Pathways of carbohydrate oxidation in leaves of Pisum sativum and Triticum aestivum

The aim of this work was to establish the pathways of carbohydrate oxidation used in the dark by leaves of Pisum sativum and Triticum aestivum. Segments of young and mature leaves of pea released the carbons of glucose-[¹⁴C] as ¹⁴CO₂ in the order 3,4 > 1 > 2 > 6 whereas in segments of young and mature leaves of wheat the order was 3,4 > 1 > 6 > 2. The detailed labelling of the constituents of mature leaves of wheat by glucose-[1-¹⁴C], -[2-¹⁴C], -[3,4-¹⁴C], and -[6-¹⁴C] was determined and showed that the high yield of CO₂ from C-6 relative to that from C-2 was due to release of C-6 during pentan synthesis. Estimates were made of the maximum catalytic activities of phosphofructokinase and glucose-6-phosphate dehydrogenase in pea and wheat leaves of three ages. The results of all the above investigations strongly indicate that both pea and wheat leaves in the dark oxidize carbohydrate via glycolysis and the pentose phosphate pathway with the latter accounting for no more than a third of the total. No evidence was obtained of any major change in the relative activities of the two pathways during the development of either type of leaf.     

Epicuticular wax of Poa ampla leaves

Leaf wax of a glaucous variety of Poa ampla contains hydrocarbons (5%, C₂₃–C₃₅), esters (9%, C₃₆–C₅₆), free acids (3%, C₁₆–C₃₄), free alcohols (6%, mainly C₂₆); hentriacontane-14,16-dione (14%), 5-oxohentriacontane-14,16-dione (1%); hydroxy β-diketones (56%) and unidentified material (6%). The hydroxy β-diketones, which are more abundant in this wax than in others, were shown by ¹³C NMR to consist of 4-hydroxy (15%), 5-hydroxy (70%) and 6-hydroxy (15%) hentriacontane-14,16-diones.     

Dammarane saponins of leaves of Panax pseudo-ginseng subsp. himalaicus

From dried leaves of Panax pseudo-ginseng subsp. himalaicus collected in Eastern Himalaya, new dammarane saponins, named pseudo-ginsenosides-F₁₁ and -F₈ were isolated along with the known Ginseng-root saponins, ginsenosides-Rb₃, Rd and -Re. Pseudo-ginsenoside-F₈ was proved to be a mono-acetyl-ginsenoside-Rb₃ and the location of its acetyl group was established mainly by ¹³C NMR spectroscopy. Pseudo-ginsenoside-F₁₁, was identified as the 6-O-α-rhamnopyransyl(1 → 2)-β-glucopyranoside of 3β,6α,12β,25-tetrahydoxy-(20S,24R)-epoxy-dammarane. The C-24 configuration of ocotillone and its related triterpenes was confirmed to be 24R excluding the recent comment by Lavie et al.     

木姜子叶精油的化学成分研究

采用气相色谱-质谱联用仪对产于秦岭太白山的木姜子叶的挥发油成分进行分析鉴定,从分离出的79个峰中鉴定了32种成分,其含量占挥发油总量的90.59％,主要成分为1,3,3-三甲基-乙-氧杂双环[2,2,2]辛烷(59.96％),1,8-桉油醇(8.96％),香茅醛(6.86％),2-甲基-5-(1-甲基乙烯基)环己酮(4.34％)和澄花醇乙酯(3.19％)。     

Morphological adaptions of Quercus ilex leaves in the Castelporziano forest

The annual course of vegetative growth of the most representative species of a Quercus ilex L. forest in Castelporziano (Latium, Italy) was studied through periodical analysis of selected ecophysiological leaf indexes, for the period 1987–1990. The results demonstrate that the local climate facilitates continuous vegetative activity of the sclerophyllous species without a latent phase. The variable morphology of sun and shade leaves of Q. ilex illustrates the plant's response to environmental stress.     

A chemotaxonomic survey of flavonoids in leaves of the Oleaceae

Leaves of 97 taxa representing all the genera at present recognized in the family Oleaceae were surveyed for flavonoids. Four flavonol glycosides were found to be common, the 3-glucmides and 3-rutinosides of quercetin and kaempferol, as were four flavone glycosides, namely the 7-glurosides arid 7-rutinosides of luteolin and apigenin. Among rarer constituents detected were luteolin 4'-glucoside, eriodictyol 7-glucoside, chrysoeriol 7-glucoside, an apigenin-di-C-glycoside and several higher glycosides of quercetin. The species and genera surveyed fell into two groups: those with flavonol glycosides alone; and those with both flavonol and flavone glycosides. The most striking correlation was with chromosome number (and subfamily division) since almost all taxa with a basic number of 11, 13 and 14 had only flavonol glycosides, whereas most taxa with x = 23 had both types of flavonoid. Evolutionary advancement in the family appears to involve the gradual replacement of flavonol by flavone glycosides. Indeed, a few tam, notably Nestegis apelala, Picconia excelsa and Tesserandra fluminense , lacked flavonol glycosides in the leaves completely. At the lower levels of classification, the distribution of flavonoids is of less interest. However, the patterns in Linociera and Chionanthus , two taxa recently made congeneric, are sufficiently different to suggest that this decision might have to be reconsidered when more is known of their chemistry. Otherwise leaf patterns generally fit in with the existing generic classification in the family.     

Properties of acyl hydrolase enzymes from Phaseolus multiflorus leaves

The properties of acyl hydrolase enzymes purified from the leaves of Phaseolus multiflorus have been studied. Hydrolase I which deacylates phosphatidylcholine and oleoylglycerol had a pH optimum towards phosphatidylcholine of 5.3. Hydrolase II which deacylates glycosylglycerides and oleoylglycerol showed pH optima of 7.3 (monogalactosyldiglyceride, MGDG) and 4.3 (sulphoquinovosyldiglyceride, SQDG). Both enzymes showed activity peaks towards oleoylglycerol at pH 6.8 and 8.8. Unesterified fatty acids and Triton X-100 inhibited the rate of SQDG hydrolysis while bovine serum albumin increased activity. An apparent K_m for SQDG of 0.15 mM was found. Hydrolase II catalysed transmethylation of liberated fatty acids during the hydrolysis of oleoylglycerol when methanol was included in the assay system. A number of salts inhibited SQDG hydrolysis but their effect on oleoylglycerol was less consistent. The position of ester cleavage of oleoylglycerol was determined by the use of H₂¹⁸O. Cell-free extracts from P. multiflorus leaves degraded SQDG as far as sulphoquinovose.     

Effect of light and temperature on epicuticular fatty acid and fatty alcohol of tobacco

Genetically uniform burley tobacco (Nicotiana tabacum) was grown under field and various controlled-environment conditions to determine whether environment influenced epicuticular alkane, fatty acid, and fatty-alcohol composition of the leaves. Quantity and quality of alkanes, fatty acids, and fatty alcohols were greatly influenced by environmental conditions. Highest light intensity did not result in the largest total long aliphatic carbon-chain production. Generally, long photoperiod and cool temperature were associated with highest long aliphatic carbon-chain production on a leaf area basis. Quantity of the individual alkane, fatty acid, or fatty alcohol classes present under the different growth conditions varied in relation to the leaf metabolic status and not leaf size.     

Alkali solubility of hemicelluloses in relation to delignification

The polysaccharide composition of bark from Pinus radiata, Salix fragilis, and Populus euramericana has been determined. All the barks contained lower levels of cellulose and hemicellulose than the corresponding woods; cellulose: hemicellulose ratios were also lower in the barks. Alkali extracted all of the hemicellulose-A but only half of the hemicellulose-B from P. radiata bark without prior delignification. Similar alkaline extraction removed almost all of the hemicellulose (A + B) from ryegrass leaves without delignification. With the other samples tested only a part of the hemicellulose A and B is extracted without delignification. It is suggested that the polysaccharide so extracted represents wall hemicellulose which is not linked to lignin or other wall constituents by alkali-stable links.     

Terpenes of Podocarpus lambertius

Sitosterol and the following terpenic compounds have been isolated from the bark of Podocarpus lambertius: 3β-hydroxytotarol, 4β-carboxynortotarol, and macrophyllic and lambertic acids. The leaves yielded sitosterol, stigmastan-3β,5α-diol-6-one, isopimaric acid, phyllocladene, isophyllocladene, 8,9-abieten-15-ol and 17-isophyllocladenol.