In vitro propagation of Alstroemeria ‘Alsaan’

Plantlets were regenerated from Alstroemeria Alsaan rhizome tips cultured in vitro on solid and liquid media based on Murashige and Skoog salt formulation. The quality of the cultures was superior when intact rather than longitudinally sliced rhizome tips were used as explants and when a temperature of 8°C rather than 22°C was used at the initiation stage. More roots were produced on rhizome tips containing a rhizome apical meristem than on rhizome sections lacking such a meristem. Most (90%) of the rooted plantlets were successfully acclimatized and developed into true-to-type flowering plants.     

Rhizome induction and plantlet regeneration of Cymbidium goeringii from flower bud cultures in vitro

Apical flower buds of Cymbidium goeringli Reichenbach fil. (ca 2 mm long) exeised from infloreseences (ca 5 cm long) were explanted on modified Murashige & Skoog medium (=MS medium) supplemented with N⁶-benzyladenine (BA) and -naphthaleneacetic acid (NAA). Within 107 days of culture, swelling growth, chlorophyll synthesis, and subsequent rhizome differentiation were observed. MS medium containing 0.1 mg l^-1 BA and 10 mg l^-1 NAA was found to be optimal for initiating rhizome development and subsequent plantlet regeneration.Explants cultured on MS medium supplemented with 1 mg l^-1 NAA alone formed a mass of rhizome branches. Multiple shoots of rhizome branches were induced from apical segments when rhizomes were transferred to MS medium containing 0.1 mg l^-1 BA and 10 mg l^-1 NAA.Abbreviations NAA -naphthaleneacetic acid - BA N⁶-benzyladenine     

Rhizome dynamics and resource storage in Phragmites australis

Seasonal changes in rhizome concentrations of total nonstructural carbohydrates (TNC), water soluble carbohydrates (WSC), and mineral nutrients (N, P and K) were monitored in two Phragmites australis stands in southern Sweden. Rhizome biomass, rhizome length per unit ground area, and specific weight (weight/ length ratio) of the rhizomes were monitored in one of the stands.Rhizome biomass decreased during spring, increased during summer and decreased during winter. However, changes in spring and summer were small (< 500 g DW m-2) compared to the mean rhizome biomass (approximately 3000 g DW m^–2). Winter losses were larger, approximately 1000 g DW m-2, and to a substantial extent involved structural biomass, indicating rhizome mortality. Seasonal changes in rhizome length per unit ground area revealed a rhizome mortality of about 30% during the winter period, and also indicated that an intensive period of formation of new rhizomes occurred in June.Rhizome concentrations of TNC and WSC decreased during the spring, when carbohydrates were translocated to support shoot growth. However, rhizome standing stock of TNC remained large (> 1000 g m^–2). Concentrations and standing stocks of mineral nutrients decreased during spring/ early summer and increased during summer/ fall. Only N, however, showed a pattern consistent with a spring depletion caused by translocation to shoots. This pattern indicates sufficient root uptake of P and K to support spring growth, and supports other evidence that N is generally the limiting mineral nutrient for Phragmites.The biomass data, as well as increased rhizome specific weight and TNC concentrations, clearly suggests that reloading of rhizomes with energy reserves starts in June, not towards the end of the growing season as has been suggested previously. This resource allocation strategy of Phragmites has consequences for vegetation management.Our data indicate that carbohydrate reserves are much larger than needed to support spring growth. We propose that large stores are needed to ensure establishment of spring shoots when deep water or stochastic environmental events, such as high rhizome mortality in winter or loss of spring shoots due to late season frost, increase the demand for reserves.     

The morphology,taxonomy and evolution ofRhodocoma (Restionaceae)

The vegetative and reproductive morphology, culm and rhizome anatomy and seed surface micromorphology ofRhodocoma are described. It is shown that this variation is best contained by recognizing three new species in the genus. These new taxa are described, and the phylogeny of the genus is investigated by cladistic analysis. The environmental parameters and distributions of the species are related to the cladogram. This suggests that the species are at present ecologically separated, and indicates that the speciation may have been sympatric. This is the first support for the hypothesis that sympatric speciation may have been important in the speciose Cape flora.     

Plant contents and quality of makhana (Euryale ferox)

Summary As a part of integrated study of makhana, the mineral contents of the plant parts and the fruits of makhana (Euryale ferox) have been presented here. It has been observed that the fruits were not only rich in minerals but also in protein. The plant parts also contained high amounts of micronutrients. Its fruits are, therefore, a good supplement for minerals which are produced from otherwise agriculturally waste (water-logged) areas.     

Factors affecting the initiation of mini-rhizomes from Trillium erectum and T. grandiflorum tissues in vitro

Leaf and stem explants of Trillium grandiflorum and T. erectum produced mini-rhizomes (MRs) in vitro which gave rise to shoots and roots. The apical portion of the stem and the basal portion of the leaves were the most effective explants from these tissues, while stem tissue was more responsive than leaf tissue. The best response with both species was observed on half-strength MS basal medium supplemented with cytokinin and auxin. T. erectum was more responsive than T. grandiflorum overall, and in some cases produced MRs in the absence of growth regulators. Culture at 21°C appeared to stimulate growth from T. grandiflorum tissues, compared with controls at 27°C, whereas the outgrowth of shoots from MRs was inhibited in both species at 21°C. In vitro production of MRs could provide a more rapid, alternative propagation method for these species than traditional methods.     

Phenological growth stages of North American ginseng (Panax quinquefolius)

The BBCH (Biologische Bundesanstalt, Bundessortenamt, Chemische Industrie) scale is used to describe the phonological growth stages of North American ginseng (Panax quinquefolius). Eight principal growth stages for germination and bud development, leaf development (crop canopy), root and perennating bud formation, peduncle elongation and inflorescence development, flowering and fruit set, development of fruit, ripening of fruit and senescence, and 42 secondary growth stages are described. A practical use of the scale is proposed with reference to the timing of application of agrochemicals for disease control.     

异色芋生物学特性观察

本文对观赏植物异色芋（ＣｏｌｏｃａｓｉａｈｅｔｅｒｏｃｈｒｏｍａＨ．ＬｉｅｔＺ．Ｘ．Ｗｅｉ）在昆明栽培环境下的生物学特性进行总结,为商品化栽培异色芋提供了理论依据,为其分类也提供了一定的有益补充。结果表明：一年生植株不开花,根茎也不产生分枝;二年生植株开花率为７３．６％,根茎平均分枝３．６条。异色芋３月上旬开始萌动,７月中旬抽花梗,８月上旬开花,１１月份地上部分枯萎,因此在昆明异色芋生育期约２６０ｄ。     

甘草根和根状茎的发育解剖学研究

甘草（ＧｌｙｃｙｒｒｈｉｚａｕｒａｌｅｎｓｉｓＦｉｓｃｈ）实生苗具直根系。其根端原分生组织具三层原始细胞,外层产生表皮和根冠,中层和内层分别产生皮层和中柱。根的初生木质部四原型,由中柱鞘细胞产生第一次周皮。成长根中央的初生木质部由于导管周围薄壁细胞的增殖而被分割成几部分,使导管分子星散分布于薄壁细胞间。实生苗生长到第三年春由于叶节处的更新芽萌发形成最初的根状茎,根状茎顶端的原分生组织由两层原套细胞和一团原体细胞组成。初生结构的分化开始于皮层和髓两部分基本分生组织,而原形成层早期在根状茎横切面上呈连续的分生组织环。以后在环内逐渐分化出原形成层束,由它分化出初生锥管束,根状茎第一次周皮产生于初生韧皮部外方的第五或第六层皮层细胞。     

辽宁中侏罗世紫萁根茎化石一新种

本文报道的Millerocaulis liaoningensis sp. nov., 在我国是继M. hebeiensis(Wang)Tid.well之后的又一个有关中侏罗世紫萁科根茎化石。其主要特征是:外韧网管中柱,木质部圆筒12—17个管胞厚,由13—15个木质部束组成,叶迹从木质部圆筒分离时通常仅有一个原生木质部丛,柄基硬化环异质,在远轴边有一个约占环壁1/2的厚壁纤维带,柄基木质部束凹面有一个新月形的厚壁组织块,柄基托叶翼中每侧仅有一个不规则的厚壁组织块,不定根非常发育,在柄基的硬化环内根迹多达10个以上。