净化污水植物香蒲形态解剖特征的比较研究

用高浓度铅锌废水和清洁水中生长的香蒲Typha latifolia 为材料,制片供显微观察,进行形态解剖特征的比较研究。结果表明:生活在铅锌废水中的香蒲叶表皮细胞变小变方形,出现质壁分离。叶绿体的数量减少,而气孔的数量增加。     

EFFECTS OF WATER DEPTH ON TYPHA LATIFOLIA AND TYPHA DOMINGENSIS

The two species of Typha common in the southeastern United States, T. latifolia and T. domingensis differ substantially in their tolerance to deep water. The objective of this study was to examine the morphology and biomass allocation of these two species to determine if they have similar phenotypic responses to water depth. Replicate monocultures of the two species were established at a range of water depths in an artificial pond and allowed to grow for three growing seasons. At the end of the experiment, subsamples were harvested for determination of plant morphology as well as above- and belowground biomass. Both species of Typha showed increases in maximum height with increasing depth. The species less tolerant to deep water (T. latifolia) allocated more of its biomass to leaves with increasing water depth. In contrast, the deep water species (T. domingensis) showed increased total size of each ramet but a fixed percentage of biomass in leaves with increasing water depth. Both species had a decreasing incidence of flowering and decreasing shoot density with increasing water depth. In general, these species conform to expectations based on considerations of how their carbon budgets would be affected by water depth.     

ORIGIN AND DEVELOPMENT OF LATERAL ROOTS IN TYPHA GLAUCA

Lateral roots of Typha glauca arose from the pericycle of the parent adventitious root. Periclinal divisions of the pericycle gave rise to two layers; the outermost initially produced the ground meristem and protoderm, and the innermost produced the procambium. The immature endodermis of the parent root contributed to the early stages of the root tip as an endodermal covering. Prior to emergence, the ground meristem/protoderm produced cells into the endodermal covering. After emergence, the endodermal covering was replaced by a calyptrogen, which was derived from the ground meristem/protoderm and which, in turn, formed the rootcap. A typical monocotyledonous three-tiered meristem was then produced. An outer ground meristem also arose before emergence to form a hypodermis in many lateral roots; in these, crystalliferous cell production began in midcortex cells before emergence, and a small aerenchyma developed in their cortices. The rootcap columella stored small amounts of starch shortly after emergence. Lateral roots of T. glauca were smaller than their parental adventitious roots; they normally had only two to six poles of xylem and phloem, and the cortex was less than six cells across. During 1–3-cm elongation, the lateral root apical meristem and mature regions narrowed, stored starch disappeared, fewer crystals formed, aerenchyma production ceased, and the roots stopped elongation.     

铅锌矿废水中重金属在宽叶香蒲（Typha latifolia）的积累与分布

 本文通过对净化塘系统和对照点的水、土和宽叶香蒲组织的分析结果指出：宽叶香蒲具有较强的忍耐、吸收和积累Pb、Zn等重金属的能力。Pb、Zn等重金属在宽叶香蒲体内的积累数量与分布规律是根>地下茎>叶;老地下茎>嫩地下茎;Pb在叶的分布是老叶>成熟叶>嫩叶。在净化塘系统内,各种重金属在宽叶香蒲根部积累比例最大的是Pb,其次是Zn、Cu、Cd、Ni、Mn。     

GENETIC AND ENVIRONMENTAL CONTROL OF GLYCOLIC ACID OXIDASE ACTIVITY IN ECOTYPIC POPULATIONS OF TYPHA LATIFOLIA

Glycolic acid oxidase activity at 25 C in leaf homogenates of ecotypic populations of Typha latifolia varied according to native climate of the population and current growing conditions. Activity of plants grown under warm/short day conditions was positively correlated with maximum summer temperature at the site of population origin. Activity of plants grown under cool/ long day conditions was negatively correlated with length of growing season at the site of origin. Populations from sites characterized by a long growing season are much less susceptible to environmental regulation of enzymic level than populations originating in short growing season sites. Enzyme activity is not a secondary reflection of differentiation at the level of chlorophyll or cofactor concentration. Enzymic differences between ecotypic populations reflect differences in control systems at the level of protein synthesis and genetic structure.     

CHANGES IN STARCH DISTRIBUTION IN THE OVERWINTERING ORGANS OF TYPHA LATIFOLIA (TYPHACEAE)

Histochemical determinations for storage of carbohydrates in rhizomes, roots, and young shoots of Typha latifolia L. (Typhaceae) were conducted during the overwintering period from November to April. Early winter analysis showed that rhizomes and roots contained large amounts of starch (45.03% and 22.80% dry weight, respectively). The major storage tissue was parenchyma of the rhizome central core. From winter into spring a gradual decrease in storage starch in the rhizome and root occurred concurrently with starch accumulation near zones of rapid development in young shoots (buds), but the rhizome retained much starch (27.40% dry weight) into the start of its 2nd yr.     

NITROGEN FIXATION ASSOCIATED WITH NATURAL AND CULTIVATED STANDS OF TYPHA LATIFOLIA L. (TYPHACEAE)

Acetylene reduction by bacteria associated with Typha latifolia L. roots and rhizomes was studied in the field and in the laboratory. In situ studies indicated that the rate of acetylene reduction in a natural cattail population was ca. 4-fold higher than in a cultivated cattail stand. Nitrogenase activity was found to occur principally in the rhizosphere of roots and rhizomes with the greatest activity occurring in association with mature roots. Scanning electron and light microscopy, and 2, 3, 5 triphenyltetrazolium chloride reduction showed that bacterial associations were limited to the rhizoplane of this angiosperm. One diazotrophic bacterial genus was found to be associated with roots and rhizomes and was identified as the facultative anaerobe Bacillus. Contribution of free-living cyanobacteria to total nitrogen fixation in the natural stand was negligible. Calculations show that a natural stand of cattails may fix 18 kg nitrogen ha^−-1 yr^−-1 or ca. 8.2% of the total nitrogen present in the standing crop.     

蒙古香蒲,宽叶香蒲和长苞香蒲花粉的黄酮类化合物的研究

蒙古香蒲(Typha davidiana Hand.-Mazz.)宽叶香蒲(Typha latifolia L.)和长苞香蒲(Typha angustata Bory et Chaub)的干燥花粉中分别分离得到柚皮素(Ⅰ),异鼠李素(Ⅱ),檞皮素(Ⅲ),异鼠李素-3-O-(2~G-α-L-鼠李糖基)-芸香糖甙(Ⅳ),檞皮素-3-O-(2~G-α-L-鼠李糖基)-芸香糖甙(Ⅴ),异鼠李素-3-O-芸香糖甙(Ⅵ),异鼠李素-3-O-新橙皮糖甙(Ⅶ)和山奈酚-3-O-新橙皮糖甙(Ⅷ)。     

珠状巨孢囊霉的单主寄生营养液培养及宿主根分泌物特性*

为研究丛枝菌根真菌对宿主植物根分泌物的影响,在营养液培养条件下成功地建立了菌根真菌Gigaspora margarita与转移Ri T-DNA胡萝卜根器官之间的无菌单主寄生培养方法。接种发芽的孢子四个月后,对根段染色观测,发现萌发孢子的菌丝能够入侵到根段的皮层细胞内,根细胞内有菌丝的折叠卷曲现象,并开始形成了新的孢子。利用高压液相色谱测定各处理营养液中根分泌物的成分,发现菌根分泌的苹果酸和乙酸含量高于对照处理,菌根营养液的pH升高幅度也大于未接种的对照根。     

THE EFFECT OF SUGARS AND APPLIED CHEMICALS ON HETEROBLASTIC DEVELOPMENT IN IPOMOEA PURPUREA GROWN IN ASEPTIC CULTURE

Seedlings of Ipomoea purpurea were grown in aseptic culture in order to investigate more directly than had been possible in pot culture the effect of carbohydrate and protein nutrition on heteroblastic development which in this species involves a change from entire juvenile to lobed adult leaves. The effect of sugars was to accelerate the development of the adult leaf form while casein hydrolysate retarded it. The growth retardants, AMO-1618 and CCC, also promoted the formation of the adult leaf. These results are discussed in the light of current views on the factors controlling heteroblastic development.