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1.
The changes of the antioxidant (AOA) and antiradical activities (ARA) and the total contents of phenolics, anthocyanins, flavonols, and hydroxybenzoic acid in roots and different aerial sections of Echinacea purpurea, nettle, and dandelion, after treatment with ornithine decarboxylase inhibitor, a polyamine inhibitor (O-phosphoethanolamine, KF), and a phenol biosynthesis stimulator (carboxymethyl chitin glucan, CCHG) were analyzed spectrophotometrically; hydroxycinnamic acids content was analyzed by RP-HPLC with UV detection. Both regulators increased the AOA measured as inhibition of peroxidation (IP) in all herb sections, with the exception of Echinacea stems after treatment with KF. In root tissues IP was dramatically elevated mainly after CCHG application: 8.5-fold in Echinacea, 4.14-fold in nettle, and 2.08-fold in dandelion. ARA decrease of Echinacea leaves treated with regulators was in direct relation only with cichoric acid and caftaric acid contents. Both regulators uphold the formation of cinnamic acid conjugates, the most expressive being that of cichoric acid after treatment with CCHG in Echinacea roots from 2.71 to 20.92 mg g(-1). There was a strong relationship between increase of the total phenolics in all sections of Echinacea, as well as in the studied sections of dandelion, and the anthocyanin content.  相似文献   

2.
The present study was carried out to find the influence of some organic materials on the optimum biomass production of Chrysopogon zizanioides (L.) Roberty (Vetiver) using soil (S), vermicompost (VC), cow dung (CD) and coir pith (CP) at different ratios. The final day results showed that the ideal combination for the growth of the Vetiver is 1:1:1:1 v/v ratio of VC/CD/CP/S. The pH, electrical conductivity (EC), nitrogen (N)- phosphorus (P)- potassium (K), organic carbon (OC), and carbon (C)/N ratio showed in 1:1:1:1 v/v ratio of (VC/CD/CP/S), on 120th day were 7.3, 0.38 dS m?1, 1.36%, 0.11%, 8.7%, 20.5% and C/N ratio is 15:1. The root and shoot length, fresh weight, dry weight, number of culms, and total chlorophyll content of Chrysopogon zizanioides were 65cm, 197 cm, 312 g, 104.4 g, 36 culms/plant and 40.57 mg/g at 1:1:1:1 v/v ratio of (VC/CD/CP/S) treatment and compared to control sets, the increasing ratio were 6:1, 3:1, 12:1, 12:1, 3:1, 2:1 respectively.  相似文献   

3.
Root and aerial sections (flower, stem, and leaf) of Echinacea purpurea were dried with hot air at temperatures in the range of 40-70 degrees C, and the concentrations of alkylamides and cichoric acid were determined after drying. Increasing drying temperature decreased from 48 h at 40 degrees C to 9 h at 70 degrees C but resulted in a decreased concentration of cichoric acid in all plant sections with a greater loss from aerial plant parts than from the root. There was, however, no significant difference in the concentration of the alkylamides at any drying temperature. Establishment of operational parameters for the drying of echinacea must therefore be structured around the more labile cichoric acid.  相似文献   

4.
Quantitative phytochemical variation was determined from roots and inflorescences of native plant populations in the genus Echinacea. Specimens were collected in situ throughout the natural range of each putative taxon and transplanted to greenhouse cultivation. Ethanolic extracts from individual plants were separated by reversed-phase HPLC to quantify the alkamides, polyenes/ynes, and phenolics, and then grouped by age and taxonomically, according to a recent morphometric taxonomic revision of the genus. Canonical discriminant analysis revealed that cichoric acid, the diene alkamides 1-3 and 7, and ketoalkene 24 were the best taxonomic markers. Mean content for each of 26 phytochemicals revealed useful agronomic information, such as those varieties and organs with the highest accumulations, as well as the optimal age and growth conditions for each variety. The highest amounts of cichoric acid were measured from the older, wild inflorescences of E. pallida var.sanguinea, whereas the highest quantities of the alkamides 1-3 and 7 were present in roots of wild and transplanted E. purpurea. Baseline phytochemical data and chromatographic profiles for all types of wild Echinacea may be used for protection of wild stands, germplasm identification, and crop improvement.  相似文献   

5.
玉米苗期根系生长与耐低磷的关系   总被引：20，自引：5，他引：20  
在田间筛选试验的基础上,利用两个磷高效(181和186)、两个磷低效(153和197)玉米自交系,进一步研究了这些自交系苗期耐低磷能力差异及其与根系生长的关系。结果表明,在低磷胁迫(P.5.78.mg/kg)下,所有自交系玉米地上部重量、初生根重、次生根重及磷累积量降低,但磷高效自交系181和186受影响程度显著小于153和197。在试验所处的玉米生育时期(6叶龄),磷对所用自交系的初生根及次生根数量没有影响。比较181和197的根系形态,在低磷胁迫下,磷低效自交系197的初生根侧根长、轴根长均显著下降,磷高效自交系181则下降幅度很小。而且,低磷使181初生根的侧根/轴根比值、根长度/根重比值较高。说明低磷胁迫下,181自交系可以将根中的有限的养分及干物质作更合理的分配,促进细根的生长,从而获得较长的根系。  相似文献   

6.
发根农杆菌介导转化小金海棠的影响因素   总被引：2，自引：1，他引：1  
为了研究发根农杆菌介导的小金海棠的遗传转化体系,采用农杆菌侵染的方法,对影响Ri质粒诱导小金海棠产生发状根的各种因素进行了研究,结果发现,Ri质粒转化小金海棠形成发状根的效率,受发根农杆菌种类、浓度、生理状态及小金海棠外植体的种类、外植体在菌液中的侵染时间、共培养时间、基本培养基等多种因素的影响,加入20mg/L AS对转化效率影响不大。采用稀释5倍的处于对数生长期的8196菌株,感染小金海棠无菌苗幼嫩叶片5-10min,在MS培养基上共培养2d后转入含卡那霉素10mg/L、头孢霉素250mg/L的1/4MS诱导培养基上培养一个月,发根诱导效率最高可达93.3%.随机选择50条诱导的发根进行GUS染色,结果发现有96%发根GUS染色呈阳性。对48条GUS阳性的发根进行PCR检测,其阳性率为100%。高效的发根诱导体系为发根的进一步再生及转入外源基因奠定了基础。  相似文献   

7.
灌水下限与毛管埋深对温室番茄生长的影响   总被引：1，自引：0，他引：1  
为探明番茄根系生长与水分分布之间的互反馈机制,通过日光温室地下滴灌试验,设置了4种毛管埋深(0 cm、10 cm、20 cm和30 cm)和3种灌水下限(保持土壤含水量为50%、60%和75%田间持水量),研究了不同灌水下限与毛管埋深对番茄根系生长及干物质分配的影响。研究结果表明,轻度、中轻度水分亏缺(灌水下限为75%和60%田间持水量)时,毛管埋深对番茄耗水量有显著影响,10~20 cm毛管埋深提高番茄耗水量。毛管埋深增加会减少0~20 cm土层根系分布,促进20~60 cm土层根系生长;毛管埋深对0~10 cm、20~30 cm、30~40 cm土层根系生长影响显著,对50~60 cm土层根系生长无显著影响。灌水下限对细根(d1 mm)、粗根(d1mm)的根长与根表面积影响显著,毛管埋深对细根的根长与根表面积有显著影响;轻度水分亏缺及20 cm毛管埋深有利于细根根长和根表面积生长,减少粗根比例。本研究结果表明,轻度水分亏缺及毛管埋深为20 cm更有利于全株干物质积累,灌水下限为75%田间持水量能够增加根系干物质分配比例,而20 cm毛管埋深则能促进干物质向茎叶转移且减少根系干物质的分配比例。  相似文献   

8.
【目的】研究缺锌对玉米根系生长及根系中生长素含量与生长素运输关键基因表达的影响,揭示缺锌胁迫下玉米根系生长与生长素响应特征。【方法】以郑单958玉米为材料,进行营养液培养试验,设置Zn 0缺锌 (0 μmol/L) 和正常供锌 (1 μmol/L) 两个处理。植株干样经硝酸–过氧化氢消煮,利用原子吸收分光光度计测定消煮液锌浓度。保存于FAA溶液 (70% 乙醇︰38% 甲醛︰乙酸 = 90︰5︰5,体积比) 中的根系样品,经洗涤扫描获得数字图像,利用WinRHIZO软件分析得到根长、根表面积、根体积等指标;采用气相色谱-质谱联用仪检测根系中生长素吲哚乙酸含量;采用实时荧光定量PCR技术对玉米根系生长素转运基因ZmAUX1和ZmPIN1c表达进行定量分析。【结果】缺锌胁迫下,植株地上部锌含量低于20 μg/g,生物量显著降低;缺锌根系表面积与体积变小,总根长、侧根总长度与侧根平均长度变短,侧根密度增大,直径变细。缺锌条件下,距根尖2 cm的区域中生长素较正常供锌处理降低近30%。缺锌根系中ZmAUX1和ZmPIN1c基因表达明显受抑。【结论】缺锌胁迫下玉米根系中生长素转运关键基因表达降低,生长素含量下降,生长素分布改变,影响根系生长发育。  相似文献   

9.
  【目的】  钾在氮代谢中发挥重要作用,通过同位素示踪技术,研究供钾水平和稳定性对苹果矮化砧M9T337幼苗生长及氮素吸收利用的影响,以深化理解钾素水平对苹果氮素吸收利用的影响机制,为苹果生产上科学施钾提供理论依据。  【方法】  以苹果矮化砧M9T337幼苗为试验材料进行砂培试验,总处理周期为60天。以Hoagland营养液为基础,设置5个供钾处理,分别为持续低钾 (K 0.5 mmol/L,K1)、1～30天低钾 (0.5 mmol/L) 和31～60天高钾 (12 mmol/L,K2)、适量稳定供钾 (6 mmol/L,K3)、1～30天高钾 (12 mmol/L) 和31～60天低钾 (0.5 mmol/L,K4)、持续高钾 (12 mmol/L,K5)。每3天更换一次营养液,每次在营养液中加入0.01 g Ca(15NO3)2,共加入0.2 g。于处理后第31天和第60天取样,测定幼苗生长、根系性状以及氮素吸收利用分配状况。  【结果】  供试苹果砧木幼苗处理第60天,以适量稳定供钾处理K3的生物量最大,根系总长、总表面积最大,根系活力也显著高于其他处理。31～60天,K2处理地上部干重增幅最大 (174.8%),K4处理根系干重增幅最大 (176.3%),幼苗总生物量、根系长度、根系总表面积增量最大的处理为K3 (依次为12.99 g/株、1059 cm/株和1113 cm2/株)。第31天和第60天两次测定结果显示,幼苗根部NO3–吸收速率均以K3处理最大,分别为29.63和36.19 pmol/(cm2·s);K1、K4处理幼苗根部NO3–离子流在第31天时为内流,在第60天时变为外排。整个处理期内,硝酸还原酶 (NR) 活性均以K3处理最高;处理41～60天,K2处理幼苗NR活性显著升高,而K4处理则显著降低。15N示踪结果表明,K3处理下苹果砧木幼苗对氮素的吸收能力最强,植株总吸氮量、15N利用率和叶片15N分配率均显著高于其他处理;处理第60天15N吸收量表现为K3>K5>K2>K4>K1。  【结论】  持续的低钾、高钾以及变换性的高低钾处理会抑制苹果幼苗根系生长以及氮素向地上部运移,不利于氮素的吸收利用。而持续适宜稳定地供钾可以提高根系活力和硝酸还原酶活性,保持根系较高的NO3–吸收速率,同时促进氮素由根系向叶片的运移,实现对氮素的高效吸收利用,从而促进苹果砧木幼苗的生长。  相似文献   

10.
  【目的】  根系构型影响作物的抗旱能力,研究磷肥施用深度调节苦荞根系分布的可行性,为贫瘠干旱地区苦荞的生长提供科学养分管理措施。  【方法】  以‘黑丰1号’苦荞 (Fagopyrum tataricum L.) 为试验材料,进行根管土柱 (直径25 cm、高50 cm) 栽培试验,设置田间持水量65%～75% (W1)、45%～55% (W2) 和35%～45% (W3) 3种土壤水分条件,磷肥施用深度分别设置距离地表10 cm (P10)、20 cm (P20)、30 cm (P30) 以及3层均匀施用 (P-all) 4种方式,共有12个处理。在苦荞幼苗三叶一心期进行处理,生长22天后取样,测定根系构型,并记录生物量。  【结果】  干旱胁迫抑制了苦荞植株生长、干物质量的积累以及根系发育,其中W3水分条件抑制作用最为明显,导致苦荞株高、茎粗和叶面积较W1水分条件分别下降17.20%、18.03%和23.17%;根长、根表面积和根体积分别下降16.97%、20.39%和17.39%;地上部干物质量和根系干物质量分别下降39.16%、28.60%。干旱胁迫促进根系下扎,增加深层土壤中的根系分布。与W1水分条件相比,W2、W3水分条件下0—10和10—20 cm土层平均根长分别下降30.18%和27.55%、41.83%和41.02%,根系干物质量分别下降36.62%和33.61%、49.72%和48.11%;而20—30和30—45 cm土层中的苦荞平均根长则分别增加33.53%和42.52%、31.74%和50.95%,根系干物质量分别增加13.70%和26.84%、5.85%和28.64%。深层施磷促进施磷层土壤根系生长,与P-all处理相比,P10处理10—20 cm土层根长平均增加18.96%,P20处理20—30 cm土层平均增加32.39%,P30处理30—45 cm土层平均增加28.73%,根系干物质量依次分别增加26.62%、30.74%和24.65%。方差分析结果表明,各水分处理条件下,0—10和10—20 cm土层根系干物质量均表现为P10处理显著高于其他施磷处理,且其他处理间差异也达显著水平;而20—30、30—45 cm土层根系干物质量则表现为P20、P30施磷处理显著高于其他处理。  【结论】  水分和施磷深度对苦荞苗期植株生长以及根系分布均有显著影响。在干旱胁迫下,增加磷肥的施用深度可促进苦荞根系在20—45 cm深土壤中的分布,显著扩大根系对土壤养分和水分的获取空间,并最终促进苦荞的生长。本试验条件下,采样仅限于苦荞苗期,在水分胁迫条件下磷肥以10 cm的施肥深度效果最佳。  相似文献   

11.
滴灌苜蓿田间土壤水盐及苜蓿细根的空间分布   总被引：3，自引：2，他引：1  
为了明确滴灌苜蓿土壤水、盐运移,细根分布及细根生物量动态,该文对苜蓿进行滴灌和漫灌试验,结果表明,漫灌水分集中在15 cm浅层土壤内且分布均匀,含水率在19.5%~20.5%之间。滴灌水分高值区集中在水平方向距滴头15 cm,深度为40 cm的土层中,含水率达到18.0%~20.0%。漫灌对0~25 cm深度土层盐分淋洗作用明显,土水比1:5土壤水提液的电导率由灌前的0.4~0.5 m S/cm下降到0.3 m S/cm以下;滴灌可使根区盐分下降至0.2 m S/cm,显著低于灌溉初始的盐分含量(P0.05)。与漫灌比较,滴灌苜蓿细根集中分布在水平方向距滴头0~30 cm,垂直深度0~50 cm范围内。生长季各时间节点滴灌细根总量高于漫灌,其平均值分别为211.6和198.3 g/m2。滴灌和漫灌各时间节点细根量表现出明显的波动,其范围分别在193.2~243.6和182.7~219.1 g/m2之间。在整个生长期内,滴灌活根量高于漫灌,且生长前期滴灌死根量变化较漫灌平稳。活细根和死细根之间的周转使得两者呈现出此消彼涨的状态,表明细根具有生长-凋亡-再生长的周期性。该研究可为滴灌技术在苜蓿栽培上的应用提供参考。  相似文献   

12.
【目的】研究植物根际促生菌及其代谢产物对作物生长的促进效应及其机制,为制备高效微生物肥料提供优良的菌种资源和应用技术支持。【方法】枯草芽孢杆菌枯草亚种(Bacillus subtilis subsp. subtilis)NRCB002发酵液组分的促生效应盆栽试验设置了5个处理,分别为发酵培养基(P)、发酵菌液(F)、发酵菌液上清液(S)、重悬菌液(G)和重悬菌液+乙偶姻(A),以浇灌等量的去离子水的处理为对照(CK)。进一步的乙偶姻施用方式盆栽试验设置两个处理,分别为在生菜幼苗根部浇灌(RI)、叶面喷施(FS) 0.1 g/L乙偶姻溶处理,以施用等量去离子水的处理为对照(CK)。生菜生长两周后,两组盆栽试验收获地上部及根系,测定株高、叶面积、地上部和根部的鲜重和干重,并分析根系指标。以K氏培养基为基础培养基,添加0、0.075、0.375、1.5 g/L的乙偶姻培养NRCB002,采用结晶紫染色法测定了NRCB002生物膜的形成量。【结果】1)与CK相比,除培养基P处理外,其余4个处理均显著提高了生菜幼苗的地上部和根部的鲜、干重;S、F和A处理还显著增加了生菜幼苗的株高、叶面积、总根长...  相似文献   

13.
[目的]针对攀枝花烟区烤烟移栽伸根期干旱、烟苗发育迟缓等问题,研究菌丝营养钵对烤烟根区微生态水肥环境和烟苗生长的影响.[方法]将玉米秸秆切碎后隧道式微波灭菌,利用灰管层孔菌(Fomes lignosus)的速生、菌丝扭结力强、快速腐解纤维素等特点,通过菌丝缠绕玉米秸秆制作成自然降解的圆锥型杯状烟苗移栽营养钵.将菌丝营养...  相似文献   

14.
3-Hydroxy-4,5-dimethyl-2(5H)-furanone (sotolone) and 3-amino-4,5-dimethyl-2(5H)-furanone, the postulated precursor of sotolone, were detected in hairy root cultures of Trigonella foenum-graecum (fenugreek) by GC-MS. The hairy root cultures in both conical flasks and airlift with mesh bioreactors were achieved from hypocotyl of seedling by infection with Agrobacterium rhizogenes. In flasks, the mathematical relationship between hairy root growth and conductivity was established and afterward used to evaluate the biomass evolution in bioreactor cultures due to the difficulty of obtaining direct biomass samples from the bioreactor. The GC-MS analyses of ethanolic extracts from hairy roots revealed the presence of two important compounds: sotolone (1.2% of the volatile fraction) and 3-amino-4,5-dimethyl-2(5H)-furanone (17% of the volatile fraction). These results point out that biotechnological production of sotolone in bioreactors is possible. Additionally, these hairy root cultures offer, for the first time, an excellent biological model to study the biosynthetic pathway of sotolone in fenugreek.  相似文献   

15.
提高营养液镁浓度可缓解黄瓜幼苗亚低温胁迫   总被引：1，自引：0，他引：1  
【目的】我国北方地区冬春季栽培黄瓜经常遭受亚低温 (15℃/8℃) 胁迫,用标准营养液育苗常会造成黄瓜植株矮小、叶片发黄等问题。研究调整营养液中镁和钾离子浓度,以便达到缓解亚低温对黄瓜幼苗伤害作用的目的。【方法】选用‘博耐 3000'黄瓜幼苗为试材,利用人工气候箱,以常温 (25℃/18℃) 下黄瓜山崎标准营养液配方 (K+ 6 mmol/L、Mg2+ 2 mmol/L) 为对照,在标准营养液其他元素保持不变的基础上,设置两个钾离子水平 (K+ 6、12 mmol/L),4 个镁离子水平 (Mg2+ 2、4、6、8 mmol/L),在亚低温 (15℃/8℃) 下栽培黄瓜幼苗,于处理后幼苗生长的 0、7、14、21 d 调查了不同镁钾水平营养液栽培的黄瓜幼苗的根系形态、干物质积累和分配以及对钾和镁元素吸收。【结果】1) 亚低温下适当增加营养液中的 Mg2+ 浓度,能显著提高黄瓜幼苗的壮苗指数,当营养液中 Mg2+ 和 K+ 均为 6 mmol/L 时,壮苗指数达到最大值 0.17;2) 镁和钾对根系形态影响不同,K+ 浓度与根长和根系总表面积成正相关,且主要影响直径范围为 0～0.5 mm 的根系,Mg2+ 与根系平均直径正相关且主要影响 > 1.0 mm 的根系;较高的 K/Mg 比例有利于黄瓜 0～0.5 mm 根系的生长,根系总长和总体积的增加,但显著抑制了 0.5～1.0 mm 和 > 1.0 mm 根系的生长。3) 亚低温下,茎叶中干物质量降低而根中升高,在 K1 (6 mmol/L) 水平时,随 Mg2+ 浓度升高,根和茎中干物质量升高,叶中干物质表现为先升高后下降,且营养液中高浓度的 Mg2+ 有利于干物质向叶中分配。4) 营养液中镁离子浓度小于 6 mmol/L 时,一定程度地提高 Mg2+ 浓度能促进对 K 的吸收,营养液中的 Mg2+ 和 K+ 在镁钾吸收上表现为协同作用,当 Mg2+ 大于 6 mmol/L 时,镁和钾表现为显著的拮抗作用;亚低温下,根茎叶的镁吸收量相比 CK 分别下降 25%、72% 和 58%,而营养液中 K+ 和 Mg2+ 均为 6 mmol/L 时,有利于缓解这一阻碍效果。【结论】冬春季黄瓜育苗时,山崎黄瓜配方营养液中的 Mg2+ 和 K+ 均为 6 mmol/L 而其他元素浓度保持不变时,黄瓜幼苗的壮苗指数、根系形态、干物质积累和钾镁元素综合效应表现较好,能有效地抵御亚低温对黄瓜幼苗的伤害。  相似文献   

16.
Effects of Al toxicity and interaction of Al and Mg on growth of twelve sorghum (Sorghum bicolor (L.) Moench) genotypes have been studied in nutrient solutions (pH 4.2). Aluminium at 30 μM decreased biomass (dry matter yield) of the individual genotypes by factors between 1.27 and 7.36, with identical sensitivity grouping of genotypes as obtained in an earlier pot experiment with an acid soil. Resembling acid-soil stress, Al toxicity was simultaneously expressed in two independent ways, i.e. impairment of root development and induced Mg deficiency. The effect of Al on total dry matter production of the genotypes was correlated more closely with changes in specific root length (m g−1 dry root) than with changes in internal Mg status. Increased Mg concentrations in the solutions (2.5 and 7.5 instead of 0.25 mM) not only decreased Al-induced Mg deficiency but also reduced the concentrations of Al in/on the roots and its damaging effect on root development. Therefore, the sorghum genotypes were less sensitive to Al at the higher Mg levels. At a high Mg concentration in the solution (7.5 mM) dry matter yield of two genotypes was even stimulated by Al.  相似文献   

17.
Despite the wide availability of liquid herbal extracts using mixtures of alcohol, glycerin, and water, or glycerin and water as solvents, no data on the chemical composition of such extracts is readily available. In this study, the amount and the stability of the major saponins in Panax quinquefolius root extracts, made either with 50% (v/v) aqueous ethanol, a mixture (v/v/v) of 20% ethanol, 40% glycerin, and 40% water, or with 65% (v/v) aqueous glycerin, were evaluated by HPLC-UV analysis. The amount of total saponins was highest in the 50% aqueous ethanol extract (61.7 +/- 0.1 mg/g dry root), although similar to the ethanol-glycerin-water extract (59.4 +/- 0.5 mg/g dry root). Saponins were significantly lower in the 65% aqueous glycerin extract (51.5 +/- 0.2 mg/g dry root). Interestingly, the amounts of individual saponins were quite variable depending on the solvent. This is in part due to enzymatic cleavage of ginsenosides in the glycerin containing extracts during the maceration process. Storage of the extracts at 25 degrees C over the period of a year led to a 13-15% loss of saponins with all three types of extractions.  相似文献   

18.
A validated mathematical model was used to simulate the effects of roots biomass and distribution on the water uptake of a 120-year old beech (Fagus silvatica L.) stand located at Solling (West Germany). The modell was based on the soil-water movement equation including an extraction term to account for the water uptake of the root system. This extraction term varies with the meteorological conditions, root density and soil water potential. Root biomass values considered were: 500 kg. ha?-1, 1000 kg. ha?-1, 2000 kg. ha?-1, 4000kg. ha?-1 and 6000 kg. ha?-1. For each of these values, five different distributions were tested. These ranged between a soil profile 0.40m deep with high root concentration to a 1.00m soil profile with idealized uniform root distribution. The model was run under two different rainfall conditions: i) an uncommon dry year (1971), (ii) a hypothetical normal year without a dry period. The model showed the fundamental importance of the root distribution under the given meteorological conditions. This was more evident when the root biomass was low and medium. A good root distribution throughout the profile allowed the forest to overcome long dry periods. With the maximum root biomass value the distribution had no effect on the forest water uptake.  相似文献   

19.
Low supply of nutrients is a major limitation of forage adaptation and production in acid soils of the tropics. A glasshouse study was conducted to find differences in plant growth, nutrient acquisition and use, among species of tropical forage grasses (with C4 pathway of photosynthesis) and legumes (with C3), when grown in two acid soils of contrasting texture and fertility. Twelve tropical forage legumes and seven tropical forage grasses were grown in sandy loam and clay loam Oxisols at low and high levels of soil fertility. After 83 days of growth, dry matter distribution among plant leaves, stems, and roots, leaf area production, shoot and root nutrient composition, shoot nutrient uptake, and nutrient use efficiency were measured. Soil type and fertility affected biomass production and dry matter partitioning between roots and shoots. The allocation of dry matter to root production was greater with low soil fertility, particularly in sandy loam. The grasses responded more than the legumes to increased soil fertility in both shoot and root biomass production. Leaf area production and the use of leaf biomass for leaf expansion (specific leaf area) were greater in legumes than in grasses, irrespective of soil type and fertility. But soil type affected shoot biomass production and nutrient uptake of the grasses more than those of the legumes. There were significant interspecific differences in terms of shoot nutrient uptake. The grasses were more efficient than legumes in nutrient use (grams of shoot biomass produced per gram of total nutrient uptake) particularly for nitrogen (N) and calcium (Ca).  相似文献   

20.
采用局部无菌水培方法,研究了氨基酸部分替代硝态氮对小白菜产量、品质及根际分泌物的影响。结果表明:与单一硝态氮处理相比,20%氨基酸部分替代硝态氮处理小白菜产量下降,硝酸盐及可溶性淀粉含量也显著降低,其中以20%谷氨酸（Glu）处理最低,分别为1490.8 mg/kg、1.77 mg/g;提高了小白菜全氮、可溶性蛋白、可溶性糖、游离氨基酸的含量,改变其根系形态结构及根系活力;同时,20%甘氨酸（Gly）、20%混合氨基酸(AAS）处理显著提高根系分泌物中铵态氮、游离氨基酸、总有机碳及总氮、可溶性蛋白的含量,根系分泌物中有机氮占总氮的百分比在Gly、Glu、AAS处理中分别提高了5.6%、11.2%、12.8%。表明氨基酸部分替代硝态氮可改善小白菜的品质,其生物量与各根系分泌物呈明显的负相关(0.7  相似文献   

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