紫苏种子发芽检验标准化研究

研究了温度、光照及发芽床等因素对紫苏种子萌发的影响。试验结果表明,紫苏种子发芽最适温度为恒温20℃,发芽床可选择纸上或砂上;紫苏种子萌发对光照不敏感,在光照或黑暗条件下均可发芽,发芽时初次计数时间为发芽后第3天,末次计数时间为发芽后第8天。     

三种豆科植物种子萌发特性的研究

通过温度、光照、浸种时间及发芽床对3种豆科植物种子萌发影响的研究.结果表明:绿豆种子萌发温度以15～25℃为最佳;阴暗条件比光照条件下萌发速度更快;浸种6～10 d可极显著地提高发芽数;发芽床以纸上和纸间为最佳.大豆种子萌发温度以20℃为最佳;阴暗条件比光照条件下萌发速度更快;浸种6 d可显著地提高发芽数;发芽床以黄壤土为最佳.豇豆种子萌发温度以15℃为最佳;浸种2～3 d可显著地提高发芽数,阴暗条件比光照条件下萌发速度更快,发芽床以黄壤土为最佳.     

求米草种子萌发特性研究

对求米草种子萌发条件进行了研究,结果表明:求米草种子最佳的浸种时间是12～24 h;萌发最适的温度条件为20～25℃;光照对种子萌发的影响不大;草炭 珍珠岩(1:1)及草炭最利于种子萌发.     

野生藏药独一味种子萌发特性初步研究

通过对种子进行光照、温度、浸种时间和赤霉素处理,统计其发芽率、发芽势、发芽指数和胚根长度.结果表明:在光照条件下,15、20、25℃时种子的发芽率分别为83.33%、82.67%、80.67%,25℃时发芽势最高为68%,发芽指数最大为7.92,胚根最长为1.24 cm;在光照条件下15、20、25、30、35℃的发芽率均显著高于黑暗;浸种24 h发芽率最高;经50、200、350、500 mg/L的赤霉素处理的种子萌发各指标都低于对照(蒸馏水).初步探明,独一味种子无休眠现象;适宜萌发条件为光照下,温度20~25℃,属中温萌发型,高温40℃和低温10℃对种子萌发有抑制作用.     

几种处理对两种白头翁种子萌发的影响

以白头翁和兴安白头翁种子为试材,研究了植物生长激素、温度、光照和浸种等处理方法对2种白头翁种子萌发的影响.结果表明:5 mg/L NAA和100 mg/L GA3处理的白头翁种子萌发率显著高于对照(P＜0.05);10和50 mg/L GA处理的兴安白头翁其发芽率和发芽势均显著高于对照(P＜0.05).2种白头翁种子的萌发率和发芽势均随着温度的升高而明显增高,适宜的发芽温度为25～30℃.延长光照和浸种时间处理可以明显促进2种白头翁种子的萌发率和发芽势.     

白花前胡种子发芽试验研究

以源于安徽的白花前胡种子为试材,研究了浸种时间、发芽温度、不同发芽床、不同光照条件对白花前胡种子发芽的影响。结果表明:浸种可以促进白花前胡种子的萌发,浸种时间以18h为宜。白花前胡种子适宜的发芽温度为20℃;适宜的发芽床为粗砂床;光照条件为光照12h/黑暗12h为宜;发芽试验的初次计数时间为第7天,末次计数时间为第20天。试验初步确定了白花前胡种子的发芽技术标准及幼苗鉴定技术,为白花前胡种子检验提供了参考依据。     

景天三七种子萌发特性研究

以景天三七(Sedum aizoon)种子为试材,研究了光照、温度及不同发芽床条件等3个因素对景天三七种子萌发的影响。结果表明:景天三七种子萌发对光照不敏感,为光中性种子;温度是影响其种子萌发的重要生态因子,综合发芽率、发芽势、发芽指数得出其萌发最适温度为25℃,发芽率为92.8%。滤纸床和土床培养条件下,景天三七发芽率没有显著差异。但与滤纸床相比,土床可以显著提高其种子发芽速率和发芽整齐度。该研究结果对于了解景天三七种子萌发特性,指导其工厂化育苗提供了理论依据。     

芹菜高产栽培技术

1 芹菜生长特性与栽培技术措施 芹菜生长的适应性强,喜凉性环境,为半耐寒蔬菜.芹菜生长适温范围广,可耐受短时低温.种子发芽温度最低4℃,适宜均温15～20℃,一般温度15℃以下种子萌发慢,达30℃种子不萌发. 芹菜生长之初能耐受-5～-7℃.温度12～13℃芹菜可完成春化,时间周期10～30天.     

消毒时间、光照和温度对金鱼草种子萌发的影响

以金鱼草种子为研究对象,研究了用质量分数2%NaClO消毒不同时间、不同温度、变温、光照和黑暗处理对种子萌发的影响。结果表明:用2%NaClO消毒6min为金鱼草种子适宜的消毒时间。黑暗处理使幼苗徒长,光照条件下植株生长健壮,黑暗和光照处理对种子萌发率影响不大。金鱼草种子在25℃时发芽率最高,为88.89%。种变温30℃/20℃处理加快了种子的萌发,整体提高了种子发芽率。     

黄花月见草种子发芽特性的研究

研究了不同温度、光照、贮藏条件对黄花月见草种子发芽特性的影响。结果表明:黄花月见草种子在152、02、5和30℃恒温条件下均可萌发,发芽率接近60%,15/25℃变温下发芽率较高,达98%。光照对种子萌发影响不大,可以推测黄花月见草种子为非光敏型种子。贮藏期也是影响种子发芽率的另一因素。保存24个月的种子发芽率超过50%,从发芽势考虑,贮藏期不超过15个月的种子更利于齐苗。     

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.