Spores Of Equisetum Research Articles

Microscale Humidity Sensor Based on Iron-Coated Elaters of Equisetum Spores.

Humidity sensors deeply influence human manufacturing production and daily life, while researchers generally focus on developing humidity sensors with higher stability, higher linearity, rapid response time, etc. Yet, few people discuss measuring humidity in the microenvironment by miniaturizing sensor size into a microscale, in which the existing humidity sensors are difficult to reach. Accordingly, this study proposes a methodology for measuring relative humidity in the microscale by utilizing the distinctive morphologies of Equisetum spores across a range of relative humidities between 50% and 90%. Equisetum spores are responsive to changes in ambient relative humidity and remain in their original activities even after iron sputtering, which aims to endow the sensor with magnetic properties. The test performed in this study demonstrated a response time of 3.3 s and a recovery time of 3.6 s. In the first application, we employed such microscale sensors to work in the channel of the microfluidic chip or the cell migration microchip, as an example of working in the microenvironment. COMSOL Multiphysics 6.2 software was also used to simulate the change in relative humidity in such microchannels. Secondly, such microscale sensors are combined with smartphone-based microscopy to measure the humidity of the skin. These microscale sensors pave the new way to sensing humidity in microenvironments.

Relative importance of hydrological and climatic controls on Holocene paleoenvironments inferred using diatom and pollen records from a lake in the central Hudson Bay Lowlands, Canada

Postglacial paleoenvironmental changes and landscape development in the Hudson Bay Lowlands in subarctic Canada were inferred using sediment properties and diatom and pollen assemblages in the sediments of a lake raised above the surrounding peatlands in an ice-marginal landform. Coarse-grained, inorganic sediments at the base of the Lake AT01 core suggest a high-energy periglacial environment, following isostatic emergence from Hudson Bay around 6840 cal. BP. Initial diatom assemblages dominated by Fragilaria spp., and pollen of Shepherdia canadensis, indicate early successional conditions in a recently deglaciated environment. Around 6200 cal. BP, tychoplanktonic Fragilarioid diatoms are replaced by large benthics. Coincident increases in Equisetum spores, Cyperaceae pollen and sediment organic matter suggest the establishment of a more productive macrophyte-rich shallow lake. While the Holocene Thermal Maximum and subsequent Neoglacial may have contributed to these shifts, pollen and diatom records suggest only subtle responses to Holocene climatic changes. A core chronology inferred from radioisotopes suggests a hiatus in sediment accumulation between 3650 and 200 cal. BP. Peaks in carbonate inferred from loss-on-ignition and increases in bulk density in that section of the core suggest some effect of erosional or thermokarst processes, or the breaching of a sandbar, now a remnant island in the lake, in the drainage of the lake and ensuing hiatus. Sediment accumulation resumed within the past two centuries; diatom assemblages in the uppermost section are characterized initially by benthic diatoms of smaller valve size compared with the pre-hiatus assemblages. More recently, increases in the planktonic diatom Cyclotella stelligera are recorded, signaling significant environmental changes.

The sedimentary sequence from the Lake Ķūži outcrop, central Latvia: implications for late glacial stratigraphy

Sediment samples from an outcrop in the near-shore area of Lake Ķūži (Vidzeme Heights, Central Latvia) were investigated using palaeobotanical (pollen and macrofossil analysis) and lithological (grain-size analysis) methods and accelerator mass spectrometry 14 C dating. A dark, organic-rich sediment layer was found below 1.7 m of sandy layers approximately 30 cm above the present lake level. Radiocarbon dating of a wood sample from the lowermost layer (11 050 ± 60 14 C BP, 13 107- 12 721 cal BP) shows that the layer is of late glacial age. The composition of the pollen spectra is characterized by Betula nana, Cyperaceae pollen and spores of Equisetum, confirming that the lowermost sediments were formed during the late glacial. Fossils of obligate aquatic organisms in the upper layer, which include oospores of Characeae and seeds of Potamogeton, indicate an open water environment. Pollen of Myriophyllum and Potamogeton and non-pollen palynomorphs, such as algal Botryococcus and Pediastrum cf. boryanum, confirm this conclusion. The pollen assemblage from the greyish loam layer following this lacustrine phase shows a pattern characteristic of the Younger Dryas vegetation before the start of the real expansion of birch forests at the beginning of the Holocene.

Desiccation‐time limits of photosynthetic recovery in Equisetum hyemale (Equisetaceae) spores

The chlorophyllous spores of Equisetum survive desiccation, yet cannot tolerate this quiescent state for more than ~2 wk. The hypothesis that spore viability of Equisetum hyemale L. is limited by inhibition of photosynthetic recovery was tested using chlorophyll a fluorescence and oxygen-exchange analyses. Experimental spores were desiccated at 2% relative humidity and 25C for time periods of 24 h, 1 wk, and 2 wk, and then rehydrated at 200 mmol photons/m2s (PAR) and 25C for up to 24 h. Spores desiccated for 24 h recovered photosynthetic competence very rapidly during rehydration, reaching the O2 compensation point in 6.3 ~ 0.3 (mean +/- SE) min. Recovery of photosynthetic performance of spores desiccated for 1 wk was slower, as judged by significantly slower increases of (1) photochemical efficiency of photosystem (PS) II, (2) PS II quinoneB-reducing center concentration, (3) quinoneB concentration, (4) water-oxidation activity, (5) rate of light-induced O2 evolution, and (6) apparent quantum yield of net O2 exchange. Photosystem-II and whole-spore photosynthetic competence of 2-wk desiccated spores was increasingly impaired, and did not recover during rehydration. Origin fluorescence yield and dark respiration were not affected by desiccation time following rehydration. The results suggest that the extremely short viability of disseminated spores of Equisetum hyemale is due to the inability to recover losses of water oxidation and photosystem II-core function following 2 wk of desiccation.

Extending the Viability of Equisetum hyemale Spores

The green spores of Equisetum normally are viable for only short periods of time. Thus, these spores are available to produce gametophytes for brief periods during the year in many parts of the world. Over the years efforts have been made to keep the spores viable for extended periods of time. In this study, ripe cones of E. hyemale were stored frozen at -70?C. This procedure extended the viability of the spores for more than a year, and 37% of the spores stored frozen for a year germinated and formed gametophytes. Green spores of pteridophytes usually have short viabilities and some of the shortest are reported for Equisetum (Lloyd and Klekowski, 1970). The best possibility to obtain substantial spore germination is to use spores from re- cently opened cones (Hauke, 1969). Fresh spores are easier to collect from tropical species of Equisetum because ripe cones are available essentially all year (Hauke, 1969). This is not the case for species from the temperate zone, because their cones are ripe for only short times during the growing season. Outside the tropics, fresh Equisetum spores are unavailable for most of the year. Efforts have been made to extend the viability of Equisetum spores so that living spores are available for a greater portion of the year. Castle (1953) stored sporangia and spores of E. arvense in a sterile nutrient solution at 5?C. Spores stored in this manner remained viable for three months. Hauke (1969) tried freezing dry and wet spores or storing wet spores at 80C. The best of these procedures, wet spores at 8?C, kept the spores of E. myriochaetum alive for 1.5 months. Duckett (1970a) stored ripe cones of E. arvense in sterile nutrient solutions at 4?C. Germination was obtained after two months of storage but none occurred after five months. Jones and Hook (1970) placed freshly shed spores of E. telmateia in bottles, added 2-3 cm of glycerine, capped the bottles, and stored them at -10?C. The percentages of germination were 54, 74, and 37 for spores stored under these conditions for 1, 2, and 3 years respectively. The technique of Jones and Hook (1970) was superior to the others for main- taining the viability of Equisetum spores. However, recovering the spores from the glycerine is somewhat involved. The spores have to be washed out of the glycerine with nutrient solution or water before they can be placed in culture. The present study was carried out in an effort to devise a simpler procedure for storing and sowing Equisetum spores.

Growth and Development in Microculture of Gametophytes from Stored Spores of Equisetum

Spores of Equisetum telmateia Ehrh. retained 74% viability after two years of storage under glycerine at minus 10 C. Stored spores germinated, grew, and formed mature gametangia on mineral nutrient media in petri plates and in micro-cultures where detailed cytological observations could be made. Growing gametophytes were favorable materials for studies of mitosis, chloroplast replication, gametogenesis, and senescence.

Spores á expansion en forme d'élatéres du crétacé moyen d'afrique occidentale

Albian and Cenomanian sediments from basins in West Africa are characterized by organisms of uncertain botanical affinities which have in common projections like “élatères” of Equisetum spores. They include the genera GaleacorneaStover emend., Elaterosporites nov. gen. (GaleacorneaStover pro parte), ElaterocolpitesJardiné et Magloire, Sofrepites nov. gen. and an incertae sedis. The stratigraphic range of species in the basins of Senegal (plus Gambia and Portuguese Guinea), Ivory Coast,Nigeria, Gabon, Algeria and Maranhão (Brazil) is given in a comparative chart. These sporomorphs, which extend from Middle Albian to Upper Cenomanian (Turonian?), have a high stratigraphical value.

Growth of Pteridium aquilinum (L.) Kuhn Gametophytes in Submerged Culture

The culture of fern gametophytes under aseptic conditions is commonly carried out on various mineral solutions with or without agar. In these methods the ferns develop on the surface of the culture medium. In order to obtain a higher yield of gametophyte tissue, an attempt was made to develop a method for growing these plants in submerged, agitated, liquid cultures, thereby utilizing the entire volume of the medium instead of the surface alone. Since submerged gametophytes develop very slowly, the plants were aerated by bubbling sterile air through the medium. This paper will describe the method developed and will compare the development of gametophtyes grown by this method to that of ferns grown by more standard culture procedures. Two papers were found in the literature that described the development of lower archegoniates in agitated cultures: Nakazawa (1956) reported on the germination of Equisetum spores in aerated submerged cultures, and Machlis and Doyle (1962) described a technique for the growth of liverworts, mosses, and Equisetumn in flasks agitated on a rotary shaker. Voeller (1964) has described the growth of fern gametophytes in submerged cultures that were not agitated; the development was stimulated by the addition of coconut milk to the medium. Spores of the Bracken Fern, Pteridium aquilinum (L.) Kuhn, were collected in September, 1963, in Pulaski County, Indiana, and stored under refrigeration. The spores were filtered through six layers of lens paper to remove sporangia. For agitated cultures or cultures using a medium solidified with agar,

Zur Frage eines Photoinaktivierungs-Effektes bei der Polaritätsinduktion inEquisetumsporen undFucus zygoten

Polarity was induced in spores ofEquisetum variegatum and zygotes ofFucus serratus by monochromatic light; the cells were lit partially or by combinations of different types of irradiation.

Conditions for the Germination of the Spores of Bryophytes and Pteridophytes

The more important results of the foregoing investigations may be stated as follows:-- 1. Under ordinary conditions of temperature and inorganic nourishment, moss and liverwort spores are unable to germinate in the dark. Spores when subjected to the more strongly refrangible rays of the spectrum only behave the same as in darkness. 2. Organic nourishment in the form of either peptone or grape sugar will call forth the germination of moss spores in complete darkness. Moss protonemata are able to attain a considerable size in the dark, by a saprophytic nourishment, although the vigor of growth is considerably below the normal. 3. Under ordinary conditions of temperature and inorganic nourishment, fern spores are unable to germinate in the dark.A higher temperature, however, will furnish conditions for the germination in complete darkness. 4. The spores of Equisetum germinate apparently as well in darkness as in light and at the ordinary room temperature of 19-21⚬C. The experiments for this work were conducted during 1896-7 at the Botanical Institute, Leipzig, under the direction of Herr Geheimrat Professor Dr. Pfeifer, to whom thanks are due for many valuable suggestions.