Rapid, Micro-Methods to Estimate Plant Silicon Content by Dilute Hydrofluoric Acid Extraction and Spectrometric Molybdenum Method

By treating 0.5 g DW of a plant sample directly with 10 ml of a dilute hydrofluoric acid solution (HF solution, 1.5 M HF—0.6 M HCl), all the silica in plant (as much as 150 mg SiO₂) was dissolved within 1 h. After dilution of the extract with 40 mL of distilled water, the silica in the extract was measured by the spectrometric molybdenum yellow method. The molybdenum yellow method, in which silica in 0.1 mL of the diluted extract can be determined in 8 min, is well suited to rapid, micro-estimations of the silica content in plants. In the micro-modification, the size of the plant sample was reduced to 100 mg DW. The analytical procedure was simple, and the analytical time was less than 2 h. The method can save much labor and time, compared with the gravimetric analysis. The dissolution with HF solution and the molybdenum yellow method were also applied to the measurement of the content of silica separated by acid digestion of rice plants. Excellent agreement in the silica measurement of rice plants was confirmed among the direct extraction method, the gravimetric method and the digestion-separation-dissolution method. In the molybdenum yellow method, the addition of boric acid enabled to mask the interference of hydrofluoric acid, and the least amount of citric acid required for the elimination of phosphorus interference was proposed. In conclusion in this report, recommended methods for the rapid estimation of the silica content in rice plants were presented.     

套袋对鸭梨果实香气及糖酸组分的影响

采用静态顶空和气相色谱-质谱联用技术、高效液相色谱技术,研究了生长期套袋对鸭梨果实挥发性成分、糖酸组分等风味物质的组成和含量的影响。结果表明:套袋导致鸭梨香气物质种类减少和相对百分含量降低。套袋鸭梨采收时测定的香气成分有3类18种,其中酯类15种、烯类2种、醇类1种;不套袋鸭梨采收时测定的香气成分有3类26种,其中酯类23种、烯类2种、醇类1种。鸭梨的主要香气成分是乙酸己酯、己酸乙酯、丁酸乙酯。套袋和不套袋鸭梨均检测到3种糖、4种有机酸组分,其中糖组分主要为果糖,其次为蔗糖、葡萄糖,有机酸组分主要为苹果酸,其次为乙酸、柠檬酸、草酸,但不同处理间含量存在差异。     

Responses of Rice Genotypes Carrying Different Dwarf Genes to Fusarium moniliforme and Gibberellic Acid

Abstract

A total of 32 rice genotypes carrying different dwarf or semi-dwarf genes were inoculated with the fungus Fusarium moniliforme Sheldon or treated with 50 mg l-¹ GA₃ in order to select resources resistant to rice bakanae disease from the dwarf materials. The length of the elongated seedlings was measured, and the percentage of death of the seedlings after transplanting to field was also counted. A significant correlation was found between the length of the seedling treated with GA₃ and disease injury by bakanae fungus. Rice materials carrying dwarf gene such as sd1 were not only sensitivity to GA₃ but also susceptive to rice bakanae disease. Materials carrying dwarf gene d1 were insensitive to GA₃ but susceptive to bakanae. On the other hand, all materials carrying d29, sd6 or sdq(t) genes showed resistance to bakanae. The present study indicated that dwarf and semi-dwarf rice materials might be useful resources for improvement of bakanae resistance in rice breeding programs.     

Vegetative propagation of Aesculus indica through stem cuttings treated with plant growth regulators

Cuttage propagation of Aesculus indica was tested by treatments with different concentrations of indole-3-acetic acid (IAA) @ 2000, 4000 (ppm), indolebutyric acid (IBA) @ 2000, 4000 (ppm) and naphthlcetic acid (NAA) @ 2000, 4000 (ppm) in dry formulation in the Forest Nursery, Faculty of Forestry, SKUAST-K, Shalimar. The cuttings treated with IBA @ 4000 ppm and IBA @ 2000 ppm had a sprouting rate of 75% and 50%, respectively, which was significantly higher than that of control and other treatments. The highest rooting rate (50%) was recorded in the cuttings with the application of IBA @ 4000 ppm. The cuttings treated with IBA @ 2000 ppm had 25% rooting rate. All other treatments along with control (talc powder) failed to induce rooting. It was concluded that IBA @ 4000 ppm was a better-applied concentration for vegetative propagation of A. indica under Kashmir conditions. Biography: Mumtaz Majeed (1980– ), male, post graduate in Faculty of Forestry, Sher-e-Kashmir University of Agricultural Science & Technology, Shalimar, Srinagar - 191 121, J&K, India.     

Ozone,Acid Deposition,and Mycorrhization Effects on Loblolly Pine and White Oak

Abstract

Above- and below-ground responses of juvenile loblolly pine (Pinus taedaL.) and white oak (Quercus albaL.) to tropospheric ozone (0.0, 0.06, and 0.12 μL L^-1 O₃), acid precipitation (pH 4.8, 4.2, and 3.6), and induced ectomycorrhizal colonization (Pisolithus tinctorius [Pers.] Coker & Couch vs. natural mycobiont), alone and in combination, were examined. After 30 weeks, the filtered air treatment (ozone 0.0) reduced foliar injury but also produced smaller stem diameters, lower total foliage and total shoot dry weights, decreased needle density, and shorter root systems in inoculated pine, growth responses not found in uninoculated pine. Height growth of inoculated oak was increased by the filtered air treatment while leaf density was reduced by 0.12 μL L^-1 O₃, results also not found in uninoculated oak. Ectomy-corrhizal colonization percentages in pine decreased with increasing O₃ concentration regardless of mycorrhizal treatment, and the filtered air treatment produced the highest infection percentages in inoculated oak as well. Rains of pH 4.2 stimulated height growth in inoculated pine while diameter decreased in inoculated oak but increased in uninoculat-ed oak with declining pH. Also, pH 4.2 rainfall increased root weight in inoculated oak while that of pH 4.8 reduced foliar injury but also shoot weight in oak regardless of mycorrhizal treatment. Generally, the my-corrhization response to increasing rainfall acidity was reduced colonization. Independent of the other treatments, inoculation produced a substantial increase in above- and below-ground growth of both pine and oak, and also increased foliage density but reduced specific root length in each species. Overall, these results indicate that the growth responses to O₃ and acid deposition of loblolly pine and white oak are strongly influenced by mycorrhization, but that the magnitude of these responses is exceeded by those to mycorrhization alone. However, the propensity revealed here for both O₃ and acid precipitation to suppress mycorrhizal colonization in these two species may indicate the potential for a gradual reduction in long-term forest productivity in the southeastern United States.     

Slash pine (Pinus elliottii Engelm.) somatic embryogenesis II. Maturation of somatic embryos and plant regeneration

Maturation of slash pine (Pinus elliottii Engelm.) somatic embryos was achieved using two protocols, each starting with a different agar incubation step to deplete plant growth regulators (PGRs) used in previous cultural steps. Strength of maturation medium (single vs. double) was found important in the first protocol to develop normal, mature embryos. In the second protocol, abscisic acid (ABA) concentrations (0, 15 and 30 M) and carbohydrate sources were tested for embryo maturation. Thirty M ABA and 6% maltose were deemed the best combination. Embryo germination was accomplished in a continuously lighted environment and embryos receiving a cold pretreatment (4 °C in darkness for 16 days) germinated better than embryos which did not receive cold pretreatment. With a survival rate of 33% after acclimation in a mist system, more than 25 plants from somatic embryos have been established in a greenhouse. Incompletely germinated embryos (lacking roots) were rooted via adventitious rooting techniques and subsequently established in the greenhouse. All established plants obtained from somatic embryogenesis appear normal in morphology.     

Sorption of Cr(VI) on the wood of Japanese larch treated with concentrated sulfuric acid

A carbonaceous sorbent was prepared from the wood of Japanese larch (Larix leptolepis) by dehydration with concentrated sulfuric acid in a 69% yield. The abilities of the sorbent to remove Cr(VI) from aqueous solutions were investigated. Research parameters included the initial solution pH, temperature, and initial concentration of Cr(VI) in solution. The removal of Cr(VI) was highly solution pH dependent and was mainly governed by physicochemical sorption under weak acidic conditions. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated at different temperatures, and the sorption capacity increased with rising temperature, indicating the endothermic nature of the Cr(VI) sorption onto the sorbent. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible, owing to strong interaction of HCrO ₄ ⁻ with the active sites of the sorbent.     

Termiticidal activity of wood vinegar, its components and their homologues

The termiticidal activity of wood vinegar, its components, and their homologues have been studied. Three kinds of wood vinegar made from the mixed chips ofCryptomeria japonlca andPseudotsga menziesii (wood vinegar A),Quercus serrata (wood vinegar B), andPinus densiflora (wood vinegar C) exhibited high termiticidal activities againstReticulitermes speratus. Acetic acid, which is the largest content of wood vinegar, exhibited high termiticidal acitivity. The contents of organic fraction of wood vinegars and acetic acid might be responsible for the differences in termiticidal activities among these wood vinegars. The structure and termiticidal activity relations of phenols were studied. Phenol with some substituents revealed higher termiticidal activity than benzene derivatives, which have no hydroxyl group; an ortho substituent of phenol plays an important role in termiticidal activity. It has become apparent that high termiticidal activity cannot be obtained by a phenolic hydroxyl group alone; it can be obtained, however, by some substituents, especially an ortho substituent in addition to a phenolic hydroxyl group. The bulkiness of the substituent at the ortho position participates in termiticidal activity; activity decreases as the size of an ortho substituent increases. It is thought that the interaction at the receptor site of termites is affected by the increased size of the ortho substituent.     

Influence of synthetic plant growth substances on the survivorship and developmental parameters of <Emphasis Type="Italic">Spilarctia obliqua</Emphasis> Walker (Lepidoptera: Arctiidae)

The nontarget effects of three plant growth stimulants (gibberellic acid, Siapton and triacontanol) and two plant growth retardants (chlormequat chloride and mepiquat chloride) on the survivorship and developmental parameters of Spilarctia obliqua Walker (Lepidoptera: Arctiidae) were studied. For each compound, various concentrations (0.125×, 0.25×, 0.5×, × , 2× and 4×; × = labeled dose) bracketing the labeled dose were prepared by serial dilution and mixed with an artificial diet for the insect. Gibberellic acid caused an increase in the larval period at × − 4×, but no marked difference was observed in the pupal period or in larval survival at any concentration. Siapton induced a significant increase in larval period at the two highest doses but caused significant reduction in pest survival at × − 4×. Interestingly, triacontanol induced a significant reduction in pest survivorship at almost all doses. The LC₅₀ for triacontanol was 0.206% and LT₅₀ was 266.5 hours at the labeled dose. However, triacontanol did not cause any significant difference in larval or pupal periods at any dose tested. Chlormequat chloride and mepiquat chloride caused significant reduction of larval survivorship at concentrations higher than the labeled doses, and no effect on the larval period. Intriguingly, a significant reduction in pupal period was observed with chlormequat chloride at × and 0.25×. Based on the marked effect of triacontanol on pest survivorship, this study suggests incorporating triacontanol in integrated pest management modules for S. obliqua. Caution in the use of gibberellic acid and Siapton for pest infestations is also indicated.     

Distribution of gymnemic acid in various organs of Gymnema sylvestre

The gymnemic acid contents in various organs of Gymnema sylvestre were investigated by High Performance Liquid Chromatography (HPLC) method. The results shows that the content of gymnemic acid in various organs, obviously different, was 54.29, 31.66, 28.82, 27.67, 25.39, 20.56 and 1.31 mg·g⁻¹ DW in shoot tips, flowers, nodes, leaves, internodes, roots and seeds, respectively. The highest gymnemic acid content (54.29 mg·g⁻¹ DW) was found in shoot tip, 1.96 fold higher than that in leaves (27.67 mg·g⁻¹ DW). Maximum quantity of gymnemic acid (35.39 mg·g⁻¹ DW) was observed in the young leaves, which was 1.52 times higher than that in old leaves (23.07 mg·g⁻¹ DW). The content of gymnemic acid in young, middle and old internodes was 26.47, 25.77 and 23.94 mg·g⁻¹ DW, respectively, all lower than that in leaves (27.67 mg·g⁻¹ DW), whereas the content of gymnemic acid in young, middle and old nodes was 27.96, 28.81 and 29.66 mg·g⁻¹ DW, respectively, all higher than that in leaves. The study provides the scientific evidences for the rational development and utilization of Gymnema sylvestre resources, since over exploitation of natural stands has caused depletion of these plants in nature. Foundation project: This work was supported by University Grants Commission, New Delhi (No. 33-88/2007 (SR))