氮素形态配比对莴笋品质和养分含量的影响

采用营养液培养方法研究氮素形态配比对莴笋产量和品质及养分含量的影响。结果表明:不同处理降低莴笋产量4.5%～13.2%,降低莴笋根重29.8%～48.2%,处理6除外;处理2和处理3莴笋VC含量提高15.6%～16.2%,,处理2增加莴笋可溶性糖含量14.0%,处理4降低莴笋氨基酸含量24.0%;不同氮素形态配比处理均降低莴笋硝酸盐含量达7.5%～42.0%,降低营养中硝态氮比例,增加铵态氮或者酰胺态氮比例提高莴笋全氮含量,对全磷和全钾含量影响不一致。综合分析表明,处理2（NH₄⁺:NO₃^-=2（Cl）:8）为最佳处理。     

增施铵态氮对北方冬季基质栽培普通白菜根系特性及养分利用的影响

为了探究我国北方地区冬季叶菜类蔬菜基质栽培中N素的高效利用模式,以普通白菜为试材进行盆栽试验,以全量硝态氮供应(N素供应量17.33 mmol·L~(-1))为对照,设置25%、40%、60%3个增铵水平,观测普通白菜生长过程中根系的生长、活力以及N素代谢关键酶活性,测定其养分吸收、产量及品质。结果表明:增铵25%～40%能够提高普通白菜根系总长、根表面积和体积,促进根系发育,提高其对N、P素的吸收;相对全硝态氮素供应,增铵能够显著降低普通白菜硝酸盐含量,显著提高可溶性糖含量,但对单株质量无显著影响;增铵40%处理的氮肥偏生产力比增铵25%、60%处理分别提高了3.7%和3.8%,并显著提高了普通白菜地上部干物质量。综上,北方冬季设施栽培普通白菜,以硝态氮(17.33 mmol·L~(-1))为主配增施40%铵态氮的效果最好。     

氮素浓度及形态对韭菜硝酸盐及硝酸还原酶活性的影响

水培条件下,研究了氮素浓度及氮素形态对"汉中冬韭"体内硝酸盐含量和硝酸还原酶活性的影响。结果表明:随营养液供氮浓度的提高,韭菜叶片硝酸盐含量及硝酸还原酶活性均呈上升趋势;随营养液中铵态氮浓度的增加,韭菜叶片的硝酸盐含量及硝酸还原酶活性均逐渐降低;以硝酸盐作为衡量标准,韭菜适宜的氮肥施用量为4～8 mmol/L,适宜的NO₃^-←NH₄⁺为1←3～0←4。     

不同铵硝配比对辣椒产量、养分积累和氮肥利用率的影响

通过设施大棚辣椒盆栽试验,设置不施氮肥(CK)、铵态氮与硝态氮的氮质量比分别为0:100(A0N100)、25:75(A25N75)、50:50(A50N50)、100:0(A100N0)5个处理,研究不同铵硝态氮配比对辣椒产量、养分积累和氮肥利用率的影响.结果表明,与CK相比,不同铵硝配比处理增加了辣椒的果实数、鲜果...     

不同氮素形态对黄瓜根区土壤微生物数量及土壤酶活性的影响

采用苗期盆栽试验,研究了不同氮素形态配比对黄瓜幼苗根区土壤微生物数量及土壤酶活性的影响。研究涉及N1（NH₄⁺-N∶NO₃^--N 为10∶0）、N2（NH₄⁺-N∶NO₃^--N 为7∶3）、N3（ NH₄⁺-N∶NO₃^--N 为5∶5）、N4（NH^₄+-N∶NO₃^--N 为3∶7）共4 个氮肥配比处理,以施入同体积清水为对照。结果表明：施氮处理的黄瓜幼苗植株鲜质量、干质量均高于CK,其中N3 处理明显高于N1、N2 及CK;N3、N4 处理的黄瓜根区土壤微生物总数较高,其中土壤细菌、放线菌数量明显高于
N1 和CK,真菌数量则低于其他处理;土壤脲酶、中性磷酸酶活性均以N2 处理最高,N3 处理的土壤脱氢酶活性显著高于其他处理,施氮处理的过氧化氢酶活性均显著低于CK。结论：施加氮肥可以提高黄瓜植株鲜质量、干质量、土壤微生物数量和土壤酶活性。硝态氮肥比例的增加能够提高黄瓜植株鲜质量、干质量及土壤细菌、放线菌数量和土壤脱氢酶活性,而铵氮肥比例的增加可以提高土壤真菌数量和土壤脲酶、中性磷酸酶活性。综合评价,设施黄瓜栽培以N3 处理效果最佳,即
NH₄⁺-N∶NO₃^--N 为5∶5。     

豆梨铵转运蛋白基因PcAMT1-1 和PcAMT1-2 的克隆与功能鉴定

 为探明豆梨（Pyrus calleryana Dcne.）铵转运蛋白基因家族成员的序列特征、生理功能和表达特点，以豆梨幼苗为材料，运用电子克隆与3′-RACE 技术获得2 个铵转运蛋白基因PcAMT1-1 和PcAMT1-2，采用酵母互补和半定量RT-PCR 方法研究它们的生理功能与表达特点。结果表明：PcAMT1-1和PcAMT1-2 开放阅读框为1 518 bp 和1 515 bp，编码的蛋白分别含505 和504 个氨基酸残基。PcAMT1-1和PcAMT1-2 分别与甜橙 × 枳后代CpAMT（ABI52423）和茶CsAMT1;2（AB114913）的同源性最高（81.96%和78.31%）。PcAMT1-1 和PcAMT1-2 转入酵母均能使铵转运体缺失突变菌株31019b 恢复NH₄⁺吸收能力，在酸性条件下（pH 4.8 或5.8）PcAMT1-1 和PcAMT1-2 对31019b 的互补效果均优于中性条件（pH 6.8）。NH₄⁺有毒类似物MeA+可以显著抑制转PcAMT1-1 酵母31019b 的生长，该物质对转PcAMT1-2酵母31019b 无抑制效果；谷氨酰胺合成酶抑制剂MSX 可有效抑制PcAMT1-2 对酵母31019b 的互补效果，对PcAMT1-1 的互补效果无显著影响。正常供铵，PcAMT1-1 主要在叶中表达，PcAMT1-2 主要在根中表达；无氮处理后，PcAMT1-1 和PcAMT1-2 在根中的表达先上调后下降；重新供铵后，它们的表达量恢复；地上部的表达对上述处理无显著响应。综上所述，PcAMT1-1 和PcAMT1-2 在豆梨中具有吸收或转运NH₄⁺的功能，并可能具备不同的调控机制。     

氮肥形态及配比对铁核桃根际环境及幼苗生长的影响

 为了探索不同形态及配比的氮肥对铁核桃（Juglans sigillata Dode.）根际生态因子的影响, 为施肥提供科学依据,采用土壤盆栽试验方法,以铵态氮（NH4 +-N）、硝态氮（NO3 --N）和酰胺态氮[CO(NH2)2] 为氮源,研究氮肥形态及配比对实生苗生长和根际土壤中低分子量有机酸含量、微生物数量及多种酶活 性的影响。结果表明：混施等比例NH4 +-N 和NO3 --N 的实生苗株高、基径、植株的鲜质量及地上部和根 系的鲜质量都最大（P < 0.05）,分别为58.03 cm、18.21 mm、238.19 g、147.68 g 和90.51 g,根际土壤中 有机酸总量和细菌、真菌、放线菌的数量及微生物多样性指数显著高于其它处理,分别为16.72 μg · g-1 FW、 592.00 × 105 CFU · g-1、34.33 × 104 CFU · g-1、19.33 × 105 CFU · g-1 和0.1738;酸性磷酸酶、中性磷酸酶、 碱性磷酸酶、蔗糖酶和淀粉酶的活性最强（P < 0.05）,分别为9.54、0.24、3.60、61.98 和8.03 mg · g-1。 单一施CO(NH2)2、NO3 --N、NH4 +-N 会降低根际土壤中有机酸含量、微生物数量和微生物多样性指数。在 混施NH4 +-N 和NO3 --N 的情况下增加NO3 --N 比例会明显降低根际土壤蛋白酶活性。根际土壤中细菌、真 菌和放线菌的数量与中性磷酸酶、碱性磷酸酶、硝酸还原酶、蔗糖酶和淀粉酶活性呈显著或极显著正相 关;细菌数量与酸性磷酸酶活性呈显著正相关;有机酸总量与脲酶、中性磷酸酶、碱性磷酸酶、硝酸还 原酶、蔗糖酶和淀粉酶的活性及微生物数量呈显著或极显著正相关;微生物数量及有机酸总量与过氧化 氢酶呈极显著负相关。混施等比例的NH4 +-N 和NO3 --N 能够改善铁核桃根际生态环境,促进实生苗的生 长。     

Controlling the growth and development of rose plants after planting

The effects of pinching and lateral bud removal (deshooting) on the development of structural shoots, the number of flowers, and the average flower stem length in young rose plants were examined, using the cultivars ‘Baccara’, ‘Sonia’ and ‘Belinda’. The effect of deshooting on flower yield varied with each cultivar. It did not affect the number of ‘Baccara’ flowers, but increased ‘Sonia’ and ‘Belinda’ flower production by 50% and 75%, respectively. Leaving flowers to bloom out on plants before the start of commercial harvest resulted in a decrease in the length of the flower stems and also reduced the beneficial effect of deshooting on flower yield. Deshooting enhanced structural shoot formation (“bottom breaks”). Pinching flower buds of structural shoots increased the number of ‘Baccara’ flowers in comparison with pruning these shoots to 40–60 cm, as in common practice. Deshooting of the structural shoots of ‘Sonia’ and ‘Belinda’ increased the number of flowers in both cultivars.     

Flowering influences adventitious root formation in chrysanthemum cuttings

Root formation in chrysanthemum (Dendranthemum grandiflora (Ramat.) Kitamura) cuttings was reduced as flowers developed on stock plants. This effect was shown for all ten cultivars evaluated in this study. Not all cultivars were affected equally by the presence of flower buds on cuttings. There was no relationship (r² = 0.06) between root formation in vegetative cuttings and the ability for a cultivar to root from flowering cuttings. IBA (1 mM) could partially overcome the negative effect of flowering on root formation, but cuttings taken after the flower buds had fully opened failed to root even after auxin treatment. Removing buds from cuttings or continually removing flower buds during stock plant growth reduced rooting compared to cuttings with flower buds intact. Furthermore, cuttings taken from the top three nodes of the stock plant containing flower buds rooted comparably to cuttings taken from the lower stem section that contained only vegetative buds. The negative influence of flowering on root formation appears to be due to the photoperiodic induction of the flowering stimulus rather than a direct competition for resources between flowers and developing roots.     

生长调节剂对麻疯树成花及营养物质的影响

运用正交实验设计,用不同水平的6-苄氨基嘌呤（6-BA）+赤霉素（GA₃）+肥种处理麻疯树茎尖,研究外源物质对麻疯树花芽分化及树体内营养物质的影响。结果表明:各处理对麻疯树成花数量有显著影响,6-BA（2 mg/L）+GA₃（50 mg/L）+肥种（氮）为最优促花组合,正交实验设计中以6-BA（0.5 mg/L）+GA₃（50 mg/L）+肥种（氮）的促花效果较好;GA₃是影响麻疯树成花的主要因子。处理促进营养生长和生殖生长,二者交错进行。处理株叶片内氮、可溶性糖、淀粉、C/N比、钾的含量和变化趋势均呈增加-降低-再增加的S型模式。磷的含量在早期达到最大,之后便持续下降。叶片内钾在最高含量是最低含量的4.8倍,变幅最大,磷和钾呈极显著正相关。枝条生长与叶片内可溶性糖含量显著负相关。     

4 种熏蒸剂对土壤硝化作用及相关酶活性的影响

以北京市顺义区黄瓜、番茄轮作3 a 以上的温室土壤为对象,采用室内恒温通气培养法,研究氯化苦（Pic）、1,3- 二氯丙烯（1,3-D）、二甲基二硫（DMDS）和威百亩（MS）等4 种熏蒸剂对土壤硝化作用和几种相关酶活性的影响,并对Pic 处理中可能影响硝氮含量变化的一些指标进行了相关性分析。结果表明：4 种熏蒸剂处理均对土壤硝化作用有明显抑制作用,其中Pic、1,3-D 和MS 处理对土壤硝化作用的抑制持续28～56 d,而DMDS 的抑制作用只有7 d 左右;Pic 对土壤蛋白酶活性表现出显著的增强作用,而MS 则对蛋白酶活性有强烈的抑制作用;各熏蒸剂处理对土壤谷氨酰胺酶和天冬酰胺酶均表现出不同程度的抑制作用。Pic 处理土壤硝氮（NO^₃--N）与铵氮（NH^₄+-N）、可溶性有机氮（DON）的相关系数分别为-0.977 和0.887,均达极显著水平;与可溶性氨基酸（DAA）和土壤微生物量氮（SMBN）相关系数分别为-0.628 和-0.645,均达显著水平。     

AgNO_3不同处理时期和浓度对西葫芦性别表现和花粉活力的影响

为筛选出诱导西葫芦雄花的最佳时期和AgNO3浓度,于3个不同的生长时期,用3种不同浓度(300,400,500 mg/L)的AgNO3处理西葫芦幼苗。试验结果表明,在不同时期用AgNO3可提高西葫芦第一雄花节位,增加2花芽/叶腋数,减少雌花数,且处理时间越早,第一雄花节位越高,雌花数越多;同一处理时期,随着AgNO3浓度的增加,雌花数减少,2花芽/叶腋数增加,子叶平展期和1叶1心期用400 mg/L AgNO3处理西葫芦幼苗,雄花数最多,花粉活力最高;仅1叶1心期和2叶1心期可诱导两性花产生,且随着处理时间的推迟和AgNO3浓度的增加,两性花越多,植株长势减弱。研究结果表明,子叶平展期用400 mg/L AgNO3处理西葫芦幼苗,诱雄效果最佳。     

Dexamethason enhanced aorta-derived CD105+ mesenchymal stem cells to differentiate into adipocytes

AIM: To investigate whether aorta-derived CD₁₀₅⁺ cells show characteristics of mesenchymal stem cells, and if dexamethason enhances this kind of CD₁₀₅⁺ cells to differentiate into adipocytes. METHODS: The distribution of CD105 in aorta was assessed by imunohistochemistry. The aorta wall cells were isolated and immunophenotypes were identified by FACS. CD₁₀₅⁺ cells were sorted using MACS CD105 micromagnetic beads. The differentiation of CD₁₀₅⁺ cells into adipocytes and osteoblasts was induced under different conditions and indicated by staining of Oil red O, detecting of alkaline phosphatase activity, calcium accumulation stained with silver nitrate and transmission electron microscope analysis, respectively. RESULTS: The endothelial cells, a part of medial smooth muscle cells and adventital fibrblasts were CD105 positive. The isolated aortic arch cells were positive for CD105, CD106, CD44, CD29, and negative for CD45, CD11a, CD11b and HLADR. The CD₁₀₅⁺ cells differentiated into adipocytes contained Oil-Red-O-positive lipid droplets, the osteocytes with calcium deposition and alkaline phosphatase activity. Ultrastructurally, it was observed that some needle-shaped crystal calcium deposition similar to bone spicules was inside the cytoplasm of induced osteocytes. When the dexamethason was absent in the adipogenic medium, there were no adipocytes with lipid droplets. CONCLUSION: The results demonstrated that CD₁₀₅⁺ cells showed characters of MSCs reside in aortic wall, and was able to differentiate into adipocytes and osteocytes in vitro. Dexamethason enhanced aorta-derived CD₁₀₅⁺ with characters of MSCs to differentiate into adipocytes. These suggested that MSCs might be related with atherosclerosis.     

Effect of maleic hydrazide on endogenous cytokinin contents in lateral buds,and its possible role in flower bud formation on the Japanese pear shoot

In order to elucidate the role of maleic hydrazide (MH, 1,2-dihydro-3,6-pyridazinedione; coline salt) in increasing flower bud formation on the Japanese pear, the effect of MH on cytokinin contents in the lateral buds of Japanese pear shoots were investigated. Foliar application of MH at 2600 mg l⁻¹ increased zeatin, zeatinriboside, and isopentenyladenine levels in lateral buds though isopentenyladenosine concentration decreased. Application of 2,3,5-triiodobenzoic acid (TIBA), an inhibitor of polar auxin transport, also increased the endogenous cytokinin levels in lateral buds. It is supposed that these increases of cytokinin in lateral buds may be involved in the increase of flower bud production on the Japanese pear shoot. The increases of cytokinin induced by these chemicals may be caused via the depletion of the auxin level and/or the activity in shoot tissues.     

In vitro propagation of Symphytum species

Methods are described for the in vitro propagation of Symphytum × uplandicum Nyman from bud, root and stem explants. Highest shoot numbers were produced from root explants > 4 mm in diameter, cultured vertically with their distal cut surface on the medium. The most suitable medium for shoot production was Murashige and Skoog's (MS) with 0.3 mg l⁻¹ 6-benzylaminopurine (BAP). These shoots developed roots on MS medium without hormones and were successfully transplanted into pots. Subculturing shoots onto MS medium containing BAP, kinetin (K), 6-λ,λ-(dimethylallylamino)-purine or gibberellic acid (GA₃) at 0.5, 1.0, 5.0, 10.0 or 30.0 mg l⁻¹ failed to stimulate outgrowth of axillary buds in culture. In vitro propagation from root explants was also achieved with S. asperum Lepech., S. officinale L. and S. × uplandicum cultivars ‘Bocking 1’, ‘Bocking 2’, ‘Bocking 4’ and ‘Bocking 17’, but not with S. bohemicum, S. grandiflorum DC, S. tuberosum L. or S. × uplandicum ‘Bocking 7’ and ‘Variegatum’.     

茶树亚硝酸还原酶基因CsNiR的克隆及表达分析

以‘龙井43’茶树叶片的cDNA为模板,利用RT?PCR技术克隆了茶树亚硝酸还原酶基因（CsNiR）,得到完整的ORF全长为1 764 bp,编码587个氨基酸;所推导的氨基酸序列与垂枝桦（Betula pendula）、拟南芥（Arabidopsis thaliana）、菠菜（Spinacia oleracea）和水稻（Oryza sativa）的同源性均大于76%。生物信息学分析表明,CsNiR分子量为68.648 kD,等电点为6.12,为亲水性的非分泌蛋白;二级结构的预测显示,CsNiR具有完整的NiR 蛋白结构,含血红素蛋白β–化合物区域和4Fe-4S区域。实时荧光定量结果表明,该基因在成熟叶片中表达量高于一芽二叶和根。采用营养液水培3个茶树品种,在氮饥饿两周后分别供应正常氮素和低氮素（1和0.1 mmol · L^-1 NH₄NO₃）,qRT-PCR测定发现,正常氮素处理的2 h和6 h,诱导根CsNiR表达量显著增加,叶片中的表达量变化延迟到24 h之后,且变化幅度存在基因型之间的差异;低氮处理对CsNiR表达量的影响相对较小。因此,研究CsNiR基因的表达特性及其在茶树氮素利用中所发挥的作用,需结合茶树基因型、组织部位、供氮水平等进行综合评价。     

Apical Dominance and Flower Initiation in the Rose

The initiation of leaves and flowers by selected axillary buds of the glasshouse rose cultivar Sonia (syn. Sweet Promise) has been studied both while their extension growth was inhibited by apical dominance and after the inhibition had been removed at one of two times (“early” or “late”). Leaf initiation occurred during growth inhibition so that leaf primordia accumulated in the axillary buds. Flower initiation began, with both treatment times, only after removing apical dominance. Although the total number of leaf primordia formed before the flower was greater in plants of the “late” treatment, the axillary shoots produced in both treatments had similar numbers of leaves with expanded leaflets. Thus many leaf primordia of the “late” treatment plants became scales. The evidence suggests that flower initiation cannot begin while an axillary bud is subject to apical dominance, and that after its removal another factor results in the production of shoots with a relatively constant number of leaves with expanded leaflets.     

The responses of early-flowering chrysanthemums to daylength

In a study of photoperiod response 30 early (summer)-flowering chrysanthemum cultivars from Britain and Japan reacted as quantitative short-day plants. Both flower bud initiation and development occurred more rapidly in short days (SD) as compared with long days (LD). The early-flowering cultivars differed from late-flowering chrysanthemums in that lateral flower buds, and often the terminal flower buds, develop to anthesis in LD. Internodes were shorter in SD and flowers had fewer florets. There was an increased number and proportion of disc florets in SD in all cultivars except one. Two cultivars, ‘Mezame’ and ‘Pennine Yellow’, closely approached day-neutrality.All cultivars produced fewer leaves in LD on upper lateral shoots than on main stems. Either the presence of the terminal flower bud induces earlier flowering of the upper lateral shoots, or the change which causes the terminal apical meristem to initiate a flower in LD influences the axillary meristem also.SD could be used to speed up the flowering of glasshouse-grown crops of early-flowering cultivars. The advantages and disadvantages which may be associated with treatment at different stages of growth are discussed.     

Study on changes of ET、NO level and tumor weight of mice bearing S180 model and their relationships

AIM: To approach the changes of ET and NO levels of mice bearing sarcoma 180 (S₁₈₀ ) during different period(5、10 and 15 days) and the relationship between ET、NO and tumor’s development METHODS: Adopting mice bearing S₁₈₀ as the models, the levels of ET and NO₂^-/NO₃^- in serum were detected, and the weight of isolated tumors was measured On the basis of the regulation of these changes, their relationships were explored RESULTS: The levels of ET and NO₂^-/NO₃^- of mice bearing S₁₈₀ were higher than that of the control group (not bearing tumor) ( P< 0.05) Along with the development of the tumors, the levels of NO₂^-/NO₃^-and tumors weight both increased ( P< 0 05) ET also had an increasing tendency There was a positive correlation between the level of NO₂^-/NO₃^- and tumor weight ( r =0.995, P< 0.05) Ratio value of (NO₂^-/NO₃^-)/ET decreased at first and then increased CONCLUSION: ET and NO have links with the development of S₁₈₀ There may be cooperation between ET and NO during the development of tumor.     

杨桃新梢花芽分化及其碳水化合物含量的变化

 以6年生盆栽甜杨桃为材料，观察了新梢上各节位芽的分化情况，比较了新梢上不同节位的碳水化合物含量。结果表明：当第2节位开始“露红”（肉眼可辨红色的花芽）时，新梢上各节位上的芽（顶芽除外）基本上进入形态分化阶段。第3和第4节位“露红”的枝条，韧皮部和木质部可溶性糖含量比第1位和第2位“露红”的枝条高。徒长枝第1节位的可溶性糖和淀粉含量都较高，第3、第5节位的含量与第1或第2节位“露红”的成花枝上相应节位的含量相当。本研究结果表明，杨桃新梢上的芽在进行形态分化的过程中，枝条仍在积累碳水化合物。