Leaves of Eucalyptus nitens (Deane & Maiden) Maidenwere sampled during establishment of seedlings that were deprived of nutrientsor fertilised at planting. Extracts were analysed for polyphenolic compoundsusing high pressure liquid chromatography (HPLC) in conjunction with UV diodearray and electrospray ionisation mass spectrometry (ESI-MS) with negative iondetection as well as direct MS injection. The presence of quercetin, rutin,sideroxylonal A and B andpenta-galloylglucose were confirmed by comparison with standards. Othergalloylglucoses were identified by first principles. Galloylglucoses comprisedabout 75% of polyphenolics. Quercetin and various quercetin glycosidescomprised ca 85% of flavonols. The anthocyanins,cyanidin-3-glycoside and cyanidin-3,5-diglycoside were identified from directinjection MS data. HPLC–ESI-MS was found to be a superior analyticaltechnique compared to conventional HPLC–UV diode array detection due toco-elution of peaks under UV. Temporal variation of anthocyanins may berelated to the severity of cold-induced photoinhibition. Changes ingalloylglucoses and flavonols were similar with time and related to levels offoliar nitrogen. The suitability of HPLC–ESI-MS for the study of foliarpolyphenolics, the phenolic constitution of E. nitensfoliage, and temporal variation of the phenolic constituents during a seedlingestablishment period of 29 weeks are demonstrated.
在种植时剥夺营养或施肥的幼苗建立期间，对nitens桉树(Deane & Maiden)的叶子进行取样。采用高压液相色谱(HPLC)、紫外二极管阵列、电喷雾电离质谱(ESI-MS)、负离子检测和直接质谱注射对提取物中的多酚类化合物进行分析。通过与标准品的比较，确定了槲皮素、芦丁、sideroxylonal A、B和penta- gallylglucose的存在。用第一性原理鉴定了其他没食子基葡萄糖。约75%的多酚类物质是由没食子糖构成的。槲皮素和各种槲皮素糖苷约占黄酮醇的85%。直接进样质谱分析鉴定了花青素、花青素-3-糖苷和花青素-3,5-二糖苷。与传统的高效液相色谱-紫外二极管阵列检测相比，高效液相色谱- esi - ms是一种优越的分析技术，因为它在紫外下共同洗脱了峰。花青素的时间变化可能与冷诱导光抑制的严重程度有关。葡萄糖和黄酮醇含量随时间变化相似，且与叶面氮含量有关。验证了HPLC-ESI-MS技术在29周的育苗过程中对叶面多酚类物质、叶面酚类物质组成以及叶面酚类物质时间变化的适用性。
{"title":"Temporal variation of tannins (galloylglucoses), flavonols and anthocyanins in leaves of Eucalyptus nitens seedlings : implications for light attenuation and antioxidant activities","authors":"D. Close, N. Davies, C. Beadle","doi":"10.1071/PP00112","DOIUrl":"https://doi.org/10.1071/PP00112","url":null,"abstract":"Leaves of Eucalyptus nitens (Deane & Maiden) Maidenwere sampled during establishment of seedlings that were deprived of nutrientsor fertilised at planting. Extracts were analysed for polyphenolic compoundsusing high pressure liquid chromatography (HPLC) in conjunction with UV diodearray and electrospray ionisation mass spectrometry (ESI-MS) with negative iondetection as well as direct MS injection. The presence of quercetin, rutin,sideroxylonal A and B andpenta-galloylglucose were confirmed by comparison with standards. Othergalloylglucoses were identified by first principles. Galloylglucoses comprisedabout 75% of polyphenolics. Quercetin and various quercetin glycosidescomprised ca 85% of flavonols. The anthocyanins,cyanidin-3-glycoside and cyanidin-3,5-diglycoside were identified from directinjection MS data. HPLC–ESI-MS was found to be a superior analyticaltechnique compared to conventional HPLC–UV diode array detection due toco-elution of peaks under UV. Temporal variation of anthocyanins may berelated to the severity of cold-induced photoinhibition. Changes ingalloylglucoses and flavonols were similar with time and related to levels offoliar nitrogen. The suitability of HPLC–ESI-MS for the study of foliarpolyphenolics, the phenolic constitution of E. nitensfoliage, and temporal variation of the phenolic constituents during a seedlingestablishment period of 29 weeks are demonstrated.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82302566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C4 grasses are grouped into three biochemical subtypes,NAD malic enzyme (NAD–ME), NADP malic enzyme (NADP–ME)and phosphoenolpyruvate carboxykinase (PCK), possessingcharacteristic leaf anatomy, biochemistry and physiology. This studyinvestigates the physiological implications of these differences by comparing growth, water use efficiency (WUE, dry matter gain per unit water transpired) and gas exchange characteristics of NAD–MEand NADP–ME C4 grasses belonging to threetaxonomic groups (main Chloroid assemblage, Paniceae and Andropogoneae). Wegrew 28 C4 grasses from seeds for 6 weeks in aglasshouse under ample water and nutrients in winter and summer. Theinter-specific variation in plant dry mass (30-fold) was much greater thanthat in WUE (2-fold). There was no significantdifference in average WUE between NAD–ME andNADP–ME grasses. Average plant dry mass andWUE were highest in the Paniceae (mostlyNADP–ME), lowest in the Andropogoneae (NADP–ME) and intermediate in the Chloroid (NAD–ME). CO2assimilation rate (A), stomatal conductance(g) and the ratio of intercellular to ambient CO2 partial pressure (pi/p a )were measured under standard conditions at high light. AverageA and g were slightly higher inNADP–ME than NAD–ME grasses, but pi/p awas similar for the two subtypes. A did not differbetween winter and summer experiments in spite of a 3-fold difference inmaximal daily irradiance. Dry matter accumulation correlated positively withleaf area ratio (LAR; plant leaf area per unit plant drymass) and specific leaf area (SLA; leaf area per unitleaf dry mass) in NAD–ME, but not NADP–ME, grasses.Variation in A (expressed on a per area basis) did notcorrelate with biomass accumulation or SLA. Whenexpressed on a dry mass basis, A correlated withSLA in all C4 grasses. This studyshows that there is large inter-specific variation in growth among the C4 grasses, but average WUE andA/g are similar forNAD–ME and NADP–ME species under well-wateredconditions.
{"title":"Carbon and water economy of Australian NAD-ME and NADP-ME C4 grasses","authors":"O. Ghannoum, S. Caemmerer, J. Conroy","doi":"10.1071/PP00078","DOIUrl":"https://doi.org/10.1071/PP00078","url":null,"abstract":"C4 grasses are grouped into three biochemical subtypes,NAD malic enzyme (NAD–ME), NADP malic enzyme (NADP–ME)and phosphoenolpyruvate carboxykinase (PCK), possessingcharacteristic leaf anatomy, biochemistry and physiology. This studyinvestigates the physiological implications of these differences by comparing growth, water use efficiency (WUE, dry matter gain per unit water transpired) and gas exchange characteristics of NAD–MEand NADP–ME C4 grasses belonging to threetaxonomic groups (main Chloroid assemblage, Paniceae and Andropogoneae). Wegrew 28 C4 grasses from seeds for 6 weeks in aglasshouse under ample water and nutrients in winter and summer. Theinter-specific variation in plant dry mass (30-fold) was much greater thanthat in WUE (2-fold). There was no significantdifference in average WUE between NAD–ME andNADP–ME grasses. Average plant dry mass andWUE were highest in the Paniceae (mostlyNADP–ME), lowest in the Andropogoneae (NADP–ME) and intermediate in the Chloroid (NAD–ME). CO2assimilation rate (A), stomatal conductance(g) and the ratio of intercellular to ambient CO2 partial pressure (pi/p a )were measured under standard conditions at high light. AverageA and g were slightly higher inNADP–ME than NAD–ME grasses, but pi/p awas similar for the two subtypes. A did not differbetween winter and summer experiments in spite of a 3-fold difference inmaximal daily irradiance. Dry matter accumulation correlated positively withleaf area ratio (LAR; plant leaf area per unit plant drymass) and specific leaf area (SLA; leaf area per unitleaf dry mass) in NAD–ME, but not NADP–ME, grasses.Variation in A (expressed on a per area basis) did notcorrelate with biomass accumulation or SLA. Whenexpressed on a dry mass basis, A correlated withSLA in all C4 grasses. This studyshows that there is large inter-specific variation in growth among the C4 grasses, but average WUE andA/g are similar forNAD–ME and NADP–ME species under well-wateredconditions.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83611024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Membrane transport activity associated with growth and nutritional status of a marine microheterotroph Thraustochytrium sp. was studied using non-invasive ion-selective slowly vibrating microelectrodes (the MIFE technique). Net fluxes of H + , Ca 2+ and Na + underwent regular changes as the cell progressed from the zoospore to sporangium stages of development. The most pronounced change was a decrease in the net H + influx, which we suggest could be associated with the changes in cytoskeletal organization required for cell cleavage and zoospore release. As cell development progressed from the zoospore stage towards maturity, non-damping endogenous ultradian oscillations (period range of several minutes) became evident. At the sporangium stage, as many as 85% of cells possessed oscillatory membrane transport activity. It is suggested that ultradian ion flux oscillations in Thraustochytrium sp. may be causally linked with cell developmental processes. Discrete Fourier transform and cross-correlation analysis revealed a close association between oscillatory patterns of H + and Na + fluxes. The possibility that these oscillations result from the rhythmical activity of a Na + /H + co-transporter located at the plasma membrane of Thraustochytrium sp. is considered. Oscillations in net Ca 2+ flux were apparently not linked to those in H+ and Na + , and are believed to be due to some other physiological processes. Periods of net H + and Na + flux oscillations were strongly dependent on the external Na + concentrations in the bathing medium. As sodium is considered to be an essential element in Thraustochytrium sp., it is suggested that the functional role of such ultradian oscillations may be their involvement in the frequency-encoding mechanism that provides developing cells with information about environment, and nutritional status in particular.
{"title":"Membrane transport activity and ultradian ion flux oscillations associated with cell cycle of Thraustochytrium sp","authors":"L. Shabala, S. Shabala, T. Ross, T. McMeekin","doi":"10.1071/PP00121","DOIUrl":"https://doi.org/10.1071/PP00121","url":null,"abstract":"Membrane transport activity associated with growth and nutritional status of a marine microheterotroph Thraustochytrium sp. was studied using non-invasive ion-selective slowly vibrating microelectrodes (the MIFE technique). Net fluxes of H + , Ca 2+ and Na + underwent regular changes as the cell progressed from the zoospore to sporangium stages of development. The most pronounced change was a decrease in the net H + influx, which we suggest could be associated with the changes in cytoskeletal organization required for cell cleavage and zoospore release. As cell development progressed from the zoospore stage towards maturity, non-damping endogenous ultradian oscillations (period range of several minutes) became evident. At the sporangium stage, as many as 85% of cells possessed oscillatory membrane transport activity. It is suggested that ultradian ion flux oscillations in Thraustochytrium sp. may be causally linked with cell developmental processes. Discrete Fourier transform and cross-correlation analysis revealed a close association between oscillatory patterns of H + and Na + fluxes. The possibility that these oscillations result from the rhythmical activity of a Na + /H + co-transporter located at the plasma membrane of Thraustochytrium sp. is considered. Oscillations in net Ca 2+ flux were apparently not linked to those in H+ and Na + , and are believed to be due to some other physiological processes. Periods of net H + and Na + flux oscillations were strongly dependent on the external Na + concentrations in the bathing medium. As sodium is considered to be an essential element in Thraustochytrium sp., it is suggested that the functional role of such ultradian oscillations may be their involvement in the frequency-encoding mechanism that provides developing cells with information about environment, and nutritional status in particular.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89684282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Expansion and dry weight (DW) of wheat leaves are spatially distributed along the axis and affected by salinity. The objective of this study was to evaluate the effect of salinity on the spatial distribution of cellular cross-sectional area and DW in the elongating and mature leaf zones of leaf 4 of the main stem of spring wheat (Triticum aestivum L. cv. Lona) during its linear growth phase. Plants were grown in illitic–chloritic silt loam with 0 and 120 mM NaCl in a growth chamber. Cellular cross-sectional area and DW contents of leaves were determined on the 5–20-mm scale along the leaf axis. Spatial distribution of cellular cross-sectional area changed slightly with distance within the elongation zone in both treatments. The cellular cross-sectional area of the leaf at 120 mM NaCl was reduced by 32% at 5 mm, as compared with about 36% averaged from the region between 5 and 30 mm from the leaf base, indicating that the reduction in the cellular cross-sectional area by salinity occurred mainly at the leaf base when the leaf initiates. A slight decrease in the DW per leaf length at a given location in the elongation zone may be due to the strongly decreased cellular cross-sectional area by salinity. This suggests that the limitation of leaf growth by salinity may be due mainly to the effect of salinity on leaf expansion, but not due to the effect on the synthesis of dry matter.
小麦叶片膨胀和干重在空间上沿轴向分布，并受盐度影响。以春小麦(Triticum aestivum L. cv)主茎第4叶伸长区和成熟叶区为研究对象，研究了盐度对细胞横截面积和DW空间分布的影响。Lona)在其线性生长阶段。在生长室中，用0和120 mM NaCl在绿泥质粉砂壤土中培养植株。沿叶轴在5 ~ 20 mm尺度上测定叶片的细胞截面积和DW含量。在两个处理中，细胞横截面积的空间分布随伸长区的距离变化不大。在120 mM NaCl处理下，叶片的细胞横截面积在5 mM处减少了32%，而在距叶基5 ~ 30 mM处平均减少了约36%，说明盐度对细胞横截面积的减少主要发生在叶片萌发时的叶基处。在伸长区某一特定位置每叶长DW的轻微下降可能是由于盐度使细胞横截面积大大减少所致。这表明盐度对叶片生长的限制可能主要是由于盐度对叶片膨胀的影响，而不是由于对干物质合成的影响。
{"title":"Reduced cellular cross-sectional area in the leaf elongation zone of wheat causes a decrease in dry weight deposition under saline conditions","authors":"Yuncai Hu, U. Schmidhalter","doi":"10.1071/PP00073","DOIUrl":"https://doi.org/10.1071/PP00073","url":null,"abstract":"Expansion and dry weight (DW) of wheat leaves are spatially distributed along the axis and affected by salinity. The objective of this study was to evaluate the effect of salinity on the spatial distribution of cellular cross-sectional area and DW in the elongating and mature leaf zones of leaf 4 of the main stem of spring wheat (Triticum aestivum L. cv. Lona) during its linear growth phase. Plants were grown in illitic–chloritic silt loam with 0 and 120 mM NaCl in a growth chamber. Cellular cross-sectional area and DW contents of leaves were determined on the 5–20-mm scale along the leaf axis. Spatial distribution of cellular cross-sectional area changed slightly with distance within the elongation zone in both treatments. The cellular cross-sectional area of the leaf at 120 mM NaCl was reduced by 32% at 5 mm, as compared with about 36% averaged from the region between 5 and 30 mm from the leaf base, indicating that the reduction in the cellular cross-sectional area by salinity occurred mainly at the leaf base when the leaf initiates. A slight decrease in the DW per leaf length at a given location in the elongation zone may be due to the strongly decreased cellular cross-sectional area by salinity. This suggests that the limitation of leaf growth by salinity may be due mainly to the effect of salinity on leaf expansion, but not due to the effect on the synthesis of dry matter.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81660246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The potential use of C4 biochemical subtypes [nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME), nicotinamide adenine dinucleotide-malic enzyme (NAD-ME) and phosphoenolpyruvate carboxykinase (PCK)] as delimiters of plant functional types (PFTs) with distinct responses to rising atmospheric CO2 concentrations was investigated in South African grass species. Gas exchange and above-ground growth in ambient and elevated CO2 (360 and 660 µmol mol–1 , respectively) were determined in three NADP-ME species, two NAD-ME species, two PCK species and one C3 species, all excavated from the same field site. Plants were grown in open-top chambers in a greenhouse for 178 d. Net CO2 assimilation rates were only significantly increased in one NAD-ME species, but stomatal conductances decreased (in six out of eight species, by a mean of 46%) and instantaneous leaf water-use efficiency increased (in all species, by a mean of 89%) in elevated CO2. These responses did not differ between photosynthetic pathways. Parameters derived from photosynthetic CO2 and light response curves were also not differentially influenced by CO2 treatment between pathways. Gas exchange responses were generally poorly related to CO2 responsiveness. Significant increases in leaf growth and canopy leaf area in elevated CO2 were found in two NADP-ME species, whereas increases in non-leaf above-ground growth were measured in three species representing all three C4 subtypes. Growth responses in elevated CO2 were apparently not simply correlated with biochemical subtype characteristics, although the most significant responses (particularly at the leaf level) were found for the NADP-ME pathway. This result was more likely attributable to the significant positive correlation found between CO2 responsiveness of leaf growth and relative leaf regrowth potential of individual species, the latter being higher in the two responsive NADP-ME species. Therefore, categorisation of PFTs according to relative growth potential may be more appropriate for predictions of CO2 responsiveness in C4 grasses.
{"title":"Growth responses to elevated CO2 in NADP-ME, NAD-ME and PCK C4 grasses and a C3 grass from South Africa.","authors":"S. Wand, G. Midgley, W. Stock","doi":"10.1071/PP99104","DOIUrl":"https://doi.org/10.1071/PP99104","url":null,"abstract":"The potential use of C4 biochemical subtypes [nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME), nicotinamide adenine dinucleotide-malic enzyme (NAD-ME) and phosphoenolpyruvate carboxykinase (PCK)] as delimiters of plant functional types (PFTs) with distinct responses to rising atmospheric CO2 concentrations was investigated in South African grass species. Gas exchange and above-ground growth in ambient and elevated CO2 (360 and 660 µmol mol–1 , respectively) were determined in three NADP-ME species, two NAD-ME species, two PCK species and one C3 species, all excavated from the same field site. Plants were grown in open-top chambers in a greenhouse for 178 d. Net CO2 assimilation rates were only significantly increased in one NAD-ME species, but stomatal conductances decreased (in six out of eight species, by a mean of 46%) and instantaneous leaf water-use efficiency increased (in all species, by a mean of 89%) in elevated CO2. These responses did not differ between photosynthetic pathways. Parameters derived from photosynthetic CO2 and light response curves were also not differentially influenced by CO2 treatment between pathways. Gas exchange responses were generally poorly related to CO2 responsiveness. Significant increases in leaf growth and canopy leaf area in elevated CO2 were found in two NADP-ME species, whereas increases in non-leaf above-ground growth were measured in three species representing all three C4 subtypes. Growth responses in elevated CO2 were apparently not simply correlated with biochemical subtype characteristics, although the most significant responses (particularly at the leaf level) were found for the NADP-ME pathway. This result was more likely attributable to the significant positive correlation found between CO2 responsiveness of leaf growth and relative leaf regrowth potential of individual species, the latter being higher in the two responsive NADP-ME species. Therefore, categorisation of PFTs according to relative growth potential may be more appropriate for predictions of CO2 responsiveness in C4 grasses.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83766140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Noguchi, Chun-Sim U. Go, Shin-Ichi Miyazawa, I. Terashima, S. Ueda, T. Yoshinari
In mature leaves, adenosine triphosphate (ATP) provided by respiration is used for maintenance of leaves and carbohydrate export (starch mobilisation and phloem loading). The main maintenance processes of mature leaves include turnover of existing structures (e.g. proteins and membranes) and the trans-membrane transport of solutes. In order to mechanistically estimate these costs in mature leaves and compare them between sun and shade species, we measured the costs of protein turnover and carbohydrate export in mature leaves of Alocasia odora (Lodd.) Spach., a shade-tolerant species, and Phaseolus vulgaris L., a sun species, in the night. We estimated the rate of ATP production from the rate of O 2 uptake, taking account of the contribution of the alternative respiratory pathway, assessed by the O 2 isotope fractionation technique. The energy consumption of protein turnover was estimated from the decrease in the rate of ATP production in the presence of an inhibitor of cytosolic protein synthesis. Examination of the anatomy of the minor veins in the leaves revealed that A. odora employs symplastic phloem loading, while P. vulgaris was reported to employ apoplastic loading. Based on these phloem loading types and the difference between the rate of carbohydrate decrease and the CO 2 efflux rate in the leaves, we calculated the ATP cost for carbohydrate export. The costs estimated for two processes amounted to about 40% of the ATP production rate in A. odora and 80% in P. vulgaris. The absolute costs for the two processes in the leaves of A. odora were much lower than those of P. vulgaris. Both the cost of protein turnover per unit leaf nitrogen and that of carbohydrate export per exported carbon were lower in the leaves of A. odora. Low ATP consumption rates by these cellular processes would explain the low respiratory rate in A. odora.
{"title":"Costs of protein turnover and carbohydrate export in leaves of sun and shade species","authors":"K. Noguchi, Chun-Sim U. Go, Shin-Ichi Miyazawa, I. Terashima, S. Ueda, T. Yoshinari","doi":"10.1071/PP00057","DOIUrl":"https://doi.org/10.1071/PP00057","url":null,"abstract":"In mature leaves, adenosine triphosphate (ATP) provided by respiration is used for maintenance of leaves and carbohydrate export (starch mobilisation and phloem loading). The main maintenance processes of mature leaves include turnover of existing structures (e.g. proteins and membranes) and the trans-membrane transport of solutes. In order to mechanistically estimate these costs in mature leaves and compare them between sun and shade species, we measured the costs of protein turnover and carbohydrate export in mature leaves of Alocasia odora (Lodd.) Spach., a shade-tolerant species, and Phaseolus vulgaris L., a sun species, in the night. We estimated the rate of ATP production from the rate of O 2 uptake, taking account of the contribution of the alternative respiratory pathway, assessed by the O 2 isotope fractionation technique. The energy consumption of protein turnover was estimated from the decrease in the rate of ATP production in the presence of an inhibitor of cytosolic protein synthesis. Examination of the anatomy of the minor veins in the leaves revealed that A. odora employs symplastic phloem loading, while P. vulgaris was reported to employ apoplastic loading. Based on these phloem loading types and the difference between the rate of carbohydrate decrease and the CO 2 efflux rate in the leaves, we calculated the ATP cost for carbohydrate export. The costs estimated for two processes amounted to about 40% of the ATP production rate in A. odora and 80% in P. vulgaris. The absolute costs for the two processes in the leaves of A. odora were much lower than those of P. vulgaris. Both the cost of protein turnover per unit leaf nitrogen and that of carbohydrate export per exported carbon were lower in the leaves of A. odora. Low ATP consumption rates by these cellular processes would explain the low respiratory rate in A. odora.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80922963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Picciarelli, N. Ceccarelli, F. Paolicchi, Gianni Calistri
The occurrence and the dynamics of free and bound indole-3-acetic acid (IAA) in different parts of Phaseolus coccineus L. seeds were investigated at various developmental stages. Results show that free and bound IAA content in the single seed parts is quite different, and changes with different patterns during seed growth. The highest concentration of total IAA was found in early-heart stage embryos, while the total IAA concentration in the suspensor at early-heart stage is much lower than in the embryos, and remains almost constant in the later stages. Integuments have an intermediate content at the first two developmental stages, while showing the highest concentration of total IAA at the cotyledonary stage. Concerning the percentage of free IAA in relation to the total pool, we found that in the embryos free IAA accounts for 26-28% in the first two stages then increases up to 44% at the cotyledonary stage. In suspensors, the percentage of free IAA is much higher (90%) in all developmental stages. We discuss the idea that the different level of auxin between embryos and the suspensor might play an important role in the establishment of embryo polarity.
{"title":"Endogenous auxins and embryogenesis in Phaseolus coccineus","authors":"P. Picciarelli, N. Ceccarelli, F. Paolicchi, Gianni Calistri","doi":"10.1071/PP00086","DOIUrl":"https://doi.org/10.1071/PP00086","url":null,"abstract":"The occurrence and the dynamics of free and bound indole-3-acetic acid (IAA) in different parts of Phaseolus coccineus L. seeds were investigated at various developmental stages. Results show that free and bound IAA content in the single seed parts is quite different, and changes with different patterns during seed growth. The highest concentration of total IAA was found in early-heart stage embryos, while the total IAA concentration in the suspensor at early-heart stage is much lower than in the embryos, and remains almost constant in the later stages. Integuments have an intermediate content at the first two developmental stages, while showing the highest concentration of total IAA at the cotyledonary stage. Concerning the percentage of free IAA in relation to the total pool, we found that in the embryos free IAA accounts for 26-28% in the first two stages then increases up to 44% at the cotyledonary stage. In suspensors, the percentage of free IAA is much higher (90%) in all developmental stages. We discuss the idea that the different level of auxin between embryos and the suspensor might play an important role in the establishment of embryo polarity.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74084398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The lignifying xylem from Zinnia elegans hypocotyls gives an intense reaction with the MAule reagent, which is specific for syringyl moieties. The presence of syringyl moieties in the β-O-4 lignin fraction from Z. elegans cell walls was confirmed by thioacidolysis, which gave, as main products, the thioethylated monomers arising from aryl-glycerol-β-aryl ether structures derived from coniferyl and sinapyl alcohols. The guaiacyl/syringyl molar ratio for this lignin fraction was 43/57. Besides β-O-4 syringyl lignins, lignifying Z. elegans hypocotyls also contain a basic peroxidase capable of oxidizing syringyl moieties, such as those present in sinapyl alcohol and syringaldazine, the latter a chromogenic substrate containing the syringyl group specific for angiosperm lignins. Competitive inhibitor-dissected histochemistry of the developing xylem revealed that the stain for syringaldazine oxidase was restricted to the two or three outermost developing (lignifying) xylem cell layers, and which responded to competitive inhibitors, such as ferulic acid and ferrocyanide, and to suicide substrates, such as m-chloroperoxybenzoic acid, in a similar way to the Z. elegans basic peroxidase. From these results, we conclude that this Z. elegans basic peroxidase is found at the precise time and place where lignification is occurring, and emerges as the key enzyme involved in the polymerization of sinapyl alcohol and responsible for syringyl-type lignin assembly.
{"title":"Competitive inhibitor-dissected histochemistry of the peroxidase responsible for syringyl lignin biosynthesis in Zinnia elegans xylem","authors":"A. Barceló, F. Pomar, M. Pedreño","doi":"10.1071/PP00071","DOIUrl":"https://doi.org/10.1071/PP00071","url":null,"abstract":"The lignifying xylem from Zinnia elegans hypocotyls gives an intense reaction with the MAule reagent, which is specific for syringyl moieties. The presence of syringyl moieties in the β-O-4 lignin fraction from Z. elegans cell walls was confirmed by thioacidolysis, which gave, as main products, the thioethylated monomers arising from aryl-glycerol-β-aryl ether structures derived from coniferyl and sinapyl alcohols. The guaiacyl/syringyl molar ratio for this lignin fraction was 43/57. Besides β-O-4 syringyl lignins, lignifying Z. elegans hypocotyls also contain a basic peroxidase capable of oxidizing syringyl moieties, such as those present in sinapyl alcohol and syringaldazine, the latter a chromogenic substrate containing the syringyl group specific for angiosperm lignins. Competitive inhibitor-dissected histochemistry of the developing xylem revealed that the stain for syringaldazine oxidase was restricted to the two or three outermost developing (lignifying) xylem cell layers, and which responded to competitive inhibitors, such as ferulic acid and ferrocyanide, and to suicide substrates, such as m-chloroperoxybenzoic acid, in a similar way to the Z. elegans basic peroxidase. From these results, we conclude that this Z. elegans basic peroxidase is found at the precise time and place where lignification is occurring, and emerges as the key enzyme involved in the polymerization of sinapyl alcohol and responsible for syringyl-type lignin assembly.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82852541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent decreases in costs, and improvements in performance, of silicon array detectors open a range of potential applications of relevance to plant physiologists, associated with spectral analysis in the visible and short-wave near infra-red (far-red) spectrum. The performance characteristics of three commercially available ‘miniature’ spectrometers based on silicon array detectors operating in the 650–1050-nm spectral region (MMS1 from Zeiss, S2000 from Ocean Optics, and FICS from Oriel, operated with a Larry detector) were compared with respect to the application of non-invasive prediction of sugar content of fruit using near infra-red spectroscopy (NIRS). The FICS–Larry gave the best wavelength resolution; however, the narrow slit and small pixel size of the charge-coupled device detector resulted in a very low sensitivity, and this instrumentation was not considered further. Wavelength resolution was poor with the MMS1 relative to the S2000 (e.g. full width at half maximum of the 912 nm Hg peak, 13 and 2 nm for the MMS1 and S2000, respectively), but the large pixel height of the array used in the MMS1 gave it sensitivity comparable to the S2000. The signal-to-signal standard error ratio of spectra was greater by an order of magnitude with the MMS1, relative to the S2000, at both near saturation and low light levels. Calibrations were developed using reflectance spectra of filter paper soaked in range of concentrations (0–20% w/v) of sucrose, using a modified partial least squares procedure. Calibrations developed with the MMS1 were superior to those developed using the S2000 (e.g. coefficient of correlation of 0.90 and 0.62, and standard error of cross-validation of 1.9 and 5.4%, respectively), indicating the importance of high signal to noise ratio over wavelength resolution to calibration accuracy. The design of a bench top assembly using the MMS1 for the non-invasive assessment of mesocarp sugar content of (intact) melon fruit is reported in terms of light source and angle between detector and light source, and optimisation of math treatment (derivative condition and smoothing function).
{"title":"Application of commercially available, low-cost, miniaturised NIR spectrometers to the assessment of the sugar content of intact fruit","authors":"Kerry B. Walsh, J. A. Guthrie, Justin W. Burney","doi":"10.1071/PP99111","DOIUrl":"https://doi.org/10.1071/PP99111","url":null,"abstract":"Recent decreases in costs, and improvements in performance, of silicon array detectors open a range of potential applications of relevance to plant physiologists, associated with spectral analysis in the visible and short-wave near infra-red (far-red) spectrum. The performance characteristics of three commercially available ‘miniature’ spectrometers based on silicon array detectors operating in the 650–1050-nm spectral region (MMS1 from Zeiss, S2000 from Ocean Optics, and FICS from Oriel, operated with a Larry detector) were compared with respect to the application of non-invasive prediction of sugar content of fruit using near infra-red spectroscopy (NIRS). The FICS–Larry gave the best wavelength resolution; however, the narrow slit and small pixel size of the charge-coupled device detector resulted in a very low sensitivity, and this instrumentation was not considered further. Wavelength resolution was poor with the MMS1 relative to the S2000 (e.g. full width at half maximum of the 912 nm Hg peak, 13 and 2 nm for the MMS1 and S2000, respectively), but the large pixel height of the array used in the MMS1 gave it sensitivity comparable to the S2000. The signal-to-signal standard error ratio of spectra was greater by an order of magnitude with the MMS1, relative to the S2000, at both near saturation and low light levels. Calibrations were developed using reflectance spectra of filter paper soaked in range of concentrations (0–20% w/v) of sucrose, using a modified partial least squares procedure. Calibrations developed with the MMS1 were superior to those developed using the S2000 (e.g. coefficient of correlation of 0.90 and 0.62, and standard error of cross-validation of 1.9 and 5.4%, respectively), indicating the importance of high signal to noise ratio over wavelength resolution to calibration accuracy. The design of a bench top assembly using the MMS1 for the non-invasive assessment of mesocarp sugar content of (intact) melon fruit is reported in terms of light source and angle between detector and light source, and optimisation of math treatment (derivative condition and smoothing function).","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90388890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new modified pricking technique, a two-pinhole method, was designed to determine the spatial distribution of leaf elongation of grasses. This new technique makes it possible to obtain the distribution profiles of relative elemental growth rates in the growth zone, to evaluate the effect of pricking on the distribution profile of leaf elongation in the growth zone and to decrease the reduction in the elongation rate of grass leaves due to pricking.
{"title":"A two-pinhole technique to determine distribution profiles of relative elemental growth rates in the growth zone of grass leaves.","authors":"Yuncai Hu, U. Schmidhalter","doi":"10.1071/PP00062","DOIUrl":"https://doi.org/10.1071/PP00062","url":null,"abstract":"A new modified pricking technique, a two-pinhole method, was designed to determine the spatial distribution of leaf elongation of grasses. This new technique makes it possible to obtain the distribution profiles of relative elemental growth rates in the growth zone, to evaluate the effect of pricking on the distribution profile of leaf elongation in the growth zone and to decrease the reduction in the elongation rate of grass leaves due to pricking.","PeriodicalId":8650,"journal":{"name":"Australian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81367004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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