太子参微块根发育的解剖学与组织化学定位

采用植物组织培养、解剖学及组织化学定位方法研究太子参试管微块根发育的形态结构与营养物质积累特征的结果表明：太子参微块根由组培苗膨大的腋芽基部长出的不定根发育而成,经历了初生结构与次生结构发育,其膨大加粗是由于不定根的次生生长。维管形成层向内形成大量的次生木质部构成微块根的主要部分。淀粉粒是太子参微块根的主要营养存储方式。随着微块根的次生生长,淀粉粒先在次生木质部薄壁细胞中形成,随后在次生韧皮薄壁细胞中也大量积累。膨大的微块根可以合成太子参皂苷,成熟微块根中次生韧皮部的皂苷含量略高于次生木质部。离体太子参微块根的生长发育和营养物质的积累与块根中的相同。     

麦冬与山麦冬块根形态发育的比较研究

采用石蜡切片法,对不同发育阶段的麦冬和山麦冬块根进行了显微观察,结果表明麦冬和山麦冬块根均是在不定根的根尖部位形成,其生长发育主要依靠皮层细胞层数的增加和皮层细胞体积的增大来实现,但在麦冬与山麦冬中,两者在块根膨大中所起的作用有所不同:皮层细胞层数的增加和皮层细胞体积的增大在麦冬块根膨大的过程中均起着重要作用,而在山麦冬块根膨大的过程中则以皮层细胞层数的增加为主,皮层细胞体积的增大为辅。     

栽培太子参块根的发育解剖学研究

应用石蜡制片技术研究了栽培太子参纺锤状块根的发育过程。结果表明,栽培太子参的块根是由其不定根发育而成。太子参不定根的初生结构与次生结构的发育可分为4个阶段:原分生组织阶段、初生分生组织阶段、初生结构与次生结构阶段,类似一般草本双子叶植物根的发育。其特点是初生结构的皮层细胞大,仅3 ~4层,内皮层细胞具凯氏带;初生木质部多为三原型,少数为二原型、四原型与五原型。次生结构中次生木质部约占根面积80 %,主要为薄壁组织细胞,导管呈稀疏的放射状分布其中。由不定根发育成块根过程中,根据从根头至根尾不同距离的各组成部分的面积及细胞层数分析,从上向下其维管形成层活动强度不同,从而根的直径大小不同,使根发育成上粗下细的纺锤状肉质块根。高碘酸-Schiff反应显示,在成熟的块根中次生韧皮部的薄壁组织细胞和次生木质部射线间的木薄壁组织细胞内富含淀粉粒,在有些木薄壁组织细胞中还含有草酸钙簇晶。     

怀地黄块根的形态发生和结构发育

观察了怀地黄(Rehmannia glutinosa cv．Hueichingensis Hsiao．)块根的形态发生和生长发育过程中的形态结构变化。采用怀地黄的传统栽培方法,即用上一年的块根作母根进行繁殖,分别从母根和不定芽的茎基部发生不定根。怀地黄不定根的初生结构和维管形成层的发生与一般双子叶植物相同,但其次生生长却有两种方式,即正常次生生长和异常次生生长。一类不定根的形成层产生的次生结构与一般双子叶植物相同,即次生木质部中主要是导管,而薄壁细胞较少。这类不定根其次生生长为正常次生生长(normal secondary growth),是担负吸收和固着作用的正常根。另一种类型的不定根,其形成层产生的次生木质部含有大量的薄壁细胞,少量的导管分散在薄壁细胞之间。这种次生生长为异常次生生长(anomalous secondary growth),从而使不定根膨大,形成块根。因此,怀地黄的药用部分在起源和结构上都属于根的性质,其药用部分应称为块根。     

甘薯块根膨大过程中ATP酶活性、ATP和ABA含量的变化

研究选用鲁薯7号和徐薯18号为材料,对甘薯块根膨大速率变化动态及其块根中可溶性碳水化合物含量、ATP含量、ATP酶活性和脱落酸（ABA）含量的变化进行了研究分析。结果表明：（1）块根膨大速率变化动态呈一双峰曲线,第一个高峰出现在栽秧后50－70d,第二个高峰出现在栽秧后120－165d;（2）块根膨大高峰期,块根中可溶性碳水化合物含量较高,ATP含量则较低;（3）块根中ATP酶活性和ABA含量变化动态与块根膨大速率变化动态相似。讨论了ATP酶和ABA在块根膨大过程中的可能作用。     

何首乌块根中异常结构的形成过程

何首乌的块根是一种常用的中药,块根内具有异常的次生结构。在块根的横切面上,自外至内依次为周皮、薄壁组织、排列成一圈大小不等的异常周韧维管束和中央维管柱。在块根形成以前,根的初生和次生结构都是正常的。以后,通常由围绕在初生韧皮纤维束周围的中柱鞘和次生韧皮薄壁组织细胞形成异常形成层,产生异常维管束。此外,还发现少数由中央维管柱分支而成。在块根膨大过程中,束内外以及维管柱次生木质部的薄壁组织细胞也分裂并增大。从而使块根中薄壁组织占80%左右。上述变化过程在不定根的中部开始,向上、下两     

太子参商品药材及其四倍体植株块根的高效液相指纹图谱

对不同产地太子参〔Pseudostellaria heterophylla(Miq.)Pax〕商品药材及其四倍体植株的块根进行了高效液相指纹图谱分析。结果表明,10个批次的不同产地太子参商品药材与经选育获得的6个株系太子参同源四倍体植株块根的HPLC-UV指纹图谱相似度较高,均在0.9以上。选取15个特征峰并大致判断其峰位和比例关系,构成太子参特有的HPLC色谱指纹图谱,为太子参药材鉴别、品质评价及优良品种的选育提供可靠依据。     

栽培太子参块根中皂苷的组织化学定位及其含量变化

应用植物解剖学、组织化学定位及植物化学技术,研究了栽培太子参块根不同发育时期的结构特征与皂苷积累的关系.结果表明:太子参不定根的初生结构和次生结构类似一般草本双子叶植物根的特征.在成熟的块根中次生木质部约占80%,其中以木薄壁组织细胞为主.导管很少,次生韧皮部中也以薄壁组织细胞居多,从而形成纺锤状块根.组织化学定位显示,在根的初生结构中,皂苷分布在中柱鞘和初生韧皮部的薄壁组织细胞中.在次生结构与成熟块根中,皂苷分布在除木栓层及导管外的周皮及次生维管组织其它细胞中,其中次生韧皮部显色较深.植物化学检测结果表明,2月与7月块根的皮部中皂苷的含量高于木部,与组织化学结果一致:根头部的皂苷含量＞根尾部＞根中部.在块根的发育过程中,皂苷的含量存在高一低一高的动态特点,此种变化规律与其根系的发育特点相关.     

太子参细胞悬浮培养及其皂苷含量分析

以太子参的幼叶为外植体,诱导培养获得太子参愈伤组织,并通过细胞悬浮培养获取皂苷.结果表明：用MS＋BA 0.2 mg L^-1＋2,4-D 1.0 mg L^-1＋KT 1.0 mgL^-1液体培养基可获得大量繁殖速度快、生长均匀一致的悬浮细胞.由细胞悬浮培养获得的太子参皂苷的HPLC色谱峰值与常规种植及组培苗的相同,但纯度较好.细胞悬浮培养约30 d时,每克干重细胞的培养液内可提取总皂苷量为2.13-2.92 mg,略低于大田常规种植所收获的每克干重太子参块根内的总皂苷含量（3.6-4.3 mg）,与组培苗收获的太子参块根内的总皂苷含量相近.     

伊乐藻和黑藻断枝根和芽的发生及生长研究

为了解外来种伊乐藻的无性繁殖力、评价其生态安全性,采用插植方式比较研究了伊乐藻(Elodea nuttallii)和本土种黑藻(Hydrilla verticillata)两种沉水植物不同节数(1至4节)和不同节位断枝的不定根和新芽的发生及生长情况。通过室内4周的3次平行实验,结果表明:两者顶芽段均有形成不定根继而形成新植株的能力,而顶芽以下茎段只有本身具有腋芽的断枝才有形成新芽和不定根的能力。两者具相同节数的断枝形成不定根的百分率及根、芽长度,以具顶芽断枝的均明显高于不具顶芽断枝的,具顶芽四节断枝的不定根生成率最高达到90%以上。不具顶芽断枝形成新芽和不定根的百分率及长度随着断枝节数的增加均呈显著递增趋势,每类断枝的发芽率显著大于其生根率;伊乐藻和黑藻枝条一般分别每7节和5节具有一个腋芽,只有具腋芽断枝才能存活,因此,对不具顶芽断枝,7节和5节分别是其形成新苗所需的最短断枝长度。根和芽的长度随节位的下降大致呈递增的趋势。但是节数对形成根、芽的影响显著大于节位的影响。具顶芽断枝的顶芽的增长量和具顶芽4节断枝的生物量增量伊乐藻的高于黑藻,其余指标伊乐藻均显著低于黑藻。伊乐藻断枝的繁殖力总体上低于黑藻。       

The Seasonal Dynamics of the Biomass of Vitex Shrubland in Mountainous Area of Huairou County in Beiiing

Vitex shrubland is a typical secondary shrubland in mountainous area of Huairou County and also in the low-mountainous area of north China. Over 80% of the biomass of the shrubland are contributed by its dominant species-Vitex negundo var. heterophylla. Due to frequent cutting, the aboveground biomass of Vitex shrubland was continually removed, and that of its underground accounts for 55% of the total biomass. In 1986, the primary net production of Vitex was 6363.6 kg·ha-1·a-1, in which 72.4% came from its roots, only 12.4% was contributed by the stems. The highest growth rate of the roots of Vitex appeared from May to July and the average productivity in this period was 49.7 kg·ha-1·d-1. The highest growth rate of stems with the average of 8.69 kg·ha-1·d-1 was found from July to October. Obviously, the photosynthetic products had firstly transported to the roots and were accumulated, and then transported to the stems. The allocation of photosynthetic products in the different parts of shrub organ showed that photosynthetic products were accumulated in ball root, then transport to other parts of roots. The top of stems was the first part where photosynthetic products were accumulated, then other parts of stems. A comparison with the biomass of other Vitex shrublands in the similar enviroment in Beijing area shows that biomass of the shrublands in north slope is larger than that in south slope. Comparing the biomass of Vitex shrubland with the biomasses of artificial forests in the same area with similar habitat we found that trees in the site occupied by the shrubs which we studied, can offer 5 times biomass than that of the shrubs.     

Influence of root temperature on uptake and accumulation of Ni and Co in potato

The impact of root temperature on Ni and Co concentration and accumulation has been studied in organs (roots, tubers, stems and leaves) of Solanum tuberosum L. var. Spunta plants. The response of foliar- and root-urease activity was also determined under the same conditions. Four different polyethylene plastic covers were employed (T1: transparent; T2: white; T3: coextruded black+white; T4: black), using uncovered plants as control (T0). The different treatments had a significant effect on mean root zone temperatures (T0 = 16 °C, T1 = 20 °C, T2 = 23 °C, T3 = 27 °C and T4 = 30 °C) and induced a significantly different response in the Ni and Co distribution in potato organs, since T3 (27 °C) gave higher concentrations of Ni in roots, leaves and tubers. The T1 (20 °C) registered the greatest Co concentration in leaves and roots, while T3 gave higher Co concentrations in tubers. The tubers proved to be the organs with the highest biomass and also the highest Co and Ni accumulation. With respect to the response of the urease activity as Ni-bioindicator, the root urease activity was higher in T1, whereas the leaf urease activity was higher in T3 and T4, coinciding with higher concentrations of leaf Ni. It is necessary to ascertain the relevance and control of the thermal regime of the soil to optimize the phytoextraction (phytoremediation) of elements.     

水曲柳根系生物量、比根长和根长密度的分布格局

采用连续钻取土芯法在生长季内对东北林业大学帽儿山实验林场17年生水曲柳人工林根系取样,研究水曲柳不同直径根系现存生物量、比根长和根长密度及垂直分布状况.结果表明,水曲柳人工林根系总生物量为1 637.6 g·m^-2,其中活根生物量占85%,死根占15%.在活根生物量当中,粗根(直径5～30 mm)占的比例最高（69.95%）,其次为活细根（直径<1 mm,13.53%）,小根(1～2 mm)和中等直径的根(2～5 mm)比例较小（分别为7.21%和9.31%）.直径<1 mm活细根的比根长为32.20 m·g^-1,直径5～30 mm粗根的比根长为0.08 m·g^-1.单位面积上活根的总长度为6 602.54 m·m^-2,其中直径<1 mm的细根占92.43%,其它直径等级则不到活根总长度的8%.直径<1 mm的细根生物量与根长密度具显著线性关系（R²=0.923）,但与比根长无显著相关关系（R²=0.134）.     

Investigating the in vivo calcium transport path to developing potato tuber using 45Ca: a new concept in potato tuber calcium nutrition

Calcium is believed to be transported with water in the xylem. Consistent with this proposal, low‐transpiring organs such as potato Solanum tuberosum tubers are known to suffer from calcium deficiency. Although roots on tubers and stolons have been shown to supply water to tubers, there is no direct evidence for the calcium transport pathway to tubers. Both a xylem and a phloem transport pathway have been suggested. We investigated in vivo calcium transport to developing potato, cv. Dark Red Norland and cv. Russet Burbank, tubers using ⁴⁵Ca in a controlled environment facility. Whole plant split pot experiments allowed the placement of ⁴⁵Ca either in the main (basal) root or the tuber and stolon areas of the pot. The results showed that ⁴⁵Ca was transported to the shoot with the transpiration stream from both areas but was not re‐translocated to tubers or the main (basal) root system even 57 days after ⁴⁵Ca application. Radioactivity could only be detected in the tuber when ⁴⁵Ca was fed to the stolon and tuber area. When ⁴⁵Ca was fed to specific tubers, radioactivity was detected in the aerial shoot; however, no activity was detected in other tubers or the main (basal) roots. In another set of experiments, roots on a stolon near a tuber were precisely fed ⁴⁵Ca and Safranin O. The radioactive signal exactly overlapped the water transport pathway in the tuber marked with Safranin O dye, suggesting that water and calcium can be simultaneously transported from stolon roots to the tuber. No transport of ⁴⁵Ca across the tuber periderm was detected 8 days after ⁴⁵Ca was applied to the tuber periderm. This indicated that no significant transport of calcium occurs from the soil across the periderm. Our results provide evidence that: (1) calcium is not re‐translocated via the phloem from the aerial shoot tubers and main (basal) roots; (2) the main root system does not supply calcium to the tuber; (3) calcium is not transported across the periderm to the interior tuber tissue; (4) calcium is transported to the tuber via the xylem along with water, and the roots on the stolon associated with the tuber supply water and calcium to the developing tuber; and (5) transpirational demand is a significant determinant of calcium distribution within the plant.     

Growth of the Tops of Sweet Potato and the Translocation of the Nutrients from Leaves

1. Experiments were carried out in Hangchow on the increase of dry matter in the tops of sweet potato plants. The increase can be divided into three periods: (1) slow accumulation of dry matter; (2) rapid increase of accumulation of dry matter, reaching a maximum; (3) decline of accumulation of dry matter, later on account of senility and the dropping of leaves, there was a marked reduction in the dry matter of the tops. The increase in dry matter is in proportion to the leaf area. The amount of fertilizer used is closely related to the increase of dry matter and leaf area. 2. The yield of sweet potato is related to the increase in dry matter of the tops of the plant. To a certain extent, the greater the amount of dry matter, the more rapidly will the tubers enlarge, finally results in a higher yield. Excessive use of fertilizer leads to an abnormal elongation of the plant. During this period an increase in dry matter of the tops not only fails to induce the enlargement of the tubers, but also leads to the consumption of the dry matter, and consequently causes a reduction in yield of sweet potato. From the curve of T/R ratio, the sooner the downward translocation of the tops nutrients occurs, the faster the tubers will form and enlarge. 3. Experiments with p32 show that the various growth conditions of the tops are closely correlated with the translocation of the tubers. With well growing and high yielding plants the nutrients move from the tops to the tubers as soon as the root enlarges. This translocation is even accelerated during the later stage. During the earlier stage of development, much of the plant nutrition is translocated to the stems and leaves, particularly to the latter; then gradually it is diverted to the leaves and the root system, and finally concentrates in the roots. The increase of the area of green leaves and the number of branches during the period of early growth, and the promoting of favourable conditions for the formation and enlargement of the roots, as well as the facilitating of the translocation of nutrients to the roots during the later stage are the determinative factors necessary for obtaining high yield of sweet potato.     

褪黑素对水稻镉积累及其化学结合形态的影响

研究了添加外源褪黑素对水稻幼苗中Cd积累以及水稻体内Cd化学形态分布的影响.结果表明: Cd胁迫显著降低水稻幼苗地上部和根部的生物量,并且显著降低水稻叶片的叶绿素含量.适宜的外源褪黑素添加能明显提高Cd胁迫下水稻的地上部和根部生物量,降低水稻地上部和根部Cd含量.当Cd胁迫浓度为5 μmol·L^-1时,添加20 μmol·L^-1褪黑素使水稻地上部和根部Cd含量分别比对照处理降低48.4%和16.9%,添加100 μmol·L^-1褪黑素水稻地上部和根部Cd含量分别降低67.5%和47.9%.添加外源褪黑素也显著降低了水稻体内Cd的转运效率.当Cd胁迫浓度为20 μmol·L^-1时,添加20 和100 μmol·L^-1褪黑素使水稻Cd的转运效率分别比对照降低24.4%和46.8%.通过逐步提取法对水稻幼苗Cd的化学结合形态进行分析发现,添加外源褪黑素使水稻体内氯化钠提取态Cd的比例提高,而水溶态Cd、乙醇提取态Cd的比例明显降低,说明添加褪黑素可促进水稻体内移动性较强的Cd形态向移动性较弱的Cd形态转移,从而降低水稻对Cd的吸收和转运.     

细根对竹林-阔叶林界面两侧土壤养分异质性形成的贡献

土壤养分异质性是竹林-阔叶林界面(bamboo and broad-leaved forest interface, 以下简称竹阔界面)的重要特征, 细根生长、周转和分解影响土壤养分供应能力, 但其在竹阔界面养分异质性形成中的贡献尚不清楚。该文选取竹阔界面两侧的毛竹(Phyllostachys pubescens)林和常绿阔叶林为研究对象, 开展土壤养分(C、N、P)含量、细根生物量及周转、细根分解及养分回归等指标的对比研究。结果表明: (1)竹阔界面两侧毛竹林和常绿阔叶林土壤养分差异明显, 毛竹林0-60 cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为20.51和0.53 g·kg^-1, 常绿阔叶林0-60 cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为13.42和0.26 g·kg^-1, 前者比后者分别高出34.53%和50.35%, 但毛竹林土壤全磷(STP)含量低于常绿阔叶林25.54%; (2)竹阔界面两侧细根生物量、养分密度及养分回归量差异明显, 毛竹林细根生物量高达1201.60 g·m^-2, 是常绿阔叶林的5.86倍; 养分密度分别为591.42 g C·m^-2、5.44 g N·m^-2、0.25 g P·m^-2, 分别是常绿阔叶林的6.12倍、3.77倍和3.11倍; 年均养分回归量分别为278.54 g C·m^-2·a^-1、2.36 g N·m^-2·a^-1、0.11 g P·m^-2·a^-1, 是常绿阔叶林的6.93倍、4.29倍和3.67倍; (3)细根对界面两侧土壤SOC、STN异质性形成的年均潜在贡献分别为76.79%和28.33%, 但对STP异质性形成起减缓作用, 贡献率为6.17%。这些结果说明毛竹扩张可以改变常绿阔叶林土壤的养分状况, 且细根对不同养分的异质性形成贡献不一致, 是土壤SOC、STN异质性形成的重要原因。