry we... more Asparagus (A sp a r a g u s o ffic in a lis L.) root tissue added to soil at 2, 4, or 6 g (dry weight basis) per 100 g of dry soil generally inhibited lettuce and delayed tomato and asparagus seedling emergence when incorporated in soil for 0 or 28 days before seeding. The toxicity of the 2 and 4 g rates of asparagus root tissue was diminished after 50 days, but the 6 g rate inhibited and/or delayed emergence 50 and 90 days after incorporation in soil. These results suggest that asparagus root tissues contain a heteroand auto-toxic allelopathic compound(s) that is inactivated with increasing time in the soil. In recent years many asparagus plantings in New Jersey have experienced a decrease in plant vigor, and this has previously been attributed to a Fusarium root, stem, and crown rot complex (2, 3). Some evidence now sug gests that allelopathy, the process whereby a chemical compound (phytotoxin) is re leased into the soil environment by 1 plant and inhibits the growth of a neighboring plant (6 , 7), also may be involved in asparagus decline. The presence of an allelopathic sub stance^) in asparagus roots grown under both field (1, 4, 10) and aseptic (10) conditions recently has been confirmed. No information was obtained from these studies on the effect of increasing amounts of tissue in the soil, nor on the persistence of the toxic effect in the soil. The following experiments therefore were designed to ex amine the effect of increasing amounts of asparagus root tissue present in a soil envi ronment and the duration of that toxicity un der defined conditions. Asparagus plants were raised in a nursery in Salem County, New Jersey, on a soil with no history of asparagus planting or herbicide usage. Five-month old plants were harvested at the end of the growing season, and only
The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomat... more The effects of pH and temperature were determined on NAA sorption by enzymatically isolated tomato (Lycopersicon esculentum Mill. cv. Sprinter) fruit cuticles. Both cuticular membranes (CM) and dewaxed CM (DCM) sorbed more NAA at pH 2.2 than at pH 6.2. At each pH, increasing temperature (15° to 35°C) decreased NAA sorption by both CM and DCM. The same qualitative temperature (5° to 25°) response was observed with 2,4-D for CM at low (0.8) pH. Chemical names used: 2-(1-naphthyl)acetic acid (NAA); (2,4-dichlorophenoxy)acetic acid (2,4-D).
L'invention concerne des compositions comprenant de l'acide abscisique, et/ou des sels, d... more L'invention concerne des compositions comprenant de l'acide abscisique, et/ou des sels, des derives et des analogues de ceux-ci, ainsi que des procedes pharmaceutiques et/ou nutraceutiques associes.
A process of inhibiting stem elongation in flowering bulbous plants comprising treating said bulb... more A process of inhibiting stem elongation in flowering bulbous plants comprising treating said bulbous plants with an effective amount of an ACC synthase inhibitor to inhibit stem elongation.
Aminoethoxyvinylglycine (AVG) is a naturally occurring plant growth regulator that was first pate... more Aminoethoxyvinylglycine (AVG) is a naturally occurring plant growth regulator that was first patented in 1973 (US patent #3,751,459). AVG has been shown to competitively inhibit ACC (1-aminocyclopropane-1-carboxylic acid) synthase (Yu et al., 1979, Arch. Biochem. Biophys. 198:280–286), which is the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. Because of this unique mode of action, AVG has been tested over the years on a wide array of plant tissues. Studies on plants of horticultural interest have included cut flowers (e.g., Baker et al., 1977 HortScience 12:38–39), greenhouse crops (e.g., Saltveit and Larson, 1981, J. Amer. Soc. Hort. Sci. 106:156–159), and tree fruits (e.g., Bangerth, 1978, J. Amer. Soc. Hort. Sci. 103:401–403). AVG is currently being developed by Abbott Laboratories for use on apples (e.g., Shafer et al., 1995, Proc. 22nd Annu. PGRSA Mtg, pg 11–15). This presentation: a) briefly reviews ...
ReTain™ is an organic, water-soluble formulation that contains 15% (w/w) of aminoethoxy-vinylglyc... more ReTain™ is an organic, water-soluble formulation that contains 15% (w/w) of aminoethoxy-vinylglycine (AVG). AVG, a naturally occurring plant growth regulator, competitively inhibits ACC (1-aminocyclopropane-1-carboxylic acid) synthase, the enzyme responsible for the conversion of S-adenosylmethionine (SAM) to ACC, the immediate precursor of ethylene in plants. ReTain has been under commercial development for the past 6 years, which includes U.S. EPA-approved Experimental Use Permit (EUP) programs in 1995 (Shafer et al., 1996, Proc 23rd Annu. PGRSA Mtg., p. 233–234) and 1996. Under the 1996 EUP, ReTain was tested on nearly 4000 acres of apples in 18 states. When used according to label directions (i.e., 50 g AVG/acre applied 4 weeks before anticipated harvest) with a nonionic surfactant, ReTain effectively reduced preharvest drop and generally resulted in fruit of higher quality than untreated (control) or naphthaleneacetic acid (NAA) -treated fruit. ReTain can delay fruit maturity (...
Interaction of fertilizer use, cultivar and/or soil temperature with development of cranberry (Va... more Interaction of fertilizer use, cultivar and/or soil temperature with development of cranberry (Vaccinium macrocarpon Ait) fruit size and mass has been studied. Underfertilization impacts on fruit size after an initial lag of at least one season. The shape of fruit growth curves were similar for 6 cultivars: varying in growth rate for small vs large fruited cultivars. Frequencies for size classes (5.6-8 mm, 8-11.2 mm, 11.2-13.2 mm, 13.2-16 mm, > 16mm) shifted predictably during fruit development. The timing for the shifts may be related to soil temperature (3 year comparison) at critical stages. This information may have implications for forecasting fruit size and estimating crops in commercial production.
Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-b... more Partition and sorption characteristics of the cytokinin N-(phenylmethyl)-lH-purine-6-amine (N''-benzyladenine, BA) in two model systems were studied at 25°C. Apparent partition coefficients (K?") for BA in an «-octanol:water (buffer) system were independent of BA concentration but decreased with increasing buffer concentration (ionie strength). A plot of K^" values versus pH (2 to 12) was a bell-shaped curve. At pH 2 or 12, K^" values were low (less than 2). As pH approached neutrality, K^" values increased approximately 20-fold. Estimates of pK,(3.3) and pK, (10.7) values for BA were obtained from these data. The accuracy of this approach to determining pK values was verified with 2-(l-naphthyl)acetic acid (NAA). Correction of K''" values for dissociation effects on BA yielded partition coefficients (K) whose overall mean was 37. Sorption of BA by cuticles enzymatically isolated from abaxial and adaxial surfaces of mature rubber plant {Ficus elastica Roxb. cv. decora) leaves was initially rapid, however equilibrium was not reached by 432 h. At pH 2, sorption was low (approximately 5 fxmol kg"'), whereas at pH 6 sorption increased approximately 11-fold. Sorption by abaxial cuticular membranes (CM) and dewaxed CM (DCM) was slightly higher than corresponding adaxial CM and DCM. Using natural logarithm values, RP" data were linearly-correlated with CM (r = 0.98) and DCM (r = 0.99) sorption data.
Journal of the American Society for Horticultural Science, 1994
14C-urea penetration of isolated tomato (Lycopersicon esculentum Mill. cv. `Pik Red') fruit c... more 14C-urea penetration of isolated tomato (Lycopersicon esculentum Mill. cv. `Pik Red') fruit cuticular membranes (CM) was studied as a function of concentration and temperature. There was no significant effect of cuticular wax on urea penetration at 25C, permeances for the CM being 8.4 × 10-10 and dewaxed CM (DCM) 11.1 × 10-10·m·s-1. Time lags were near zero for both CM and DCM. Steady-state diffusion analysis suggests that the relatively low cuticular permeance of urea is due to low partitioning that offsets high diffusivity. Urea flux through the CM and DCM showed ≈1.5- and 1.9-fold increases, respectively, for each 10C increase between 5 and 45C. Urea flux across CM and DCM increased linearly with concentration (10 μm to 1 m) and, thus, was a first-order process.
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Papers by Warren Shafer