蓝花野茼蒿，中国菊科一新记录归化种

蓝花野茼蒿Crassocephdum rubens(Juss.ex Jacq.)S.Moore是一种原产非洲的常见菊科杂草,近年在我国云南发现有逸生,为我国新记录的归化种.     

菜蕨的组织培养与植株再生

1植物名称菜蕨[Callipteris esculenta（Retz．）J．Sm．ex Mooreet Houlst．],又名水蕨菜、猫菜、过沟菜蕨、青蕨、蕨猫、蕨儿菜、山风尾等。     

Gas space and oxygen exchange in roots of Avicennia marina (Forssk.) Vierh. var. australasica (Walp.) Moldenke ex N. C. Duke,the Grey Mangrove

Aerenchyma pervades the cortex of the whole root system in Avicenniamarina var. australasica plants grown for 3 to 5 years in artificial-tidaltanks. The gas spaces appear to be schizogenous in all but the finest roots,where some apparently lysigenous gas spaces develop. Gas spaces in thepith are small. Pneumatophores examined at the time the tips are growingpossess subrisules on the tips as well as lenticels on mature regions. At othertimes subrisules are not seen. When the tide floods the pneumatophores,gas pressure and oxygen concentration go down – pressure by 1.7 kPa orless, but oxygen by as much as 3 mol m^-3, or more in some cases.On draining, pressure recovers immediately to atmospheric, but oxygenslowly rises to a plateau below the concentration in the atmosphere. Thechanges in oxygen concentration are consistent with oxygen supply bydiffusion. The contribution of oxygen made by the small influx of air onpressure recovery is only a minor fraction of the respiratory oxygenrequirement. Wet weather at low tide restricts gas exchange, affecting bothpressure and oxygen. The pressure and oxygen changes are repeated overmany tidal cycles. The results are compared with those for other speciesand situations in the literature.     

Guaianolide sesquiterpenes from Pulicaria crispa (Forssk.) Oliv

A phytochemical study of the asteraceous herb Pulicaria crispa (Forssk.) Oliv. resulted in the characterisation of three guaianolide sesquiterpenes, 2alpha,4alpha-dihydroxy-7alphaH,8alphaH,10alphaH-guaia-1(5),11(13)-dien-8beta,12-olide (1), 1alpha,2alpha-epoxy-4beta-hydroxy-5alphaH,7alphaH,8alphaH,10alphaH-guaia-11(13)-en-8beta,12-olide (2) and 5,10-epi-2,3-dihydroaromatin (3). The structures were assigned on the basis of extensive 1 and 2D NMR experiments. Compound 3 exhibited weak antimycobacterial activity against Mycobacterium phlei with a minimum inhibitory concentration of 0.52 mM and cytotoxicity (IC50 of 5.8+/-0.2 microM) in a human bladder carcinoma cell line, EJ-138.     

肿足蕨的配子体发育研究

对肿足蕨(Hypodematium crenatum(Forssk.)Kuhn)的孢子进行人工培养,在显微镜下观察其孢子萌发和配子体发育.结果表明,肿足蕨的孢子深褐色,二面体型,单裂缝,具周壁,有密集的褶皱状纹饰.孢子赤道面观为肾形,极面观为椭圆形.孢子萌发类型为书带蕨型(Vittaria-type),原叶体发育为叉蕨(Aspidium-type).成熟原叶体为对称心形,原叶体上毛状体极其发达,有两种不同类型的毛状体,分别为乳头状和长针状.假根分叉,常见膨大.成熟的原叶体为雌雄同株,精子器由3个细胞构成,同一原叶体上同时存在处于不同发育时期的精子器,颈卵器长且较为弯曲.肿足蕨的配子体发育表现出较为进化的特点,同时也形成了对石灰岩生境的高度适应机制.     

Stem anatomy and development of inter- and intraxylary phloem in Leptadenia pyrotechnica (Forssk.) Decne. (Asclepiadaceae)

Modification of external morphology and internal structure of plants is a key feature of their successful survival in extreme habitats. They adapt to arid habitats not only by modifying their leaves, but also show several modifications in their conducting system. Therefore, the present study is aimed to investigate the pattern of secondary growth in Leptadenia pyrotechnica (Forssk.) Decne., (Asclepiadaceae), one such species growing in Kachchh district, an arid region of Gujarat State. A single ring of vascular cambium, responsible for radial growth, divided bidirectionally and formed the secondary xylem centripetally and the phloem centrifugally. After a short period of secondary xylem differentiation, small arcs of cambium began to form secondary phloem centripetally instead of secondary xylem. After a short duration of such secondary phloem formation, these segments of cambium resumed their normal function to produce secondary xylem internally. Thus, the phloem strands became embedded within the secondary xylem and formed interxylary phloem islands. Such a recurrent behavior of the vascular cambium resulted in the formation of several patches of interxylary phloem islands. In thick stems the earlier formed non-conducting interxylary phloem showed heavy accumulation of callose on the sieve plates followed by their crushing in response to the addition of new sieve elements. Development of intraxylary phloem is also observed from the cells situated on the pith margin. As secondary growth progresses further, small arcs of internal cambium get initiated between the protoxylem and intraxylary phloem. In the secondary xylem, some of the vessels are exceptionally thick-walled, which may be associated with dry habitats in order to protect the vessel from collapsing during the dryer part of the year. The inter- and intraxylary phloem may also be an adaptive feature to prevent the sieve elements to become non-conducting during summer when the temperature is much higher.     

Water relations determine short time leaf growth patterns in the mangrove Avicennia marina (Forssk.) Vierh.

High‐resolution leaf growth is rarely studied despite its importance as a metric for plant performance and resource use efficiency. This is in part due to methodological challenges. Here, we present a method for in situ leaf growth measurements in a natural environment. We measured instantaneous leaf growth on a mature Avicennia marina subsp. australasica tree over several weeks. We measured leaf expansion by taking time‐lapse images and analysing them using marker tracking software. A custom‐made instrument was designed to enable long‐term field studies. We detected a distinct diel growth pattern with leaf area shrinkage in the morning and leaf expansion in the afternoon and at night. On average, the observed daily shrinkage was 37% of the net growth. Most of the net growth occurred at night. Diel leaf area shrinkage and recovery continued after growth cessation. The amount of daily growth was negatively correlated with shrinkage, and instantaneous leaf growth and shrinkage were correlated with changes in leaf turgor. We conclude that, at least in this tree species, instantaneous leaf growth patterns are very strongly linked to, and most likely driven by, leaf water relations, suggesting decoupling of short‐term growth patterns from carbon assimilation.     

An unrecorded species in Korea:Monochasma sheareri (S. Moore) maxim, ex Franch. Et Sav. (Scrophulariaceae)

Plants of a genus and species previously unrecorded in Korea were collected from the hillside along a forest road at the Gwaneum peak in the Byeonsanbando National Park, Buan-gun, Jeollabuk-do, together with plants belonging to Gramineae and Cyperaceae.Monochasma sheareri (S. Moore) Maxim, ex Franch. et Sav. (Scrophulariaceae) is most similar toM. savatieri Franch. ex Maxim., but differs distinctively in several morphological characters. WhereasM. sheareri exhibits a slender stem, and a calyx that is longer than the corolla, plants ofM. savatieri, which is distributed in Japan and China, have stout stems with glandular pilose trichomes, along with calyxes that are shorter than their corollas. In addition, seeds ofM. sheareri are elliptical, with falcate trichomes on their surfaces. This new plant has been given a Korean name, “Byeon-san-but-sal-i-pul”, based on its parasitic habit and features of its natural habitat. Here, we describe its morphological characters and provide a taxonomic key and illustrations, plus photographs of the flower, fruit, and roots.     

Salinity tolerance of Avicennia marina (Forssk.) Vierh. from Gujarat coasts of India

Greenhouse experiments were conducted to assess the effects of soil salinity on emergence, growth, water status, proline content and mineral accumulation of seedlings of Avicennia marina (Forssk.) Vierh. NaCl was added to the soil and salinity was maintained at 0.2, 2.5, 5.1, 7.7, 10.3, 12.6, 15.4, 17.9, 20.5, 23.0, 25.6 and 28.2 psu. A negative relationship between seedling emergence and salt concentration was obtained. Nevertheless, this mangrove is highly salt tolerant during germination. Growth of seedlings was significantly promoted by low salinity and optimum growth was obtained at 15.4 psu. Higher salinities inhibited plant growth. Growth and dry matter accumulation in tissues followed the same optimum curve. Water potential of tissues became significantly more negative with increasing salinity, and proline content significantly increased. Moreover, water potential and proline content of tissues displayed an S-curve with the inflection point below ∼10 psu. The concentration of Na in tissues increased significantly, whereas K, Ca, Mg, N and P content decreased.