不同耕作方式棉花根系发育能力的研究

研究了不同耕作方式棉花根系的发育能力。结果表明,根系生物量、根系体积、侧根数在不同耕作方式间差异明显,在土壤中表现为从表层到深层逐渐递减。免耕方式根系分布较浅,主要集中在0~10 cm土层,而翻耕方式根系主要分布在10~20 cm土层。侧根的发生部位受不同深度土壤含水量的影响,侧根发生的主要部位在0~20 cm的主根段,40 cm以下没有侧根发生。     

低磷条件下植物根系形态反应及其调控机制

磷是植物必需营养元素之一,土壤中磷有效性低,限制作物生长发育。磷肥施用量逐年增加,但是磷矿资源面临耗竭。植物根系形态变化对于植物适应低磷胁迫,提高植物对土壤磷的吸收利用具有重要意义。本文从植物根系构型、根冠比、初生根、根毛、侧根等方面综述了植物适应低磷胁迫的根系形态变化特征。低磷条件下,植物根系构型发生改变,普遍抑制主根生长,刺激侧根发育起始与伸长,诱导根毛形成。同时,分析了转录因子、植物激素、蔗糖以及关键基因等对低磷条件下植物根系生长发育的生理与分子调控机制,低磷胁迫下转录因子ZAT6和MYB62参与调控初生根生长,BHLH32和PHR调控根毛形成发育,WRKY75对侧根发育有抑制作用。研究表明,在低磷条件下,赤霉素、细胞分裂素、生长素和乙烯对初生根发育起着调控作用,而根毛的生长发育与赤霉素、生长素和乙烯有关,侧根发育过程中生长素作用明显。一些基因如LPR1、LPR2、LPR3以及PDR2参与调控低磷胁迫下植物初生根的发育。低磷胁迫下光合产物蔗糖对植物根毛和侧根发育有影响。     

氮肥施用量对高产甜菜纤维根系分布及活力的影响

为了解施N肥对甜菜生长的影响规律。在田间条件下,研究了不同施N量（0、90、180、270、360 kg/hm2）对甜菜（KWS2409）纤维根系生长、分布和活力变化的影响。结果表明,施N比对照增加浅层侧根数、外层和深层纤维根干重及100 cm土层纤维根总干重,并提高各生育期侧根和主根活力。其中,100 cm土层最大纤维根干重施N 比对照增加了60.4%～168.4%,最大侧根数增加了22.7%～75.1%,且以0—20 cm和40—60 cm深的外土层及80—100 cm深的内土层纤维根系增加较大,分别比对照增加了129.6%～266.8%、71.0%～234.0%和101.5%～202.8%。主根伤流液量和侧根的活力分别比对照增加了56.2%～89.9%、23.7%～63.4%。N 180 kg/hm2处理0—100 cm土层中纤维根总量、各土层中根量最大,各生育时期主根和侧根活力最强,块根产量（82609.63 kg/hm2）和产糖量（13892.64 kg/hm2）均最高,而含糖率（16.83%）较N0处理（18.34%）略降。说明合理施N量有利于甜菜纤维根系生长和提高产糖量。     

种基盘苗与营养钵苗根系生长和形态的差异

为了探明苗木培育方式与根系发育的关系,以侧柏、刺槐、白榆的幼苗为对象,研究种基盘苗与营养钵苗对幼苗根系形态的影响。结果表明：由于空气断根效应,种基盘苗抑制了侧柏和白榆主根的生长,促进了刺槐主根的生长,但种基盘能有效促进3个树种的主根沿着重力方向生长,使主根发达而且通直,侧根粗壮且分布比较均匀,营养钵苗的根系主根不明显,根系盘绕现象严重;侧柏和白榆2树种种基盘苗的一级侧根条数分别比其营养钵苗增加181.8%和128.6%,并能显著增加白榆种基盘苗的一级侧根直径;侧柏、刺槐和白榆种基盘苗的一级侧根均匀分布在1-2、2-3、3-4和4-5 cm 4个区间,而营养钵苗则集中分布在1-2和2-3 cm 2个区间;种基盘可以促进苗木一级侧根条数增加和均匀分布,对提高苗木吸收水肥能力和保土固土能力有着积极的作用。     

干旱胁迫对白菜型冬油菜幼苗生理及农艺性状的影响

通过旱棚盆栽试验,以4个抗旱性不同的白菜型冬油菜品种陇油6号、陇油7号、天油2号、天油4号为材料,用人工控制浇水的方法模拟干旱环境,测定干旱胁迫对其生理生化指标、主要农艺性状的影响。结果表明,随着干旱胁迫时间的延长,4个油菜品种的幼苗叶片叶绿素质量浓度呈现先增加后降低的趋势,相对电导率增大,根系的主根长、侧根数、根系干重、根冠比上升,根系活力下降。干旱胁迫后,抗旱性强的冬油菜品种陇油7号主根长,侧根数多,根干重较重,根冠比大,根系活力稳定;弱抗旱冬油菜品种天油2号主根较短,侧根数少,根干重轻,根冠比小,根系活力变化幅度较大;中抗旱冬油菜品种陇油6号、天油4号各指标居于陇油7号和天油2号之间。     

不同基质对平邑甜茶幼树生长、根系形态与营养吸收的影响

采用盆栽方式,探讨了栽培于腐熟羊粪、沙土、轻粘土中的平邑甜茶[Malus hupehensis(Pamp) Rehd] 幼树的生长、根系形态与营养吸收的特性。结果显示,羊粪处理平邑甜茶幼树新梢生长量最大,主根和侧根粗长、侧根多,对磷、钙及铁的吸收能力较低;沙土处理的新梢生长量最小,侧根细及少,对磷、钾、钙、铁及锌等元素的吸收能力强;粘土处理的新梢生长量和根系特征参数居于羊粪和沙土处理之间。沙土施羊粪后,平邑甜茶幼树新梢生长量增大,主根增粗、增长,侧根增多且粗长,对磷、钾、钙、铁及锌等营养元素的吸收能力明显下降;而粘土施羊粪,植株叶片增多,主根粗度及长度降低,二级侧根增多、增粗,对钾的吸收能力提高。     

青藏高原东北部4种灌木主根和侧根抗拉力学特性比较

[目的]开展青藏高原东北部黄土区4种灌木植物主根和侧根抗拉力学强度试验,探讨主根和侧根抗拉力学特性关系,为深入研究植物根系固土护坡力学机理提供参考。[方法]选取西宁盆地长岭沟流域作为研究区,对生长期为3 a的柠条锦鸡儿(Caragana korshinskii)、中宁枸杞(Lycium chinense)、白刺(Nitraria tangutorum)和霸王(Sarcozygium xanthoxylon)4种优势灌木主根和侧根进行室内单根拉伸试验,确定其主根和侧根抗拉力、抗拉强度和杨氏模量及其与根径之间的关系;在此基础上,进一步分析了4种灌木主根和侧根根径、抗拉力、抗拉强度和杨氏模量之间的关系。[结果]柠条锦鸡儿、中宁枸杞、白刺和霸王主根抗拉力分别为侧根的28.45,13.21,11.01,7.35倍,主根抗拉强度分别为侧根的0.67,1.17,0.68,1.22倍,主根杨氏模量分别为侧根的2.00,2.39,2.82,2.48倍。[结论] 4种灌木植物主根抗拉力均显著大于侧根;柠条锦鸡儿和白刺主根抗拉强度小于侧根,而中宁枸杞和霸王主根抗拉强度大于侧根;4种灌木植物主根杨氏模量显著大于侧根,说明其主根相对于侧根不易发生形变,对边坡浅层稳定性贡献亦显著于侧根。     

西洋参产量构成与同化产物的有效分配

利用14 C示踪技术研究了不同参龄各主要生育期同化产物的运转动态及对产量的关系 ,揭示了不同生育期同化产物转化为能量、结构物质和贮藏性物质的相对消长规律。结果表明 :3年生西洋参不同生育期14 C 同化产物向根运输快于向果运输 ,根是西洋参最强的同化产物竞争库 ,果实次之 ;4年生西洋参各主要生育阶段同化产物在生长、呼吸及贮存间的分配比例不同 ,展叶期的同化产物 85 %以上用于后续生长的能量代谢和器官建造 ,收获期参根中 80 %的干物质来源于花期以后的同化产物     

鲱骨状根构型对典型土体抗倾覆力的有限元分析

 设计和实施治理重力侵蚀的生物工程措施需要深入地分析和研究树木根系对土体的抗倾覆力学特性。本文以单株鲱骨（Herringbone）状根构型为研究对象建立二维有限元模型,通过控制侧根与主根的夹角、删减根系不同部分等方法,建立了12种不同几何形态的鲱骨状根结构,并分别验证其在黏土和砂土中的抗倾覆力,由此定量评价根系的不同部分和土壤的差异分别对土体抗倾覆力的贡献率。模拟结果显示:浅层侧根的作用是不可低估的,在黏土中,其贡献率约占整个固土效果的35%40%;根、土复合体在整个破坏过程中形成一个旋转轴,此轴的位置随根系形态、土壤类型的不同而变化。     

高铵胁迫对拟南芥根系向重性的影响及机制初探

向重性是决定植物根系构型的主要因素之一,对根系锚定及水分养分吸收具有重要影响.铵显著影响拟南芥根构型,尽管高铵抑制主根伸长和侧根数,然而铵对主根生长方向的研究却少有报道.本文以拟南芥为材料,利用室内培养基模拟试验,研究了高铵胁迫对根系向重性生长的影响,发现高铵胁迫不仅抑制植物生长,还影响主根的生长方向.0～30h动态观测结果表明:10 mmol/L (NH4)2SO4对根系的向重性反应仅表现为延缓效应,而30 mmol/L(NH4)2SO4则显著减弱主根的向重性弯曲.降低基本培养基养分浓度后,铵对主根向重性反应的抑制效应可发生在较低的NH4+浓度.外源添加Ca2+可部分恢复铵对主根伸长的抑制效应,却不能缓解铵对主根向重性反应的影响.不同部位分开供铵,结果显示铵对拟南芥主根向重性的影响主要是根部铵效应.上述结果表明,铵对主根向重性的影响机制部分独立于其对主根伸长的影响,也不是由于Ca2+缺乏引起的,而有可能与根部高铵诱导的根尖其他生理活动过程改变有关.     

Influence of zinc on the growth,distribution of elements,and metabolism of one‐year old American ginseng plants

Using a water culture technique, 0.05 ppm zinc (Zn) was found to be the critical deficiency concentraction for one‐year American ginseng (Panax quinquefolium L) plants, 0.3 ppm was optimum, 0.5 ppm the critical Zn‐toxicity concentration, and 10 ppm the concentration when severe toxicity occurs. Therefore, the optimum Zn concentration for the growth of American ginseng plants was between 0.1 ppm ‐ 0.3 ppm. Zinc deficiency symptoms of one‐year old American ginseng plants were indicated by the inhabition of root growth, with little fibrous root development, and smaller leaves compared to normal leaves. The symptoms of toxicity were also indicated by the inhibition of root growth, and when seedlings were suffering from an acute toxicity, no fibrous roots appeared, and eventually the roots yellowed and leaves grew slowly or even entirely ceased to grow, the final result being very small leaves which are also chlorotic. Zinc maintained within the 0.1 ppm to 0.3 ppm sufficiency range promoted the synthesis and accumulation of ginsenosides by American ginseng plants, and both low and high Zn concentrations restrained the synthesis and accumulation of ginsenosides. Both Zn deficiency and the optimum Zn concentration (0.3ppm) are beneficial to the accumulation of amino acids in the roots of American ginseng plants. Close to the optimum Zn concentration, the ratios of P/Zn and Fe/Zn in the shoot of American ginseng plants were maintained at 77 and 9.4, respectively.     

甘蓝根茎切割力影响因素分析

为了合理设计4YB-1型甘蓝收获机切割装置,使其对甘蓝根切割效果更好.该文在微机控制多功能试验机上,进行单因素和多因素正交试验,研究了切割方式、切割刀片形式、切割速度和切割位置对甘蓝根茎切割力的影响.结果表明,切割位置对切割力的影响最大,切割力随着切割位置接近甘蓝顶层叶而减小,较优的切割位置距顶层着叶5~40 mm处,根径为22~30 mm用锯齿刀滑切时能大大降低甘蓝根茎的切割力;切割力随着切割速度的增加而减小,切割速度为150 mm/min 时有利于顺利切割,此时最大切割力为97.8 N;甘蓝根茎切割采用锯齿刀、滑切方式为宜.研究结果为4YB-I型甘蓝收获机切割器的设计和安装提供了理论依据.     

Translocation and distribution of assimilated carbon in peanut plant

An attempt was made to monitor ¹³C that had been photosynthetically assimilated in the foliage of the main stem and branches of peanut plant, as well as in a single leaf at different positions on a branch.

When the foliage of the main stem or branch was supplied with ¹³CO₂ for 8 h at the vegetative stage, ¹³C assimilated in the branches was detected in the roots and nodules in addition to the foliage immediately after the exposure, whereas when the main stem was supplied with ¹³CO₂, ¹³C was not detected in the roots and nodules immediately after ¹³CO₂ feeding. At the reproductive stage, ¹³C assimilated in the main stem or branch was found in the leaves, stems, fruit (shell, seed coat, and seed), roots, and nodules immediately after assimilation.

Photoassimilates from each leaf of the branch at the reproductive stage were exported to the fruit and leaves that were attached to the same branch. Namely, photoassimilates in the leaves of odd nodes were mainly translocated to the fruits attached to the first node, whereas such photoassimilates from the leaf of even nodes were mainly translocated to the fruit attached to the second node.

When the foliage of a branch had been fed ¹³CO₂ at the vegetative stage, the loss of the assimilated ¹³C by respiration was about 40% of the total assimilated ¹³C within 23 d and about 65% within 93 d after the exposure, and a small amount of photoassimilates was detected in the fruit. On the other hand, at the seed-filling stage, about 35% of the photoassimilates were utilized for seed growth within 10 d after the end of exposure.

These results suggest that in the peanut plant, the carbon source of nodules mainly depends on the branch, and the main stem plays an important role as carbon source for the fruit, that a sink organ for carbon is connected with a specific sources leaf by the vascular bundles, and that most of the carbon sources for the growth of peanut fruit depend on the photoassimilates at the reproductive stage.     

Saponins composition in American ginseng leaf and berry assayed by high-performance liquid chromatography

The root of American ginseng is a commonly used herbal medicine in the United States. However, the compositions of American ginseng leaves and berries are not clear to date. In this study, we improved a method for the analysis of 12 ginsenosides based on solid phase extraction and high-performance liquid chromatography-ultraviolet. Good resolution was obtained for all tested ginsenosides: Rb1, Rb2, Rb3, Rc, Rd, Re, Rg1, Rg2, 20(R)-Rg2, Rg3, Rh1, and Rh2. Ginsenosides Rh1, Rg2, and 20(R)-Rg2 were easily separated with this column. The modified gradient elution program resulted in satisfactory linearity and precision. Solid phase extraction made the analysis accurate and efficient. Other investigators recently observed that ginsenoside Rb3 is a potent neuroprotective compound; it can promote learning and memory. In this report, we found that the major ginsenoside in American ginseng leaves and berries was ginsenoside Rb3, while Rb3 only had limited amounts in the root of American ginseng and other species of the Panax genus. Ginsenoside Rb3 was quantified as 4.71% in American ginseng leaves and 5.35% in berries, suggesting that American ginseng leaves and berries are new sources of ginsenoside Rb3.     

喷施矮壮素和多效唑对紫云英生长发育及结实性状的影响

  【目的】  研究不同时期喷施矮壮素和多效唑对紫云英生长发育及结实的影响，明确有利于增产的最佳喷施时期，为提高紫云英种子产量提供有效的化控途径。  【方法】  选取紫云英品种‘信紫1号’为供试材料，分别于越冬后期、返青期、现蕾期、初花期和始花后5天在叶面喷施矮壮素或多效唑 (浓度均为400 mg/kg)，以叶面喷施清水为对照。于盛花期，调查株高、茎粗、分枝数、SPAD值、单株重等生长指标，成熟期按常规考种法考察记载花数、荚数、籽粒数、结荚率和荚果结实率等结实性指标。  【结果】  现蕾期叶面喷施矮壮素和多效唑均可有效抑制植株株高，提高分枝数、SPAD值和单株重，多效唑喷施效果好于矮壮素。与喷清水对照相比，现蕾期喷施矮壮素的紫云英花数、荚数、籽粒数、结荚率和荚果结实率分别显著提高了16.32%、21.45%、15.94%、2.38个百分点和0.94个百分点，而其在越冬后期和返青期喷施却显著降低各指标；现蕾期喷施多效唑的紫云英花数、荚数、籽粒数、结荚率和荚果结实率分别显著提高了31.69%、43.41%、29.49%、4.76个百分点和2.14个百分点，在越冬后期喷施显著降低花数和荚果结实率。矮壮素和多效唑均在现蕾期喷施的种子产量最高，两者较对照分别增产15.95%和29.88%。  【结论】  在紫云英现蕾期，叶面喷施植物延缓剂多效唑和矮壮素，均可显著促进花期花荚发育，减少花荚脱落，促进花荚结实成粒，最终获得较高的种子产量，多效唑效果好于矮壮素。     

千层金嫩枝扦插繁殖技术

本研究用L16（45）正交试验方法,研究了基质、穗条长度、植物生长调节剂及其浓度对千层金嫩枝扦插生根率的影响。结果表明,基质和生长调节物质对生根率有极显著的影响,而植物生长调节剂浓度与穗条长度对生根率有显著的影响,4个因素对千层金嫩枝大田扦插生根率影响从大到小分别是基质、生长调节物质、植物生长调节剂浓度和穗条长度。用浓度100mg/L的NAA浸泡9cm插穗2h,在混和基质上扦插,平均生根率可达92%,且生根及新梢抽出时间早,侧根数量多,扦插效果最好。     

西洋参分段式热风干燥动力学模型构建

针对直接将干燥时间带入干燥动力学模型无法准确得到分段式干燥各干燥阶段水分比的问题,提出了一种适用于分段式干燥的干燥动力学模型计算方法,可用于分析分段式干燥过程中水分比变化规律。对西洋参进行了干燥试验研究并对试验结果进行了非线性拟合,表明Modified Page模型适用于西洋参热风干燥的干燥动力学;通过对干燥条件和干燥常数的线性回归分析得到了偏回归系数,基于该偏回归系数对西洋参分段式干燥过程进行分析,得到了西洋参分段式热风干燥中各段的干燥动力学模型。利用所提出的计算方法对西洋参分段式干燥过程中水分比变化情况进行了计算,并将计算结果与西洋参分段式热风干燥试验结果进行了对比分析,发现计算结果与试验结果最大相对误差为7.44%,平均相对误差仅为1.78%。表明所提出的分段式干燥动力学模型计算方法可用于分析西洋参干燥过程中的水分比变化。     

MET对大豆群体发育及光合产物分配的影响

MET(Multi-Effect Triazole,多效唑)是一种新型植物生长延缓物质,在大豆始花期喷施200ppmMET,使植株个体矮壮紧凑,群体封行推迟,并提高了株间的透光率;同时,MET处理,使单株同化~(14)CO_2量显著增加,越接近成熟期喂饲~(14)CO_2,同化物向籽粒中运输的越多。MET处理对~(14)C同化物运砖的调节作用,主要表现在增加~(14)C同化物向根系及籽粒的运转。     

沙棘根系的生物学特性与造林地选择

沙棘有很强的根蘖能力,其根系具有类似水生植物根系的解剖特征,地上部分又有旱生植物的特征,所以沙棘应属中生植物;沙棘根系有很强的生物学可塑性,对林地的水分状况会产生明显反应;在植株个体发育早期,多在生长较慢的侧根上形成具有多种功能的根瘤。沙棘造林,应充分考虑其根系生物学特性和解剖特征,根据经营目的选择相应的造林地或采取整地措施改地适树,满足其水分要求。