外源激素对杜衡叶柄愈伤组织诱导与分化的影响

以杜衡(Asarum forbesii Maxim.)叶柄为外植体,采用L9(34)正交实验设计分别研究了培养基中外源激素的种类及质量浓度对杜衡叶柄愈伤组织诱导和分化的影响,并据此筛选出适宜的诱导及分化培养基.结果表明:在杜衡叶柄愈伤组织的诱导过程中,培养基中细胞分裂素的种类(1.00 mg·L-16-BA、1.00 mg·L-1KT和1.00 mg·L-1ZT)和NAA质量浓度(0.00、0.10和0.30 mg·L-1)的影响效应均不显著,而2,4-D质量浓度(0.10、0.50和1.00 mg·L-1)则有显著影响(P<0.05);在愈伤组织的分化培养过程中,NAA(0.10、0.30和0.50 mg·L-1)的影响效应大于6-BA(1.00、3.00和5.00 mg·L-1)和IBA(0.01、0.05和0.10 mg·L-1).综合比较结果显示,适宜于杜衡叶柄愈伤组织诱导的培养基为添加1.00 mg·L-16-BA、0.30 mg·L-1NAA和1.00 mg·L-12,4-D的MS培养基(含6.5 g·L-1琼脂和30 g·L-1蔗糖,pH 5.8～pH 6.0),在此培养基上愈伤组织诱导率达到83.33%,且愈伤组织生长速度快、颗粒紧密;适宜于杜衡愈伤组织分化和不定芽增殖的培养基为添加3.00 mg·L-16-BA、0.10 mg·L-1IBA和0.30 mg·L-1NAA的MS培养基(含6.5 g·L-1琼脂和30 g·L-1蔗糖,pH 5.8～pH 6.0),在此培养基上愈伤组织的分化率最高(达到53.33%),增殖系数也最高(3.13).     

6-BA和氨基酸对黄瓜子叶离体培养成花的影响

在基本培养基的筛选中,1/2MS培养基中附加0.10 mg·L-16-BA能显著提高离体黄瓜子叶的开花率,White培养基中附加2.00mg·L-1的KT下开花率也有明显提高,但植株矮小、瘦弱,整株变黄,甚至透明化,长势极差.浓度在一定范围的6-BA(0.01～0.50mg·L-1)对黄瓜子叶开花率影响不大,但在高浓度(0.50 mg·L-1)下,植株生长势差,开花迟,低浓度(0.01 mg·L-1)下,生长势较好.相同浓度的L-丙氨酸和L-酪氨酸均明显促进黄瓜子叶开花,且开花早;而甘氨酸对黄瓜子叶开花则有一定的抑制,开花率低.     

NaCl胁迫对萝卜幼苗叶片生理特征及根尖细胞核形态的影响

对0.00(对照)～0.50 mol·L-1NaCl处理48 h后萝卜(Raphanus sativus L.)幼苗叶片的叶绿素含量、净光合速率、丙二醛(MDA)含量和相对电导率进行了测定,并观察了根尖细胞核形态变化和胁迫后幼苗生长的恢复状况.测定结果表明:经0.05 mol·L-1NaCl处理后,叶片的叶绿素含量和净光合速率均高于对照(0.00 mol·L-1 NaGl);而用0.10～0.50mol·L-1NaCl处理后,叶绿素含量和净光合速率均随NaCl浓度的提高逐渐降低且与对照差异显著,其中,经0.35 ～ 0.50 mol·L-1 NaCl胁迫处理后叶片净光合速率降至0.00μmol·m-2·s-1.随NaCl浓度的提高,MDA含量和相对电导率呈先快速上升而后逐渐下降的趋势,且均与对照差异显著;其中,经0.30 mol·L-1 NaCl处理后MDA含量最高,经0.40 mol·L-1NaCl处理后相对电导率最高.观察结果显示:经0.05～0.25 mol·L-1NaCl处理后根尖细胞核由规则的圆形向各种不规则形状转变,染色质出现不同程度的浓缩,表现出不同程度的程序性细胞死亡特征;经0.30 ～ 0.50 mol·L-1NaCl处理后则出现中空细胞与部分正常细胞并存的现象.经0.05和0.10 mol·L-1 NaCl处理后,萝卜幼苗可恢复正常生长,且株高与对照无明显差异;而经0.25 ～ 0.50 mol·L-1 NaCl处理后,幼苗均较难恢复正常生长,且随NaCl浓度的提高,幼苗出现枯萎、糜烂现象.研究结果显示:低浓度NaCl处理不仅对萝卜幼苗的生长、生理代谢及细胞核形态结构没有明显伤害反而有一定的促进作用,而高浓度NaCl胁迫可导致萝卜幼苗不可逆伤害.     

多效唑和矮壮素对盆栽彩色马蹄莲的矮化实验

采用200～400 mg*L-1多效唑(PP333)和1 000～2 000 mg*L-1矮壮素(CCC)对处于生长中期的2个彩色马蹄莲(Zantedeschia antedeschia)盆栽品种进行矮化处理,结果显示彩色马蹄莲的株型明显矮化,茎杆增粗.统计分析表明:PP333处理的矮化效果较明显,其中以300 mg*L-1效果最佳,说明PP333对设施栽培条件下彩色马蹄莲的防徒长、抗倒伏的矮化处理有实用价值.     

GA3、ABA对未成熟‘博Ⅱ优15’水稻种子萌发的影响

以未成熟水稻'博II优15'种子为材料,用不同浓度GA3、ABA浸种24 h,研究其对水稻种子萌发的影响.结果表明,GA3 0.10～2.00 g/L处理能极显著促进种子萌发,其中0.50 g/L效果最好,第4天发芽率高于对照(CK)56%;浓度大于0.50 g/L ABA处理显著抑制种子萌发;GA3与ABA协同处理时, GA3/ABA = 1:1(浓度0.05 g/L)和 GA3/ABA = 1:2(浓度0.01 g/L)均能极显著促进种子萌发,第7天种子发芽率分别比CK高30%和20%.进一步研究表明,GA3和ABA对未成熟水稻种子萌发的影响与α-淀粉酶活性相关.     

不同水体营养条件对刺苦草和密刺苦草生长的影响

以贡湖水体营养盐水平现状[ρ(TN)0.4~4 mg·L-1、ρ(TP)0.04~0.4 mg·L-1]为依据,研究不同梯度营养盐水体对刺苦草(Vallisneria spinulosa)与密刺苦草(V.denseserrulata)生长及生理的影响,探讨同属沉水植物对不同营养水体的响应差异。结果表明:水体营养条件对两种沉水植物的生物量累积没有显著影响;处理组刺苦草的最大株高分别增加了19%(P0.05)、63%(P0.05)、205%(P0.01),密刺苦草高浓度中植株最大株高与低浓度差异显著(P0.05);刺苦草与密刺苦草在高浓度水体中的克隆繁殖能力分别下降了30%和20%;低浓度水体中刺苦草与密刺苦草叶片丙二醛含量增加(P0.05),叶绿素含量减少(P0.05),表明其受到养分胁迫;在ρ(TN)1.5~4 mg·L-1、ρ(TP)0.15~0.4 mg·L-1范围内,两种苦草表现出较强适应性。     

不同氮源对苦草(Vallisneria natans)生长及生理指标的影响

通过实验室静态模拟,研究了在富营养条件下(4.0 mg.L-1TN,0.2 mg.L-1TP)不同比例铵态氮和硝态氮(6∶0、5∶1、3∶3、1∶5和0∶6)对苦草〔Vallisneria natans(Lour.)Hara〕的生长与生理指标的影响。结果表明,随着铵态氮和硝态氮比例的下降,苦草相对生长率和蛋白质含量先升高后下降,超氧化物歧化酶(SOD)和谷氨酰胺合成酶(GS)活性逐渐下降,硝酸还原酶(NR)活性逐渐升高。在4.0 mg.L-1TN和0.2 mg.L-1TP条件下,若不考虑磷的作用,高浓度铵态氮对苦草的生理功能有影响,对其生长有明显的抑制作用;而当铵态氮浓度小于0.67 mg.L-1时却可以促进苦草的生长。     

角蒿和铁线莲的矮化试验

为了提高株型较高的毛子草 (Incarvilleaarguta)和半藤本性状的毛茛铁线莲 (Clematisranuncu loides)的观赏价值 ,我们用多效唑、矮壮素和丁酰肼对它们进行了多种矮化处理。试验结果表明每盆用 0 .4g5 0 %多效唑可湿性粉剂施于土壤 ,每两周全株喷 0 .2 5 %的矮壮素并结合打顶可明显抑制第三年生毛子草的株高、花穗和羽状复叶的生长 ,增加了花穗数和花蕾总数 ,开花期比对照延长约 1 0d。每两周全株喷 0 .76%丁酰肼并结合打顶可抑制毛茛铁线莲的枝条生长 ,促进分枝 ,增加花蕾数。对两种植物的矮化均表明矮化处理过的植株对白粉病有较强的抗性     

培养条件对螺旋藻生长和藻胆蛋白含量的影响

研究了不同质量浓度尿素代替硝酸钠作氮源和不同氯化钠质量浓度改变渗透压对螺旋藻的生长和藻胆蛋白含量的影响。结果发现适宜质量浓度尿素 ( 0 .1g·L-1)培养可加快螺旋藻生长 ,增加藻胆蛋白含量 ;质量浓度高于 0 .2g·L-1其生长受到抑制 ;而质量浓度过高 (≥ 0 .4g/L)时培养几天螺旋藻即断裂并逐渐死亡。培养基中不加氯化钠或质量浓度为 2 0g·L-1时培养 ,生长速度均与对照相当 ,但藻胆蛋白含量比对照要高 ;质量浓度为 40g·L-1～ 6 0g·L-1时培养 ,其生长明显变慢 ,且氯化钠浓度越高生长越慢 ;当质量浓度过高 (≥ 6 0g·L-1)时培养 3d ,螺旋藻细胞即破裂死亡。     

山核桃外果皮黄酮提取液对小麦和绿豆幼苗的化感效应

以盆栽小麦和绿豆幼苗为材料,研究了7个浓度山核桃外果皮黄酮提取液(0.02～0.14 mg·L-1)处理对小麦和绿豆幼苗生长及其叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性、氧自由基(O2)、丙二醛(MDA)含量、相对电导率的影响.结果显示:在试验浓度范围内,各处理对小麦和绿豆生长具有促进作用;0.06～0.08 mg·L-1黄酮提取液对小麦苗高和根长的影响极显著(P<0.01),0.06 mg·L-1时根长和苗高的化感效应指数(RI)分别为0.136和0.120;0.12 mg·L-1黄酮提取液对绿豆胚根和胚轴具有极显著促进作用,对下胚轴和胚根的化感效应指数分别为0.147和0.123;适宜浓度黄酮提取液能显著提高小麦和绿豆幼苗叶片SOD、POD的活性,同时显著降低其O2产生速率、MDA含量和相对电导率.研究表明,适宜浓度的山核桃外果皮黄酮提取液具有促使小麦和绿豆幼苗生长、提高其叶片保护酶活性和增强细胞膜结构稳定性的作用.     

Effect of phosphorus fertilizer on A values for soils cropped with winter wheat

The effect of successive annual fertilizer P applications (30 kg P ha⁻¹yr⁻¹) on A values (plant availability) for four soils cropped with winter wheat, was investigated over a four-year period under field conditions in the Southern Plains, USA, using P-32 as a tracer. With successive annual fertilizer P applications, winter wheat dry matter yield and A value increased. This increase was linear for wheat yield on each soil (r²=0.77 to 0.97). For A value, the increase was a positive linear function of residual Bray-I P (r²=0.99 to 1.00) and a negative linear function of P-sorption index of the soil (r²=0.94 to 0.98). This was attributed to the fact that continued fertilizer P applications, by decreasing P-sorption index, increased amounts of available P. Consequently, utilization of fertilizer P decreased with successive applications and A value, thus, represents total soil P availability, including native and residual (carry over) fertilizer P. These results confirm earlier suggestions that the A value may be used as a quantitative measurement of environmental and soil factors influencing P availability.     

Changes of phosphorous fractions under continuous corn production in a temperate clay soil

Limited efficiency of fertilizer P may be improved through an understanding of soil P fraction changes with time. This study examined sequential changes in soil organic P (Po) and inorganic P (Pi) in a Ste. Rosalie clay (Humic Gleysol; fine, mixed, frigid, Typic Humaquept) under continuous corn with and without P fertilization. Soil P was fractionated into Bicarb-Pi and Po, NaOH-1-Pi and Po, HCl-Pi, NaOH-Pi and Po, and Residue-P. In the non-P fertilized plots, soil total extractable Po declined by 14% of the initial value over five years of corn production, whereas soil Pi fractions were unchanged. The losses of soil Po were mainly from NaOH-1-Po. Added fertilizer P increased NaHCO3-Pi and NaOH-1-Pi in plots receiving 44 and 132 kg P ha^-1 yr^-1 and increased Residue-P in plots receiving 132 kg P ha^-1 yr^-1. Although NaOH-1-Po decreased slightly in the plots receiving 44 kg ha^-1 yr^-1 P fertilizer, total soil extractable Po was maintained in P fertilized plots. Mineralization of from 16 to 29 kg P ha^-1 yr^-1 Po was needed to account for soil Po losses. Bicarb-Pi and NaOH-1-Pi appeared to be most important for assessment of soil P fertility changes in long-term fertilized soils.     

Sesquiterpenoids of fourteen Plagiochila species

The distribution of ent-2,3-secoaromadendrane-, ent-aromadendrane-, ent-bicyclogermacrane- and ent-maaliane-type sesquiterpenoids in fourteen Plagiochila species is described. These sesquiterpenes are the significant chemosystematic markers of Plagiochila. The intense pungent substance of some Plagiochila species is due to an ent-2,3-secoaromadendrane-type sesquiterpene hemiacetal, plagiochiline A.     

The biological transformation of P in soil

Summary Organic forms of soil phosphorus (P_o) are an important source of available P for plants following mineralisation. The rates and pathways of P through soil organic matter are, however, poorly understood when compared to physco-chemical aspects of the P cycle. The essential role of soil microorganisms as a labile resercoir of P, confirmed experimentally and in modelling studies, has recently led to the development of methods for measuring thier P content. Incorporation in a new P fractionation scheme of these measurements with estimates of P_i and P_o fractions that vary in the exten toftheir availability to plants has enabled the dynamics of short-term soil P transformations to be investigated in relation to long-term changes observed in the field.Different types of soil P compounds that minearlise at different rates can now be measured directly in extracts by³¹P-nuclear magnetic resonance. Orthophosphate diesters, including phospholipids and nucleic acids, are the most readily mineralised group of these compounds. However, mineralisation rates rather than the amounts of types of P_o in soil ultimately control P availability to plants. These rates are influenced by a number of soil and site factors, as a sensitive new technique using [³²P] RNA has recently shown.These recent developments reflect a more holistic approach to investigation of the soil P cycle than in the past, which should lead to improved fertilizer management practices.Introductory lecture     

Uptake of phosphate from soils and fertilizers as affected by soil P availability and solubility of phosphorus fertilizers

Fertilizers labelled with ³²P were used to measure amounts of phosphorus, P_s and P_F, taken up by Lolium perenne from available soil P and from P fertilizer respectively, when applied at a rate of 66 mg P·(kg soil^–1) in greenhouse experiments. The quantity P_s of phosphorus taken up from soil in the presence of P fertilizer was compared to the quantity P_o taken up from soil without P fertilizer. The quantity (P_s–P_o) is positive for low P_o values, i.e. in soils poor in available phosphorus, but is negative for high P_o values indicating that an input of P fertilizer can induce a decrease in the utilization of available soil phosphorus. Moreover, for a given soil, the quantity (P_s–P_o) depends on the chemical form of the fertilizer. The standard method of evaluation of P fertilizer efficiency is based on the assumption that P_s=P_o, but P_s can differ from P_o. This result can explain the contradictory data published from field experiments about the efficiency of the various P fertilizers.     

中国东北地区地卷属地衣的研究

本文作者根据前人的文献资料,对中国科学院林业土壤研究所1950年以来在东北地区所采集的1200余号地卷属地衣植物标本进行整理、研究,共报道23个种,其中8个种为东北地区新分布。本文包括属的特征、分种检索表、种的文献考证、生境、产地以及国内外的地理分布。     

Effect of silicon on the growth and phosphorus uptake of rice

A pot experiment was conducted to measure the effect of silicon on phosphorus uptake and on the growth of rice at different P levels. Rice (Oryza sativa L. cv. Akebono) was cultured in Kimura B nutrient solution without and with silicon (1.66 mM Si) and with three phosphorus levels (0.014 mM P, low; 0.21 mM, medium; and 0.70 mM, high).Shoot dry weight with Si (+Si) in solution increased with increasing P level, while shoot weight without Si (–Si) was maximum at 0.21 mM P, suggesting that +Si raised the optimum P level for rice. +Si increased shoot weight more when P was low or high than when P was medium.The concentration and amount of inorganic P in shoots increased with increasing P level. +Si did not significantly decrease P uptake by rice at 0.014 mM P, however, uptake at 0.21 and 0.70 mM P was 27 and 30 percent less than uptake with –Si, respectively. In –Si with 0.21 and 0.70 mM P, inorganic P in shoots was more than double the concentration in shoots grown in +Si solutions.The Si concentration in shoots decreased slightly with increasing P level, although Si uptake was not significantly affected by P. +Si decreased the uptake of Fe and Mn by an average of 20 and 50 percent, respectively, thus P/Mn and P/Fe ratios increased in the shoot when P was low.From the results above, the beneficial effect of Si on the growth of rice was clearly shown when P was low or high. This effect may have resulted from decreased Mn and Fe uptake, and thus increased P availability within P deficient plants, or from reduced P uptake when P was high.     

Mobilization of different phosphate fractions in the rhizosphere

Availability of soil P fractions and mechanisms of acquisition by plants were studied. Plants mobilize soil P by desorption via depletion of P solution concentration around roots. In an oxisol, the process was enhanced by nitrate N nutrition of ryegrass, which increased soil pH, and by carboxylate release by white lupin. Ligand exchange and Fe/Al solubilization are assumed to be the mechanisms. Ammonium N nutrition of ryegrass decreased pH and allowed P mobilization in a luvisol but had no such effect in an oxisol, due to acid solubility of P in these soils. Organic P dissolved in soil solution contributed one third to the P uptake of field-grown barley on a luvisol. Laboratory experiments suggest that organic P is hydrolyzed by phosphatases at the root surface and replenished by micro-organisms.     

氮磷营养因子对赤潮异弯藻生长的影响

研究了N、P营养浓度对赤潮异弯藻(Heterosigma akashiwo)生长的影响.结果表明,该藻的生长速率与N、P营养因子浓度的关系符合Monod公式.在NO₃^--N浓度达到7.5 mg·L^-1时,赤潮异弯藻开始生长;浓度为3.75～75 mg·L^-1时,赤潮异弯藻的比生长速率与NO₃^--N浓度成正比关系.N营养充足时,赤潮异弯藻的最大生长速率μ_m-n=0.3475·d^-1,K_s-n=18.91 mg·L^-1.PO₄^--P浓度为0～1.0 mg·L^-1时,赤潮异弯藻的比生长速率与P浓度成正比关系;P营养充足时,赤潮异弯藻的最大生长速率μ_m-p=0.3024·d^-1,K_s-p=0.4086 mg·L^-1.N/P达到25后藻细胞浓度达到最大,表明N/P为25时最适合赤潮异弯藻生长.赤潮异弯藻最适合在N 37.5～225.0 mg·L^-1、P 5.0～50.0 mg·L^-1、N/P=25条件下生长.     

不同磷效率小麦品种对缺磷胁迫反应的比较

在营养液培养条件下,以根据相对产量为指标筛选出的6个不同磷效率的小麦(Triticum aestivum L.)品种为材料,对其苗期在缺磷条件下生长、根冠磷含量及其分配,以及叶片韧皮部汁液中磷浓度等进行了比较研究.结果表明,缺磷抑制植株地上部生长,但刺激根系生长,导致植株根/冠比增加.无论在供磷或缺磷条件下,磷高效品种的根冠生长速率都低于磷低效品种.缺磷导致植株体内的磷含量下降与根系相比,地上部磷含量的下降速率更快.但在缺磷条件下,不同磷效率的小麦品种根冠间的磷分配变化没有差异.研究发现,在正常供磷条件下,磷高效小麦品种的叶片韧皮部汁液中磷浓度较低,而磷低效品种的叶片韧皮部汁液中磷浓度较高.但开始缺磷后,磷高效品种的叶片韧皮部汁液中的磷浓度下降较慢,使其相对磷浓度较高.缺磷后1 0天,磷低效品种叶片韧皮部汁液中的磷浓度为供磷对照的35.9%,而磷高效品种叶片韧皮部汁液中的磷浓度为供磷对照的59%.