Comparative greenhouse study of Eucalyptus grandis in vitro plantlets and half-sib seedlings,I. Net photosynthesis

Tissue culture-derived plantlets from three superior five-year-old Eucalyptus grandis Hill ex Maid hybrids were compared to their related half-sib seedlings under greenhouse conditions. Net photosynthesis, chlorophyll a and b concentrations, and nitrogen concentration were sampled four times at 40-day intervals. Comparisons were started 40 days after plantlets and germinating seedlings were moved from mist to greenhouse conditions. Seedlings had higher net photosynthesis, chlorophyll and nitrogen concentration at early harvests. However, as the study progressed the difference between plantlets and seedlings decreased and reached similar values. No family differences were observed regardless of plant origin (seedlings or plantlets). Plantlets and seedlings showed similar general trends in all the measured parameters over the four harvests.     

Nitrate reductase activity and nitrate accumulation in in vitro produced axillary shoots,plantlets and seedlings of Pinus pinaster

The initial and induced in vivo Nitrate Reductase Activity, the nitrate accumulation by in vitro-produced axillary shoots and plantlets of Pinus pinaster were compared respectively with those of shoots collected from seedlings and whole plants.The usefulness of the nitrate of the medium used for in vitro axillary shoot formation is demonstrated by the occurrence of initial NR activity in the explants. When fed in a non in vitro situation with a 50 mM KNO₃ solution, they have the same induced capacity to reduce nitrate as do shoots from seedlings, even though the latter accumulate less nitrate. Plants regenerated in vitro exhibit an ability to reduce nitrate similar to that of seedlings. In both types of plants, the Nitrate Reductase potential is greater in roots than in shoots.Abbreviation NR Nitrate Reductase - BA 6-Benzyladenine     

FACE水稻干物质积累与分配模型

借助中国唯一的FACE技术平台,通过设置不同的N肥处理,研究了FACE条件下水稻干物质积累及分配动态的模拟模型.模型以生理发育时间为驱动因子,以CO₂浓度函数为主要影响因子,同时引入N素影响因子调节干物质的积累与各器官分配指数.模拟结果表明,随着大气CO₂浓度的增加,水稻地上部总干物重显著增加,叶干重分配指数下降,穗干重分配指数基本不变,茎干重分配指数前期增加,后期持平.通过不同年份试验数据对模型的验证,预测根均方差（RMSE）较小,且相关系数均达到了极显著水平.表明模型拟合程度高,具有较好的适应性和预测性.     

温度、光辐射及水分对温室甜瓜幼苗干物质积累与分配的影响及其模拟模型

利用分期播种法和灌溉上限法,研究了温度、光辐射和水分等环境因子对温室甜瓜幼苗植株干物质积累与分配的影响,并基于积温学原理,综合环境其他因子,模拟建立了甜瓜幼苗受有效积温、日温差积累、光辐射积累等多因子驱动的干物质积累与分配模型．结果表明：周年不同播期,随着有效积温、光辐射积累及不同灌溉水分上限的变化,甜瓜幼苗期植株干物质积累和分配分别呈指数函数和二次抛物线函数变化,但不同播期及水分处理函数常数不同．综合分析认为,干物质积累和分配模型分别为有效积温驱动下的指数函数和二次抛物线函数,常数项均由日温差积累和光辐射积累驱动,它们之间为一次函数关系．验证结果表明,该模型能较为真实、客观地模拟植株干物质积累与分配变化过程,对甜瓜苗期生长分析与生产管理具有应用价值．     

The impact of mycorrhizal colonization upon nitrogen source utilization and metabolism in seedlings of Eucalyptus grandis Hill ex Maiden and Eucalyptus maculata Hook

Analysis of soil solution from forest sites dominated by Eucalyptus grandis and Eucalyptus maculata indicates that soluble forms of organic nitrogen (amino acids and protein) are present in concentrations similar to those of mineral nitrogen (nitrate and ammonium). Experiments were conducted to determine the extent to which mycorrhizal associations might broaden nitrogen source utilization in Eucalyptus seedlings to include organic nitrogen. In isolation, species of ectomycorrhizal fungi from northern Australia show varying abilities to utilize mineral and organic forms of nitrogen as sole sources. Pisolithus sp. displayed strongest growth on NH₄⁺, glutamine and asparagine, but grew poorly on protein, while Amanita sp. grew well both on mineral sources and on a range of organic sources (e.g. arginine, asparagine, glutamine and protein). In sterile culture, non-mycorrhizal seedlings of Eucalyptus grandis and Eucalyptus maculata grew well on mineral sources of nitrogen, but showed no ability to grow on sources of organic nitrogen other than glutamine. In contrast, mycorrhizal seedlings grew well on a range of organic nitrogen sources. These observations indicate that mycorrhizal associations confer on species of Eucalyptus the ability to broaden their resource base substantially with respect to nitrogen. This ability to utilize organic nitrogen was not directly related to that of the fungal symbiont in isolation. Seedlings mycorrhizal with Pisolithus sp. were able to assimilate sources of nitrogen (in particular histidine and protein) on which the fungus in pure culture appeared to grow weakly. Experiments in which plants were fed ¹⁵N-labelled ammonium were undertaken in order to investigate the influence of mycorrhizal colonization on the pathway of nitrogen metabolism. In roots and shoots of all seedlings, ¹⁵N was incorporated into the amide group of glutamine, and label was also found in the amino groups of glutamine, glutamic acid, γ-aminobutyric acid and alanine. Mycorrhizal colonization appeared to have no effect on the assimilation pathway and metabolism of [¹⁵N]H₄⁺; labelling data were consistent with the operation of the glutamate synthase cycle in plants infected with either Pisolithus sp. (which in isolation assimilates via the glutamate synthase cycle) or Elaphomyces sp. (which assimilates via glutamate dehydrogenase). It is likely that the control of carbon supply to the mycorrhizal fungus from the host may have a profound effect on both the assimilatory pathway and the range of nitrogen sources that can be utilized by the association.     

Diversity and distribution of co-infecting Botryosphaeriaceae from Eucalyptus grandis and Syzygium cordatum in South Africa

Species in the fungal family Botryosphaeriaceae are latent pathogens on woody trees. These fungi often have a wide host range, which can include native and introduced hosts in an area. Multi-locus DNA sequence identification on a recent collection of Botryosphaeriaceae from Eucalyptus grandis and Syzygium cordatum trees in South Africa revealed cross-infectivity of several species, novel host associations and new country reports. Neofusicoccum eucalyptorum, Neofusicoccum kwambonambiense, Neofusicoccum parvum, Neofusicoccum australe and Lasiodiplodia pseudotheobromae were identified from both tree species, with L. pseudotheobromae and N. eucalyptorum isolated for the first time from S. cordatum, similar to N. kwambonambiense from Eucalyptus. This also represents the first report of L. pseudotheobromae from South Africa. Botryosphaeriaceae species on Eucalyptus species and S. cordatum are fairly well known from South Africa. However, this study revealed new associations, indicating that conclusions should not be generalized and that more intensive sampling from different areas and over time is likely to reveal distinct species and host association patterns.     

Development, characterization and mapping of microsatellite markers in Eucalyptus grandis and E. urophylla

 We report on the development, genetic characterization and linkage mapping of a battery of SSR (simple sequence repeat) loci in Eucalyptus grandis and E. urophylla. This study reveals the abundance of SSRs in Eucalyptus, the very high information content of these markers for mapping and individual identification, and demonstrates the feasibility of constructing a comprehensive microsatellite-based linkage map for Eucalyptus. Primer sequence for a set of 20 highly informative EMBRA (Eucalyptus microsatellites from Brazil) loci are made available together with their map position and estimates of the expected heterozygosity and allele size range in these two species. Using genomic library enrichment and anchored-PCR screening prior to sequencing, the efficiency of SSR marker locus development was 63% from sequencing data to operationally useful SSR loci. Absolute transportability between the two species and very high levels of allelic variability and expected heterozygosity (H) were seen at all SSR loci surveyed. The number of alleles per locus ranged from 9 to 26 with an average of 16.3±4.8. The average H of 15 loci was 0.86±0.04, 0.83±0.08 and 0.89±0.04, respectively, for E. urophylla, E. grandis and the combined two-species estimate. In the mapping analysis 16 out of 20 marker loci segregated in a fully informative configuration, allowing the determination of synteny of six homologous linkage groups between the two species. The availability of transportable, multiallelic, PCR-based co-dominant SSR loci represents a dramatic improvement in our ability to carry out detailed population genetic analysis and to search, understand, and manipulate allelic variation at QTLs (quantitative trait loci) in species of Eucalyptus. Received: 16 March 1998 / Accepted: 22 March 1998     

Effect of lanthanide chloride on photosynthesis and dry matter accumulation in tobacco seedlings

To investigate the physiological effects of rare earth ions, we have studied the effect of LaCl₃ on the photosynthetic light reactions in tobacco (Nicotiana tobacum). When treated with 5–20 mg/L LaCl₃ in Hoagland solution by water culture, the dry matter accumulation of different parts in tobacco, the content of chlorophyll increased gradually, but decreased when the concentration of LaCl₃ was ≥ 50 mg/L. The optimum concentration for growth appeared to be about 20 mg/L of LaCl₃ in nutrient solution. La³⁺ promoted the activities of the Hill reaction, Mg²⁺-ATPase, and stimulated the rate of photophosphorylation in chloroplast at low concentrations, but inhibited them at high concentrations. It is concluded that La³⁺ stimulated the growth of tobacco seedlings and accelerated the photosynthetic light reactions at suitable concentration in vivo.     

Similarity of growth patterns between plantlets and seedlings of Brassica campestris L. under different in vitro environmental conditions

Explants and seeds of Brassica campestris L. were cultured on Murashige & Skoog (1962) medium with and without sucrose in a vessel with different numbers of air changes per hour under different PPF (photosynthetic photon flux) conditions. The growth and development of plantlets in the vessel were similar to those of seedlings when cultured under the same in vitro environmental conditions. The growth and development of seedlings when cultured under the same in vitro environmental conditions. The growth and development of plantlets/seedlings were greater for treatments with a higher number of air changes per hour and a higher PPF regardless of the sucrose concentration in the culture medium.The CO₂ concentration in the vessel with a lower number of air changes per hour decreased to approximately 100 ppm during the photoperiod on day 21 due to the photosynthetic activities of the plantlets/seedlings. The low CO₂ concentration, in turn, reduced the net photosynthetic rate of plantlets/seedlings in the vessel, and thus affected their growth and development.Abbreviations C_in CO₂ concentration in the culture vessel - C_out CO₂ concentration in the culture room - MS mineral composition of Murashige & Skoog (1962) medium - PPF photosynthetic photon flux     

Dry mass partitioning and nitrogen uptake by Eucalyptus grandis plants in response to localized or mixed application of phosphorus

Plants respond to nutrient rich patches by changing root morphology and physiology. The aim of this paper was to analyze shoot and root growth of Eucalyptus grandis plants fertilized with the same amount of phosphorus applied in two different ways: thoroughly mixed in the soil or localized in a single hole near the plant. Localized fertilization increased root mass in the zone where fertilizer was applied, but total root mass was not altered by the type of fertilization application. With mixed fertilization plant growth was less than with localized fertilization, and plants showed nitrogen deficiency. Nitrogen uptake was measured in a split-root hydroponics system where phosphate was applied to the whole root system or in part of it. Growth of plants receiving phosphorus in the whole root system was limited by nitrogen uptake, as was revealed by low leaf N and low nitrate uptake. In conclusion, the positive effect of localized application of phosphorus must be ascribed not only to higher phosphorus but also to sustained nitrogen assimilation.     

Dynamics of uptake, distribution and utilization of nitrogen applied at different times after planting in a Eucalyptus grandis plantation

N fertilizer labelled with ¹⁵N was used to follow the accumulation and distribution of N applied at different times after planting Eucalyptus grandis W Hill ex Maiden seedlings in south-eastern Queensland, Australia. The first application was made to selected trees at 0.12 y after planting (T₀), and treated trees were harvested at intervals after. Further labelled applications were made on different sets of trees 0.50, 0.74, 1.30 and 1.49 years after T₀; T_0.5, T_0.74, T_1.30 and T_1.49 respectively. After 0.5 y there was no significant difference in growth between T₀ trees and unfertilized controls, but after 1 y above-ground biomass and N content of the controls was only 30% and 39% of the fertilized trees respectively (P <0.05). At later applications controls were not significantly different from fertilized trees up to 1 y later, but after 2 y above-ground biomass and N content was reduced (P <0.05). Growth reductions occurred after leaves present on the tree at the time of fertilizer application were shed. Leaf biomass and N content increased steadily to age 1.5 y and then stabilized at about 2.5 kg tree^-1 and 35 g tree^?1 respectively, new growth balanced by litter fall. N content in woody material (stems+branches) increased steadily, equaling that of the leaves at 3.5 y. N derived from fertilizer and the proportion of applied N recovered peaked at 1 y and then decreased. These relationships were not affected by time of application. In T₀ trees N in above-ground parts derived from fertilizer increased steadily to 42% of the total 0.5 y after application. It then decreased rapidly after leaf fall commenced while total N content increased. When observations ceased 3.5 y after planting, less than 5% of the N in the trees was derived from fertilizer. N uptake was two-phased. In the first year mineral N from the fertilizer was taken up by the trees. In subsequent years fertilizer contributed to the tree growth but the N taken up came from a different source.     

巨尾桉叶中皂苷的提取分离及其抗氧化活性研究

开展了从巨尾桉叶中提取皂苷的工艺优化研究.考察了温度、时间,溶剂用量对皂苷得率的影响,并对粗提物进行纯化.结果表明,巨尾桉叶皂苷的优化条件是:提取温度61.8℃,提取时间5.02h,溶剂与巨尾桉叶的液料比为20.09∶1,皂苷的提取得率(g/g)为5.51％.提取物经大孔树脂-丙酮沉淀联用分离法纯化后皂苷含量由16.22％提高到50.35％.对粗提物、大孔树脂纯化物和大孔树脂吸附-丙酮沉淀纯化物进行抗氧化活性研究.结果表明,它们对DPPH自由基的最大清除率分别为83.02％、84.20％和85.62％,对过氧化氢的最大清除率分别为80.10％、55.02％和48.21％,对超氧阴离子自由基的最大清除率分别为16.62％、13.43％和10.01％.     

Dry matter and nitrogen accumulation and partitioning in selected soybean genotypes of different derivation

Summary Experiments were conducted to determine if changes in the accumulation and partitioning of dry matter (DM) and nitrogen (N) in soybean [Glycine max (L.) Merr.] were associated with agronomic improvements and to assess the degree of genetic variation present for these traits. Fifteen maturity group II soybean genotypes including three ancestral cultivars, three modern cultivars, and nine agronomically superior plant introductions (PI's) were grown in replicated tests at four locations in the eastern U.S. The DM and N of stems, pod walls, and seeds were determined at maturity, and the apparent harvest indices (HI) and the apparent nitrogen harvest indices (NHI) were calculated. Pod DM partitioning was calculated as the ratio of seed DM to total pod DM and pod N partitioning was the ratio of seed N to total pod N. The mean DM accumulation of the modern cultivars was significantly greater than that of the ancestral cultivars and PI's. The apparent HI and the pod DM partitioning of both the modern and ancestral cultivars were significantly higher than that of the PI's. The three modern cultivars demonstrated the highest N accumulation. As a group, the modern cultivars consistently showed maximal accumulation and partitioning of DM and N suggesting that these physiological traits are associated with agronomic improvement. No individual PI was found to possess DM or N accumulation or partitioning which significantly exceeded the best modern cultivar or ancestral cultivar, indicating that genotypes with accumulation or partitioning characteristics which exceed available germplasm may be difficult to identify. Seed yield was correlated (P<0.05) with both DM (r=0.61) and N (r=0.57) accumulation.     

The effect of aluminium on the distribution of calcium,magnesium and phosphorus in mycorrhizal and non-mycorrhizal seedlings of Eucalyptus rudis: a cryo-microanalytical study

The distribution of Al, Ca, Mg and P in the lateral roots and leaves of mycorrhizal and non-mycorrhizal seedlings of Eucalyptus rudis grown with and without Al was analysed using energy-dispersive X-ray microanalysis on a cryo-scanning electron microscope. Al accumulated in all tissues of nonmycorrhizal plants: the endodermis was not a barrier to the translocation of Al. In mycorrhizal roots, Al was concentrated within the sheath. The presence of Al reduced the levels of Ca and Mg in both mycorrhizal and non-mycorrhizal roots and shoots in comparison with control plants. The presence of mycorrhizas increased the levels of Ca and Mg in plants grown with Al in comparison with non-inoculated plants, although there was no evidence that mycorrhizas increased the levels of P in plants grown in Al-amended soils. P levels were higher in the mycorrhizal sheath of plants grown with Al than the controls.     

Compared root system architectures in seedlings and in vitro plantlets of Hevea brasiliensis,in the initial years of growth in the field

In vitro culture of Hevea was undertaken to propagate selected clones on their own roots. The challenge was to overcome the failure of cuttings due to the poor conformity of regenerated root systems. Trees of several juvenile or mature genotypes were propagated either by in vitro microcutting, or by somatic embryogenesis, and planted in the field. Certain static and dynamic components of the root system were observed at different growth stages, from 0 to 3 years, and compared to those of seedlings of the same age used in the trial as a reference. A simple method was designed for measuring the vigour and balance of the root system. The in vitro plantlets had a well-developed taproot and lateral root system, with an architecture similar to that of plants obtained from seed. Moreover, clear differences occurred between selected clones for the relative vigour of the tap roots, lateral roots and trunk. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparative effectiveness of cattle manure, poultry manure, phosphocompost and fertilizer-NPK on three cropping systems in vertisols of semi-arid tropics. II. Dry matter yield, nodulation, chlorophyll content and enzyme activity

A field experiment was conducted on a deep Vertisol of Bhopal, India to compare root and shoot biomass, chlorophyll content, enzyme activity and nodulation in three cropping systems at three combinations of organic manure and inorganic-fertilizer: 75%NPK + 5 t farmyard manure (FYM), 75%NPK + 1.5 t poultry manure (PM), and 75%NPK + 5 t phosphocompost (PC) vis-a-vis 0%, 75% and 100% of fertilizer-NPK. In general, nodule number and its mass were lower in intercrop soybean than sole soybean. Also there was decrease in the nodule number with higher NPK dose. The FYM treated plots recorded 22.0% and 7.6% higher nodule mass than poultry manure and phosphocompost plots, respectively. Also, the total chlorophyll content was higher in organically treated plots than that in 100% NPK particularly at 30 days after sowing (DAS, pre-flowering). In sorghum the peak nitrate reductase (NR) activity was recorded at 60 DAS while in soybean it was at 30 DAS. The NR activity was higher in intercrop sorghum than that in sole sorghum. Maximum NR activity was observed in 100% NPK. Soybean/sorghum intercropping system recorded significantly higher root and shoot biomass than sole soybean and sorghum. The crop growth rates were relatively rapid during 30-60 DAS and followed the order; intercropping > sole sorghum > sole soybean. With the increase in NPK dose from 0% to 100% there was significant improvement in the dry matter (DM) production in sole sorghum and soybean/sorghum intercropping system. Soybean as preceding crop recorded the highest DM, chlorophyll content, NR activity in wheat while these values were the lowest in sorghum-wheat system.     

Copper nutrition of Eucalyptus maculata Hook. seedlings: Requirements for growth,distribution of copper and the diagnosis of copper deficiency

A glasshouse experiment was conducted to define the response of Eucalyptus maculata seedlings to the addition of nine rates of copper (Cu) to a Cu-deficient sand. Plants were harvested 128 days from sowing. Symptoms of Cu deficiency included marginal necrosis in young fully expanded leaves (YFEL), deformed leaf margins, death of lateral shoots, bleeding at nodes on the main stem and reduced lignification of xylem fibres and vessels. Plant height and the number of nodes on the main stem were unaffected. In plants supplied with 0 Cu, whole top and root fresh weights were depressed by 27% and 32% respectively. The external Cu requirement for maximum growth of E. maculata seedlings was similar to that for wheat grown in the same soil. In Cu-adequate plants, leaf Cu concentrations decreased with distance from the shoot apex. Cu levels in stems varied little with position and were similar to the YFEL. Cu concentrations in leaves and stems were depressed in Cu-deficient plants to <1.0 g g^–1 dry weight (d.w.) (roots: 1.5 g g^–1 d.w.). The external Cu supply did not greatly alter the distribution of Cu within the plant. Young leaves at the shoot tip are recommended for diagnosis of Cu deficiency: critical values for shoot d.w. were about 1.5 g Cu g^–1 d.w. Lignification of wood was suppressed where Cu concentrations fell below 1.5 g g^–1 d.w.: the Bussler test for lignification would thus be a valuable indicator of Cu deficiency.