三种观赏植物水培营养液配方初步研究

采用不同配方的营养液对彩叶凤梨、小叶榕和天竺葵进行了水培试验.结果表明:3 种植物对不同配方营养液有不同的适应性,大量元素为11.5 mg/L(以下单位同)NH4 -N 140.2 NO3--N 93.0 P 312.0 P 80.0 Ca 18.3 Mg 45.0 S的营养液(pH 6.12,EC 为1.32 ms/cm)较适合彩叶凤梨和小叶榕的生长,而天竺葵在大量元素为21.0 NH4 -N 137.2NO3--N 44.5 P 265.2 K 92.0 Ca 36.0 Mg 48.0 S的营养液(pH5.60,EC 为 1.35 ms/cm)中生长最好.     

银川地区水质的非洲菊沙培营养液配方筛选研究

应用三元二次通用旋转组合设计,采用沙培方法,在二代节能日光温室内研究了营养液配方中的NO₃-N、P、K的摩尔浓度对非洲菊产量的影响。结果表明:3个元素对非洲菊产量的影响大小顺序是:氮>磷>钾;通过计算机模拟寻优,非洲菊单株最高产量8.65枝/株时,NO₃-N、P、K 3个因子营养液的最优配方为:12、1.5、4mmol/L。     

设施黄瓜砂培营养液配方筛选试验

采用三因素五水平通用旋转组合设计,在现代日光温室内研究了营养液配方中不同摩尔浓度的NO3--N、P、K对黄瓜产量的影响,得到了三者之间的回归方程,依此进行分析。结果表明:3个元素对黄瓜产量的影响大小顺序是:氮磷钾;通过计算机模拟寻优,黄瓜达到单株最高产量1 395.97 g时,营养液中NO3--N、P、K最优配方为:15、1.0和6.0 mmol/L。经过验证,最优配方处理A、B的株高、茎粗、生长势、产量、品质表现相对优于对照。     

不同氮形态对沙培黄瓜幼苗生长及养分吸收的影响

以黑龙江主栽黄瓜品种"津春3号"为试材,采用盆钵培养的方法,研究了营养液中不同NO3--N与NH4+-N配比对黄瓜幼苗生长及氮、磷养分吸收的影响。结果表明:沙培条件下,营养液中氮的总浓度为15mmoL/L时,随着营养液中NH4+比例的增加,幼苗长势随之变弱;全NO3--N处理的幼苗叶面积、干重及壮苗指数分别是全NH4+-N处理的1.92、2.12与3.07倍;氮形态对幼苗地上部全氮含量与硝酸还原酶活性无显著影响,而对幼苗地上部全磷含量影响显著,全NO3--N处理的幼苗磷含量显著高于全NH4+-N处理,为全NH4+-N处理的2倍;受NH3毒害,全NH4+-N处理的幼苗根系活力显著下降,地上部游离氨基酸含量显著上升。全NO3-处理对黄瓜幼苗生长最有利。     

水培生菜氮磷钾产量模型的构建与分析

为定量揭示水培生菜产量对营养液主要营养元素氮磷钾浓度的关系,以香港"玻璃脆"散叶生菜为试材,设置不同氮磷钾营养液配方,采用三因素(N、P、K)五水平二次通用旋转组合设计试验,分析了水培生菜在前、后期氮磷钾对产量的影响,建立了生菜产量对三因素的回归数学模型。结果表明:前期三因素对产量的影响顺序是NKP,后期为NPK;各因素间存在着交互作用,营养液中氮离子浓度和钾离子浓度均呈正相关,磷离子与钾离子浓度均呈负相关;在生长前期,当氮磷钾浓度分别为8.46、0.62、2.57mmol·L~(-1)时,产量最高为12.26g·株~(-1);在生长后期,当氮磷钾浓度分别为4.65、0.69、2.43mmol·L~(-1)时,产量最大为88.27g·株~(-1)。     

不同浓度营养液对蕹菜生长的影响

本试验采用不同营养液对蕹菜的株高、叶量生长状况的研究,探索蕹菜生长发育的最佳营养液配方。结果表明:在一定的浓度范围内营养液中的大量元素浓度高(配方2),缩短蕹菜的生长周期;在一定的浓度范围内营养液中大量元素的浓度低(配方4),延长蕹菜的生长周期。结论:营养液中的大量元素对蕹菜生长有利;在蕹菜无土栽培中营养液的大量元素含量在配方2的浓度蕹菜生长最好。     

不同氮磷钾配比对仙客来生长的影响

对仙客来无土栽培营养液中N、P、K元素采用三因素二次D-饱和最优设计,探讨不同浓度氮磷钾对仙客来生长发育的影响,对仙客来的根长、根体积、球茎直径、花朵数、花瓣长、可溶性糖含量、MDA含量、蛋白质含量、叶绿素含量进行分析。结果表明:经方差分析和主成分分析得出,无土栽培仙客来氮、磷、钾最优组合方案为:86.6~263.4、60~100和250~400 mg/L,即氮:磷:钾为3∶1∶6.5。     

氮磷钾化肥配施对花生产量的影响

在测定土壤肥力的基础上，选定邹城市花生地进行效应函数法配方试验，以找出不同N、P、K用量与花生产量的关系，明确最高施肥量和最佳施肥量，提供花生专用配方肥参数。试验发现氮、磷、钾配合施用仍是花生取得高产的有效措施。氮、磷、钾化肥对花生产量的影响程度为：P〉N〉K。建议供试土壤的施肥配方为：N：P2O5：K2O=1：0．5～0．6：0．4～0．5．     

不同施肥水平对连葱9号产量的影响

采用四因素水平正交试验设计,研究了连葱9号高产栽培氮、磷、钾合理施肥技术参数。结果表明:施用单一元素的增产效果为NKP;多元素配合施肥增产效果为N+P+KN+PP+K;氮、钾二元素对连葱9号产量和品质影响大。在每667m2洋葱产量5000kg左右时,配方以N 25~30kg、P2O515~20kg、K2O 20~25kg为宜,增施有机肥应适当降低氮磷钾用量。     

优太功能肥对红富士产量及商品性的影响

作物生长需要16种营养元素,其中碳(C)来源于空气中的二氧化碳(CO2),氢(H)和氧(O)来源于大气降水,氮(N)、磷(P)、钾(K)称为大量元素;硼(B)、锰(Mn)、锌(Zn)、铜(Cu)、、钼(Mo)、铁(Fe)、氯(Cl)元素,作物需要量小,称作微量元素;钙(Ca)、镁(Mg)、硫(S)元素需要量介于中间,称中微量元素.除碳、氢、氧外,作物生长所需要的氮、磷、钾等矿质营养主要从土壤吸收获得,施肥是补充植物生长所需矿质营养的重要手段.根据土壤中各种矿质营养的含量和植物生长所需的矿质营养制订科学的配方,按配方施肥能明显的提高作物的产量和品质.     

Relationship between renal hypertension and cardiac α1-adrenoceptor autoantibodies in rats

AIM: To examine the autoantibody against α₁-adrenoceptor and its biologic activities during the development of renal hypertension. METHODS: Renal hypertension of rat was achieved by clipped renal artery, the titre of autoantibody to α₁-adrenoceptor was detected using ELISA immunoassay. Furthermore, the biological offects of these autoantibodies on cultured cardiomyocytes were also examined. RESULTS: After two weeks of clipping renal arteries, both the frequency of occurrence and the titre of autoantibodies to cardiac α₁-adrenergic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 12 weeks. The biological effects of these autoantibodies displayed an "agonistic-like" activities on the beating frequency of cultured neonatal cardiomyocytes. CONCLUSION: Autoantibodies against α₁-adrenoceptor may play a role in the elevation of peripheral vascular resistance and in the development of cardiac hypertrophy in rats with renal hypertension.     

Effects of radiation from 188Re on smooth muscle cell proliferation

AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β^-particles emission from ¹⁸⁸Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by ¹⁸⁸Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [³H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of ¹⁸⁸Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from ¹⁸⁸ Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G₀/G₁ arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation.     

Influence of Mineral Nutrients on Strawberry Fruit Quality and Their Accumulation in Plant Organs

Abstract

This review is based partly on complete articles and partly on abstracts. Three of the 60 articles deal with the total uptake of elements in strawberry plant organs in two different strawberry production systems, both considered as optimal concerning amount and balance of elements. The effect on fruit quality may be dramatic if the level of a particular element is outside this range, but there may also be effects initiated by differences within the optimal range of elements. Most articles refer to product oriented quality, but some focus on consumer oriented quality, as discussed by Shewfelt (1999). The discussion here is on a general basis, so one should keep in mind that there are cultivar differences and that specification of nutrition ideally should mirror the needs of a single cultivar, or a group of cultivars with similar requirements. Also, to get a complete understanding of the subject future reviews should embrace a broader access of information including the effect on plant development of individual elements, such as the role of calcium in fruit firmness and its importance in cell wall structure. However, the intention here is to narrow the information to results that suggest a direct connection between nutrient uptake and fruit quality.     

Effect of L-Arg on plasma content of endothelin and expression of c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy

AIM:To study the effect of L-Arg on plasma content of endothelin (ET) and the expression of proto-oncogene c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy. METHODS: The level of c-fos mRNA were measured by in situ hybridization. The ET in plasma were measured by radioimmunoassay. RESULTS:After eight weeks of treatment with L-Arg, the expression of c-fos decreased markedly (P＜0.01). The ET content in plasma also decreased significantly by L-Arg(P＜0.01).CONCLUSION: Plasma ET content and the expression of c-fos in the left ventricle of rats with renovascular hypertensive hypertrophy could be decreased by L-Arg administration.     

Mixed-severity fire regime in a high-elevation forest of Grand Canyon,Arizona, USA

Fire regime characteristics of high-elevation forests on the North Rim of the Grand Canyon, Arizona, were reconstructed from fire scar analysis, remote sensing, tree age, and forest structure measurements, a first attempt at detailed reconstruction of the transition from surface to stand-replacing fire patterns in the Southwest. Tree densities and fire-/non-fire-initiated groups were highly mixed over the landscape, so distinct fire-created stands could not be delineated from satellite imagery or the oldest available aerial photos. Surface fires were common from 1700 to 1879 in the 4,400 ha site, especially on S and W aspects. Fire dates frequently coincided with fire dates measured at study sites at lower elevation, suggesting that pre-1880 fire sizes may have been very large. Large fires, those scarring 25% or more of the sample trees, were relatively infrequent, averaging 31 years between burns. Four of the five major regional fire years occurred in the 1700s, followed by a 94-year gap until 1879. Fires typically occurred in significantly dry years (Palmer Drought Stress Index), with severe drought in major regional fire years. Currently the forest is predominantly spruce-fir, mixed conifer, and aspen. In contrast, dendroecological reconstruction of past forest structure showed that the forest in 1880 was very open, corresponding closely with historical (1910) accounts of severe fires leaving partially denuded landscapes. Age structure and species composition were used to classify sampling points into fire-initiated and non-fire-initiated groups. Tree groups on nearly 60% of the plots were fire-initiated; the oldest such groups appeared to have originated after severe fires in 1782 or 1785. In 1880, all fire-initiated groups were less than 100 years old and nearly 25% of the groups were less than 20 years old. Non-fire-initiated groups were significantly older (oldest 262 years in 1880), dominated by ponderosa pine, Douglas-fir, or white fir, and occurred preferentially on S and W slopes. The mixed-severity fire regime, transitioning from lower-elevation surface fires to mixed surface and stand-replacing fire at higher elevations, appeared not to have been stable over the temporal and spatial scales of this study. Information about historical fire regime and forest structure is valuable for managers but the information is probably less specific and stable for high-elevation forests than for low-elevation ponderosa pine forests.This revised version was published online in May 2005 with corrections to the Cover Date.     

Compositional and Functional Properties of Saskatoon Berry and Blueberry

Abstract

Saskatoon berry (Amelanchier alnifolia Nutt., Rosaceae) and blueberry (Vaccinium corymbosum L., Ericaceae) are substantially equivalent in all characteristics that are important to the consumer, including fruit color, shape, size, nutrition, texture, and uses. In addition, both fruits are native to North America and they have practically identical historical uses and known health benefits. Their composition, processing, nutritional value and metabolism, intended uses, and levels of undesirable substances are compared.     

Cryopreservation of shoot apices of hawthorn in vitro cultures originating from East Asia

The objective of this study was to establish a cryopreservation protocol for hawthorn shoot apices (Crataegus pinnatifida Bge.). Cryopreservation was carried out via encapsulation–dehydration, vitrification, and encapsulation–vitrification on shoot apices excised from in vitro cultures. We began by showing that cold-acclimation enhanced the regrowth of cryopreserved apices from 10.0 to 65.5% in encapsulation–dehydration. We then decided that the encapsulation–dehydration method was an optimal cryopreservation method for hawthorn shoot apices in terms of its high recovery after cryopreservation as well as its ease of use compared with vitrification and encapsulation–vitrification. In encapsulation–dehydration, the protocol leading to optimal regrowth was as follows: after cold-acclimation at 5 °C in the dark for 2 weeks, excised shoot tips were pretreated for 24 h at 25 °C on hormone-free Murashige and Skoog [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497] (MS) basal medium with 0.4 mol/L sucrose, then encapsulated and precultured in liquid MS medium with 0.8 mol/L sucrose for 16 h at 25 °C. Precultured beads were dehydrated for 6 h at 25 °C in the dessicator containing 50 g silica gel to a moisture content of 15.3% (fresh-weight basis) before cryostorage for 1 h. In addition, we examined the effect of adding glycerol to both the alginate beads and loading solution to enhance regrowth after cryopreservation in encapsulation–dehydration. In the present study, it was shown that adding 0.5 mol/L glycerol resulted in high regrowth percentages (82.5–90.0%) in four Crataegus species.     

瓜叶绿素降解关键酶基因PPH和PAO cDNA片段的克隆与表达初步分析

 以西双版纳黄瓜和‘华黄5号’黄瓜叶片为试验材料,研究了衰老过程中两种黄瓜叶片叶绿素含量变化及脱镁叶绿素脱镁叶绿酸水解酶基因PPH和脱镁叶绿酸a加氧酶基因PAO的表达。结果表明：随着叶片衰老,叶绿素a和叶绿素b含量显著降低,叶绿素a与叶绿素b的比值在0.5左右,推测叶绿素b的含量可能对黄瓜叶片保绿起到重要作用。荧光定量RT-PCR分析结果显示：PPH和PAO在西双版纳黄瓜叶片生长35 d时表达量最高,分别为5.50和1.86;PPH在‘华黄5号’叶片35 d时表达量最高,为7.14,而PAO在35和45 d表达量都很高,分别为3.90和3.91;PPH和PAO在西双版纳黄瓜叶片中的表达量低于在‘华黄5号’中。     

Effects of simvastatin on PDGF-BB and serum-induced proliferation of vascular smooth muscle cells and on the expression of tumor suppressor gene PTEN

AIM:To observe the effect of simvastatin on the proliferation of vascular smooth muscle cells(VSMCs) induced by serum and growth factor PDGF-BB and the effect of simvastatin on the expression of PTEN,a important regulator of G₁/S cell cycle transition. METHODS:The DNA synthesis was determined by [³H]-TdR incorporation, cell cycle was examined with flow cytometry, the protein level of PTEN was measured by Western blot method. RESULTS: (1)Simvastatin inhibited [³H]-TdR incorporation in a dose dependent manner. (2) Flow cytometric DNA analysis revealed that simvastatin induced significantly enhancement of G₀/G₁ phase and decrease in S phase VSMCs.(3)Simvastatin increased protein level of PTEN and mevalonate, a metabolite of HMG-COA, reversed the effect of simvastatin on PTEN protein expression. CONCLUSION:Simvastatin may inhibit proliferation of VSMCs and retarded cell cycle in G₀/G₁ phase by increasing PTEN expression through inhibiting synthesis of mevalonate.     

Relationships of landscape,prey and agronomic variables to the abundance of generalist predators in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) fields

A two-year field study investigated the possible effects of grain sorghum (Sorghum bicolor [L.] Moench) and uncultivated areas on the abundance of generalist predators in commercially-managed cotton (Gossypium hirsutum L.) fields in Texas, USA. From 63 to 70 fields were sampled for pests and predators over nine consecutive weeks during early stages of cotton development. Additional data on agronomic practices and landscape composition at three spatial scales were also collected for each field. Stepwise regression analyses were used to determine the relationships of landscape, agronomic and prey variables to the abundance of generalist predators. Because the variables most closely linked to predator levels could vary over time, separate regressions were conducted for three time periods corresponding to stages of grain sorghum growth (half-bloom, hard-dough, maturity) in each year. Significant relationships between predator abundance and agricultural landscape composition appear in both years and in all three time periods, but the specific relationships of landscape variables to cotton predator levels differed between and within years. At maturity in 2001, predator levels rose as the amount of uncultivated land from 1.6 to 3.2 km distant and the perimeter shared with grain sorghum increased. During 2002, the area of grain sorghum (half-bloom) and uncultivated land (hard-dough) within 1.6 km of cotton fields were both positively related to predator numbers. Cotton planting dates and the abundance of cotton fleahoppers (Pseudatomoscelis seriatus [Reuter]) were also strongly linked to predator numbers during both years. Results suggest that the total amount of grain sorghum or uncultivated land in an area is more important than the presence of these habitats adjacent to cotton fields, and that landscape composition may sometimes be the most important factor in determining predator abundance.