曲酸对鲜切马铃薯与莲藕的褐变及其相关酶活性的影响

以马铃薯(Solanum tuberosum)、莲藕(Nelumbo nucifera Gaertn)为试材,研究了0.1%、0.3%和0.5%曲酸处理鲜切马铃薯片及莲藕片在模拟货架期(4℃)的色泽及相关酶活性变化。结果表明,曲酸能不同程度地抑制马铃薯与莲藕的多酚氧化酶(PPO)、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)的活性。其中,0.3%和0.5%曲酸处理在保持鲜切马铃薯片及莲藕片色泽,抑制PPO,POD,PAL活性的效果好于未经处理的对照及1%柠檬酸的参比处理。未经处理的马铃薯片、莲藕片外观品质保持为5~6d或4~6d,0.3%和0.5%曲酸处理后的马铃薯片与莲藕片的货架期分别达10d或12d,1%柠檬酸的参比处理分别是8~10d或6~8d。     

委陵菜嫩茎再生体系建立的研究

[目的]建立委陵菜再生体系技术,保护野生资源,实现人工栽培.[方法]以委陵菜嫩茎为材料,用组织培养的方法,进行愈伤组织诱导与分化、试管苗生根、继代增殖、移栽定植的研究.[结果]愈伤组织诱导培养较适宜的培养基为:MS +40 g/L蔗糖+0.3 mg/L6-BA +2.8 mg/L 2,4-D;愈伤组织分化培养的合适培养基为:MS+ 35 g/L蔗糖+0.4 mg/L AgNO3 +0.1 mg/L NAA +0.8 mg/L ZT;不定芽生根培养的较适宜培养基为1/3MS+ 15 g/L蔗糖+0.5 mg,/L ABT+ 0.2 mg/L IBA+ 0.3 mg/L NAA.试管苗移栽成活率为95.1％,定植成活率为97.8％.[结论]建立的再生体系,1株试管苗1年能繁殖23万株试管苗,定植的试管苗保持了野生委陵菜的植物学性状.     

西双版纳黄瓜子叶原生质体培养

西双版纳黄瓜子叶在含1%纤维素酶、0.5%离析酶、加或不加0.3%半纤维素酶和0.3mol/L 甘露醇的CPW 酶液中游离出大量优质原生质体。浅层培养在附加0.5mg/L2.4-D 和1.0mg/L KT 等成份的KM_(8P)(-NH_4~+)培养基上,形成了微愈伤组织。转接到MS 附加多种成分的固体培养基上,愈伤组织得到增殖和生根。     

热处理对大葱茎尖脱毒效果的影响

利用章丘大葱茎尖进行脱毒效果研究。结果表明,当茎尖大小为0.15￣0.3mm或茎尖大小为0.3￣0.5mm,75℃高温处理10min后,脱毒率均达100%。细胞学观察结果表明,该途径能保持遗传稳定性。     

Seawater strontium isotopes, Acid rain, and the cretaceous-tertiary boundary

A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in seawater at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the seawater strontium isotope record at other times may reflect similar episodes.     

山新杨组织培养快繁技术研究

山新杨冬季枝条经FC处理,选择萌发新枝的茎段和叶片为接种外植体;诱导茎段产生腋芽的培养基为1/2MS 6-BA0.2~0.5mg/L NAA0~0.5mg/L,诱导叶片产生不定芽的培养基为1/2MS或MS 6-BA0.5mg/L NAA0.5mg/L;丛生芽快繁培养基MS 6-BA0.3mg/L NAA0.3mg/L,每20天继代一次,繁殖倍数20左右;生根培养基为1/2MS或MS,附加0.1~0.5mg/L的多效唑,对生根有促进作用。     

软枣猕猴桃原生质体酶解液配方筛选

[目的]筛选软枣猕猴桃原生质体最佳酶解液配方。[方法]以4种配方酶解液在相同条件下处理等量软枣猕猴桃叶片,比较最后收集的纯化原生质体量,筛选最佳酶解液配方。[结果]配方Ⅲ(1.0%纤维素酶、0.5%离析酶、0.3%果胶酶)和Ⅳ(1.0%纤维素酶、0.5%果胶酶)处理酶解效果要明显优于配方Ⅰ(2.0%纤维素酶、0.5%离析酶)、Ⅱ(2.0%纤维素酶、0.3%果胶酶)。[结论]配方Ⅲ(1.0%纤维素酶、0.5%离析酶、0.3%果胶酶)为软枣猕猴桃原生质体最佳酶解液配方。     

保水剂添加对刺槐根土力学特性的影响

为探究保水剂对根系生长和根土复合体力学特性的影响,为促进矿山植被恢复提供理论依据,在刺槐盆栽土中加入保水剂,3个处理分别为B1(0％),B2(0.3％)和B3(0.5％)。通过对比分析土壤养分,土壤酶活性,根系生长参数,根系抗拉力和根土复合体抗剪强度,以及它们之间的相关性,探究保水剂添加对根土复合体稳定性的影响。结果表明：(1)在0.3%和0.5%保水剂浓度梯度下,保水剂添加降低了刺槐根系的抗拉力;(2)不同保水剂浓度对刺槐根土复合体抗剪强度有不同效果,在0.3％保水剂浓度处理下,刺槐根土复合体抗剪强度显著降低,而在0.5％保水剂浓度处理下,刺槐根土复合体抗剪强度没有显著变化;(3)抗拉力、抗剪强度与纤维素,半纤维素呈负相关关系,与木质素呈正相关关系,刺槐根土复合体抗剪强度主要受内聚力影响。可见在0.3%和0.5%保水剂浓度梯度下,保水剂添加降低了刺槐根系拉伸性能,根土力学特性与根系内部成分显著相关。     

壳聚糖对异育银鲫溶菌酶和白细胞吞噬活性的影响

以壳聚糖为饲料添加剂,分5组(0％、0.3％、0.5％、1.0％、2.0％)对网箱养殖的异育银鲫(allogyogenetics silver crucian carp)进行不同添加剂量的饲养实验。经过2个月的饲养,分别从每组提取异育银鲫血清、脾脏和头肾上清液进行溶菌酶活性和白细胞吞噬活性实验,实验结果表明,添加0.5％或1.0％壳聚糖能有效地提高异育银鲫的溶菌酶活性(P<0.01)和白细胞的吞噬作用(P<0.01),该壳聚糖可被用作水产动物免疫增强剂,其在饲料中适宜添加量为0.5％。     

低硒饲粮中补钼、补硒对生长猪缺硒症及组织钼、硒含量、谷胱甘肽过氧化物酶活性的影响

45日龄断奶杂交猪44头喂以低硒基础饲粮及补钼0.5、10、100ppm、硒0.3ppm和同时补铝10ppm与硒0.3ppm的六种饲粮,研究补钼、补硒对猪缺硒症及组织生化指标的影响。结果表明:基础组猪亚临床缺硒、补钼可使之减轻。补钼显著提高血浆、心、肝硒含量及血浆、全血和肝谷胱甘肽过氧化物酶(GSH—P_X)活性。补10ppm钼和/或0.3ppm硒显著提高日增重,但补0.5与100ppm钼无影响。补硒对心、肝钼含量无影响。饲粮钼水平与心、肝钼含量显著相关。     

壳聚糖对异育银鲫溶菌酶和白细胞吞噬活性的影响

以壳聚糖为饲料添加剂,分5组(0％、0.3％、0.5％、1.0％、2.0％)对网箱养殖的异育银鲫(allogyogenetics silver crucian carp)进行不同添加剂量的饲养实验。经过2个月的饲养,分别从每组提取异育银鲫血清、脾脏和头肾上清液进行溶菌酶活性和白细胞吞噬活性实验,实验结果表明,添加0.5％或1.0％壳聚糖能有效地提高异育银鲫的溶菌酶活性(P<0.01)和白细胞的吞噬作用(P<0.01),该壳聚糖可被用作水产动物免疫增强剂,其在饲料中适宜添加量为0.5％。     

山新杨组织培养快繁技术研究

山新杨冬季枝条经FC处理，选择萌发新枝的茎段和叶片为接种外植体；诱导茎段产生腋芽的培养基为1/2MS+6-BA0.2~0.5mg/L+NAA0~0.5mg/L，诱导叶片产生不定芽的培养基为1/2MS或MS+6-BA0.5mg/L+NAA0.5mg/L；丛生芽快繁培养基MS+6-BA0.3mg/L+NAA0.3mg/L，每20天继代一次，繁殖倍数20左右；生根培养基为1/2MS或MS，附加0.1~0.5mg/L的多效唑，对生根有促进作用。     

秋水仙素诱导厚皮甜瓜倍性研究

为了成功获得厚皮甜瓜四倍体,研究其倍性特征,本试验用二倍体厚皮甜瓜M01-3为试材,用0.1%、0.3%、0.5%和0.7%的秋水仙素溶液通过涂抹法对子叶期和一叶一心期幼苗进行处理,并通过染色体计数法和细胞学鉴定法分析倍性。结果表明,已获得同源四倍体甜瓜,0.3%和0.5%的诱导率最高;与二倍体相比,四倍体植株长势好,叶形指数小,茎增粗,花冠大,花色艳,果肉变厚,可溶性固形物含量增加,气孔变大,叶绿体数目增多。     

精胺对哺乳仔猪小肠黏膜二糖酶比活力的影响

试验研究了哺乳仔猪口服精胺0、0.1、0.2、0.3、0.4、0.5 mmol·kg-1BW对小肠黏膜二糖酶比活力的影响。试验选取来自6窝11 d哺乳仔猪36头进行试验。试验采用完全随机区组设计,以窝别为区组,每头仔猪为试验重复,不同精胺剂量为处理,将同窝选取的6头试验仔猪随机分配到一个精胺剂量处理组中。口服精胺1次·d-1,持续3 d。试验结果显示,精胺没有改变仔猪生长性能(P0.05),却显著增加了十二指肠和空肠黏膜重量(P0.05)。增加口服精胺剂量线性提高了十二指肠和空肠黏膜麦芽糖酶和蔗糖酶比活力(P0.05),降低了乳糖酶比活力(P0.01)。试验结果表明,口服精胺改变了肠道黏膜二糖酶活性,提示精胺有促进幼龄哺乳仔猪小肠发育和成熟的效果,且适宜剂量为0.3~0.5 mmol·kg-1BW·d-1。     

日粮硒添加水平对9～12周龄泰和乌骨鸡生产性能及组织中黑色素含量的影响

选用9周龄初始体重无显著差异(P>0.05)的泰和乌骨鸡180只(公母各半),随机分成6组,分别饲喂在基础日粮中添加0(对照组)、0.1、0.3、0.5、0.7、0.9 mg/kg硒的试验日粮,每组设3个重复,每个重复10只鸡。试验期为4周。结果表明,日增重随日粮硒添加水平的提高呈先升高后下降趋势,0.3 mg/kg和0.5 mg/kg水平添加组显著高于对照组(P<0.05)。料重比随硒添加水平的提高呈先下降后升高趋势,0.3mg/kg硒添加水平能显著降低料重比(P<0.05),不同硒添加水平组相比差异不显著(P>0.05)。肝脏、肾脏、胸肌和皮肤黑色素含量随硒添加水平的提高呈先上升后下降的趋势。其中,当日粮硒添加水平为0.5mg/kg时,肝脏和胸肌黑色素含量达到峰值;当日粮硒添加水平为0.3mg/kg时,肾脏和皮肤黑色素含量达到峰值。     

喜树叶用园的密度效应

采用1年生喜树Camptotheca acuminata苗为材料建立喜树叶用园,设置造林密度为1.0 m×1.0 m （处理A为1.00万株·hm-2）,0.5 m×1.0 m （处理B为2.00万株·hm-2）,0.5 m×0.5 m （处理C为4.00万株·hm-2）,0.3 m×0.5 m （处理D为6.67万株·hm-2）,0.3 m×0.3 m （处理E为11.11万株·hm-2）5个水平的密度试验,分析不同密度对喜树个体高、径生长,叶面积,叶片数和叶生物量等指标的影响。结果表明:①密度对苗高生长有一定影响,但没有明显规律,差异不显著（P>0.05）。②平均地径、单株叶面积和单株叶产量均随密度的增加而递减,不同密度间存在显著差异（P<0.05）。③密度对叶用园单位面积叶产量有显著影响（P<0.05）,密度为1.00~4.00万株·hm-2范围内,单位面积叶产量随密度的增加而逐渐增加。之后,随密度的增加单位面积叶产量反而有所降低,以密度为4.00万株·hm-2条件下的单位面积叶产量为最大。     

Effect of salt stress on the physiological and photosynthetic characteristics of Weigela florida

Effects of salt stress on the physiological and photosynthetic characteristics of Weigela florida were studied. The results showed that the leaf area of Weigela florida was enhanced at 0.1% and 0.2% salt concentration, but decreased obviously when salt concentration was higher than 0.3%. The symptom of the salt injury was not significant when the salt concentration was lower than 0.3%, but was significant when higher than 0.4%. The water content decreased gradually but the electrolyle leakage increased gradually with the increasing of salt concentration and time. The total content of chlorophyll was rising while salt concentration was lower than 0.3%, but decreased while salt concentration was higher than 0.4%. The proline contents increased gradually while salt concentration was lower than 0.5%, but decreased at 0.5%. The soluble sugar content increased gradually with the increasing of salt concentration and prolonging of treatment, but decreased at 0.4% salt concentration 15 days after salt treatment. To the photosynthetic characteristics, the salt concentrations of 0.1% and 0.2% did not affect the photosynthetic characteristics of Weigela florida, when salt concentration was higher than 0.3%, the salinity significantly reduced Pn, Gs and Tr, but enhanced intercellular CO₂ concentrations at the salt concentrations of 0.3% and 0.4%. It was indicated that 0.1% and 0.2% salt concentrations had little influence on Weigela florida. The growth of Weigela florida was slightly decreased at the salt concentration of 0.3% without effect on its normal growth. However, the salt concentration of 0.4% affected the growth of Weigela florida obviously. Weigela florida died 7 days after treatment and it could not normally grow when salt concentration is higher than 0.5%.     

百合离体培养与植株再生体系的建立

以香水百合鳞叶为外植体,探讨不同外源激素水平对其小鳞茎分化、增殖与不定根形成的影响。结果表明:以MS+6-BA 0.5~1.0mg/L+IAA 0.1~0.3mg/L培养基的不定芽分化、增殖效果好,分化率达78.5%以上,增殖系数达5.6以上;1/2MS+6-BA 0.1mg/L+IAA 0.5mg/L或1/2MS+6-BA 0.1mg/L+NAA 0.1~0.3mg/L或1/2MS+6-BA 0.1mg/L+IBA 0.8mg/L的生根效果好,生根率可达96.0%以上;在泥炭∶珍珠岩=1∶1的基质中驯苗,成活率可达96.3%。     

欧李茎尖培养脱毒研究

以欧李嫩梢芽为外植体进行了微茎尖组培脱毒研究,探讨了在培养基中添加不同的激素成分及不同浓度对不定芽诱导、继代增殖和生根培养的影响。结果表明不定芽诱导的最佳培养基是:MS 6-BA0.4mg/l IAA0.5mg/L;增殖培养的最适培养基为MS 6-BA0.3 mg/L IAA0.4 mg/L;最佳生根培养基是:2/3MS IAA0.5 mg/L。应用指示植物鉴定法进行病毒检测显示,0.3-0.4mm茎尖培养对苹果褪绿斑病毒(ACLSV)和李矮缩病毒(PDV)的脱毒率为71.6%和73%,实验证明是一种可靠实用的方法。     

Search by mariner 10 for electrons and protons accelerated in association with venus

The University of Chicago instrumnents on board the Mariner 10 spacecraft bound for Mercury have measured energy spectra and fluxes of electrons from 0.18 to 30 million electron volts and protons from 0.5 to 68 million electron volts along the plasma wake and in the bow shock regions associated with Venus. Unusually quiet solar conditions and improved instrumentation made it possible to search for much lower fluxes of protons and electrons in similar energy regions as compared to earlier Mariner missions to Venus-that is, lower by a factor of 10(2) for protons and 10(3) for electrons. We found no evidence for electrons or protons either in the form of increases of intensity or energy spectral changes in the vicinity of the planet, nor any evidence of bursts of radiation in or near the observed bow shock where bursts of electrons might have been expected in analogy with the bow shock at the earth. The importance of these null results for determining the necessary and sufficient conditions for particle acceleration is discussed with respect to magnetometer evidence that Venus does not have a magnetosphere.