MORPHOLOGICALLY DISTINCT STAGES IN THE GROWTH AND DEVELOPMENT OF RHIZOMES OF POA PRATENSIS L. AND THEIR CORRELATION WITH SPECIFIC GEOTROPIC RESPONSES

1965 ◽  
Vol 43 (10) ◽  
pp. 1163-1175 ◽  
Author(s):  
John E. Fisher
Keyword(s):  
Cross Section ◽  
Growth And Development ◽  
Apical Meristem ◽  
Poa Pratensis ◽  
Soil Surface ◽  
Leaf Primordium ◽  
Primary Stage ◽  
Secondary Stage ◽  
Small Pore ◽  
Tertiary Stage

Three distinct stages in the growth and development of the rhizomes of Poa pratensis L. can be distinguished. The names, primary, secondary, and tertiary are proposed to identify the stages. Primary stage rhizomes produce cataphylls elliptical in cross section, and poreless, or with a very small pore. Cataphyll primordia, initiated by the apical meristem, develop disproportionately, producing a hood-like cowling enclosing the apical meristem. The opening partially or completely closes by ontogenetic fusion. The geotropic response is plagiotropic Secondary stage rhizomes produce cataphylls with a marked longitudinal invagination. They are seldom poreless, and then only early in this stage. The apices are similar to primary stage apices. The geotropic response is diageotropic. Tertiary stage rhizomes progressively exhibit characteristics of true aerial shoots. Cataphylls develop a rudimentary leaf blade, ligule, and buliform-cell leaf-closure apparatus. However, a collar between blade and sheath does not form until the rhizome reaches the soil surface. The apex progressively develops the broad shield-shaped leaf primordium characteristic of aerial shoots. The geotropic response becomes strongly negatively orthogeotropic. Both the secondary and the tertiary stages are initiated by a change in the morphology of the apex and the cataphyll that precedes changes in the geotropic response of the rhizomes.

scholarly journals Iot Based Health Care System for Predicting Cardiac Issues

2020 ◽  
Vol 9 (4) ◽  
pp. 1174-1180
Keyword(s):  
Cost Effective ◽  
World Health ◽  
Primary Stage ◽  
Technological Advances ◽  
Long Duration ◽  
Secondary Stage ◽  
Tertiary Stage ◽  
Suitable Form ◽  
Health Organization

According to the survey conducted by the WHO (World Health Organization), out of 56.9 million deaths, Ischemic heart disease and Heart stroke account for 15.2 million deaths of the total deaths in 2016. These are regarded, as the Non-Communicable Diseases (NCD) also known as chronic diseases, tend to affect a person for a long duration. Along with in most of the cases, it is hard to find the disease existence in its primary stage; we can find it only with the symptoms like stroke or heart attack. Due to the lack of these symptoms, healthcare awareness and the financial needs many people are losing their lives. It is a very long process and cost effective. Hence, we are proposing a model, which predicts these symptoms with the implementation of latest technological advances like IoT, machine learning and deep learning algorithms. The proposed methodology takes place in three stages. Primary stage consists of collecting the data through sensors attached to the patient. Secondary stage involves the transfer of data from the microcontroller to the application and converting the data to suitable form. Tertiary stage involves feature extraction of the data and classification of the data using the CNN algorithm. All the stages run dynamically and generate the results based on the data collected. These results are then analyzed to check if the patient has arrhythmias or normal.

SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat

1995 ◽  
Vol 53 ◽  
pp. 978-979
Author(s):  
G. M. Hutchins ◽  
J. S. Gardner
Keyword(s):  
Growth And Development ◽  
Furfuryl Alcohol ◽  
Apical Meristem ◽  
Plant Cells ◽  
Triticum Aestivum L ◽  
Morphological Development ◽  
Naturally Occurring ◽  
Chinese Spring Wheat ◽  
Sem Study ◽  
Moist Environment

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.

scholarly journals Extended expression of MaKN1 contributes to the leaf morphology in aquatic forms of Myriophyllum aquaticum

Botany ◽  
2015 ◽  
Vol 93 (9) ◽  
pp. 611-621
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Leaf Morphology ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Myriophyllum Aquaticum ◽  
Knox Gene ◽  
Leaf Morphogenesis

Myriophyllum aquaticum (Vell.) Verdc. is heterophyllous in nature with highly dissected simple leaves consisting of several lobes. KNOX (KNOTTED1-LIKE HOMEOBOX) genes are believed to have played an important role in the evolution of leaf diversity. Up-regulation of KNOX during leaf primordium initiation can lead to leaf dissection in plants with simple leaves and, if overexpressed, can produce ectopic meristems on leaves. A previous study on KNOX gene expression in the aerial form of this species showed that this gene is expressed in the shoot apical meristem (SAM), as well as in leaf primordia P0 to P8. Based on these results, it was hypothesized that the prolonged expression of the MaKN1 (Myriophyllum aquaticum Knotted1-like homeobox) gene beyond P8, might play an important role in the generation of more lobes, longer lobes, and hydathode formation in the aquatic leaves of M. aquaticum. The technique of in situ hybridization was carried out using a previously sequenced 300 bp fragment of MaKN1 to determine the expression patterns of this gene in the shoot of aquatic forms of the plant. Expression patterns of MaKN1 revealed that the SAM and leaf primordia of aquatic forms of M. aquaticum at levels P0 (youngest) to P4 were distributed throughout these structures. The level of expression of this MaKN1 gene progressively became more localized to lobes in older leaf primordia (levels P5 to P12). Previous studies of aerial forms of this plant showed MaKN1 expression until P8. Our results with aquatic forms show that the highly dissected leaf morphology in aquatic forms was the result of the prolonged expression of MaKN1 beyond P8. This resulted in the formation of elongated and slightly more numerous lobes, and hydathodes in aquatic forms. These findings support the view that KNOX genes are important developmental regulators of leaf morphogenesis and have played an important role in the evolution of leaf forms in the plant kingdom.

Phyllotaxis of the palm Euterpe oleracea Mart. at the level of the shoot apical meristem

Botany ◽  
2010 ◽  
Vol 88 (5) ◽  
pp. 528-536 ◽  
Author(s):  
Denis Barabé ◽  
Laura Bourque ◽  
Xiaofeng Yin ◽  
Christian Lacroix
Keyword(s):  
Shoot Apical Meristem ◽  
Fundamental Theorem ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Divergence Angle ◽  
Euterpe Oleracea ◽  
The Mean ◽  
The Relationship ◽  
Euterpe Oleracea Mart

Previous studies on palm phyllotaxis deal mainly with the mature trunk. The goals of this study are (i) to determine the relationship between the number of parastichies, the divergence angle, and the plastochrone ratio at the level of the shoot apical meristem; (ii) to examine whether there are fluctuations in the divergence angle; (iii) to interpret the significance of phyllotactic parameters with respect to the mode of growth of the apex. The tubular base of the leaf primordium is more or less asymmetrical, and completely surrounds the shoot apical meristem. The phyllotactic system corresponds to a (2, 3) conspicuous parastichy pair. The mean divergence angle per apex varies between 126.9° ± 9.3° (mean ± SD) and 135. 8° ± 8.0°. Divergence angles for all apices fluctuate within a range of 115.89° to 157.33°. The mean plastochrone ratios between apices varies from 1.35 ± 0.18 to 1.58 ± 0.12. The plastochrone ratio at each plastochrone for all apices ranges from 1.09 to 2.00. There is no correlation between the angle of divergence and the plastochrone ratio. There is a fluctuation in the value of the divergence angle that falls within the range predicted by the fundamental theorem of phyllotaxis. The high value of the ratio of the diameter of leaf primordia over the diameter of the apex, and the long plastochrone might explain the lack of correlation between certain phyllotactic parameters.

Investigation on a two-stage platform of large stroke for broadband vertical vibration isolation

2018 ◽  
Vol 25 (6) ◽  
pp. 1233-1245 ◽  
Author(s):  
Xiling Xie ◽  
Mingke Ren ◽  
Hongbo Zheng ◽  
Zhiyi Zhang
Keyword(s):  
Vibration Isolation ◽  
Vertical Vibration ◽  
Optical Switches ◽  
Static Properties ◽  
Two Stage ◽  
Maximum Displacement ◽  
Primary Stage ◽  
Low Frequencies ◽  
Attenuation Rate ◽  
Secondary Stage

For the purpose of preventing vibration-sensitive optical switches from malfunction caused by broadband vertical vibration, a novel two-stage vibration isolation platform is proposed. The primary stage is a bellows-type isolator of large stroke and low isolation frequency, and the secondary stage is a small-stroke hybrid isolator composed of bellows and voice-coil actuators. In the primary stage, two pre-compressed horizontal bellows and one vertical bellows are used to counter the weight of the switch and to reduce the total height of the isolator. The static properties of the primary stage are analyzed, and the vibration isolation of the platform is investigated. Numerical results indicate that the two-stage platform is effective in isolating vertical vibration. Experiments are also conducted to verify the performance of the platform. It is exhibited that the transmissibility is less than 0 dB over 2 Hz, and the attenuation rate reaches −35 dB/dec at high frequencies. The frequency range of test is 2–200 Hz, and the maximum displacement is 10 mm at 2 Hz. In the secondary stage, the actuators can substantially suppress the resonance peak, and promote isolation performance at low frequencies.

High Temperature Creep Behavior of Austenitic Fe-Ni-Cr Alloy

2013 ◽  
Vol 686 ◽  
pp. 170-179 ◽  
Author(s):  
Esah Hamzah ◽  
Maureen Mudang ◽  
Ang Khwang Jenq ◽  
Muhammad Adil Khattak
Keyword(s):  
High Temperature ◽  
Detrimental Effect ◽  
Creep Damage ◽  
Transgranular Fracture ◽  
Creep Fracture ◽  
Secondary Stage ◽  
Tertiary Stage ◽  
The Difference ◽  
Temperature Test ◽  
Section Form

Creep damage investigation was carried out in Fe-Ni-Cr alloy at 800°C, 900°C, and 983°C using rectangular section form of specimen. In all the tests conducted on this material, some creep curves showed primary stage, secondary stage and tertiary stage. The creep fracture shows ductile transgranular fracture where separation occurred at the dendrites carbide interface suggesting that the detrimental effect of creep was compounded by precipitation of carbides at matrix. The presence of cavities may be due to the difference in thermal expansion characteristics of the austenite and carbide during high temperature test. Coarsening of carbides lead to cavities formation within the dendrite and carbide interface and form cavities linkage due to formation of crack and finally cause creep fracture. Increase in creep temperature it will lead to increase in creep rate. The fracture modes of creep samples were investigated to predict the failure mode.

GROWTH AND DEVELOPMENT OF THE LOWBUSH BLUEBERRY: APICAL ABORTION

1963 ◽  
Vol 41 (9) ◽  
pp. 1319-1324 ◽  
Author(s):  
W. G. Barker ◽  
W. B. Collins
Keyword(s):  
Vegetative Growth ◽  
Growth And Development ◽  
Apical Meristem ◽  
Shoot Growth ◽  
Strong Indication ◽  
Vegetative Tissue ◽  
Aerial Shoot ◽  
Lowbush Blueberry ◽  
Below Ground ◽  
High Level

The semicultivated lowbush blueberry is fire-pruned on a 3- to 4-year cycle. In spring, vegetative growth is accomplished through the development of an axillary bud on an aerial shoot. In a fire-pruned area, the growth is delayed in both its initiation and termination by as much as a month and arises either from axillary buds on the unburned below-ground portions of the aerial stems, or from rhizome seated buds. Shoot growth is terminated by the abortion of the apical meristem and the death of the proximal portions of the axis. Evidence is presented suggesting that the death of the apex is not triggered by an appropriate photoperiod. Further, although it is inherently controlled, it does not follow the production of a specified quantity (relative to clone) of leaf nor vegetative tissue and is not related to the development of a specified (per clone) leaf photosynthetic area. Finally, there is a strong indication that the death of the shoot is speeded by the presence of a high level of auxin.

Effect of Kochia (Kochia scoparia) Interference on Sunflower (Helianthus annuus) Yield

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Derek W. Lewis ◽  
Robert H. Gulden
Keyword(s):  
Great Plains ◽  
Growth And Development ◽  
Seed Quality ◽  
Seedling Recruitment ◽  
Soil Surface ◽  
Northern Great Plains ◽  
Limited Information ◽  
Leaf Stage ◽  
Action Threshold ◽  
Sunflower Crop

Kochia is a weed found in many sunflower fields across the Northern Great Plains. There is limited information about the ability of sunflower plants to compete with kochia, specifically when the weed grows both in the crop row and in the inter-row space, as in zero tillage systems that rely solely on herbicides to manage weeds. An experiment was conducted over seven site–yr, from 2009 to 2011, to determine the effect of kochia density and relative time of kochia seedling recruitment on sunflower growth and development, yield and seed quality. Kochia seed was broadcast on the soil surface at six densities, into sunflowers planted in 75-cm rows, either at the same time as the sunflower crop was planted (early weed seedling recruitment), or when the sunflowers were at the four-leaf stage (late weed seedling recruitment). When kochia plants emerged at the same time as the sunflowers, yield was reduced by up to 76% and sunflower head diam was reduced in four site–yr, stem diam was reduced in three site–yr, height was reduced in two site–yr and the number of leaves per sunflower plant was reduced in two site–yr The 5% action threshold for early emerging kochia was four kochia plants m−2in the combined site–yr analysis. Additionally, early recruiting kochia seedlings reduced sunflower seed size and seed weight at two and three site–yr, respectively. Kochia plants that emerged after the four-leaf stage of the sunflower crop did not affect sunflower growth and development, yield, or seed quality. To reduce the potential for yield and seed quality losses, sunflower growers should be proactive with respect to managing kochia in sunflowers, particularly when the kochia plants emerge at about the same time as the sunflowers.

scholarly journals SHOOT ORGANIZATION Genes Regulate Shoot Apical Meristem Organization and the Pattern of Leaf Primordium Initiation in Rice

2000 ◽  
Vol 12 (11) ◽  
pp. 2161-2174 ◽  
Author(s):  
Jun-Ichi Itoh ◽  
Hidemi Kitano ◽  
Makoto Matsuoka ◽  
Yasuo Nagato
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Leaf Primordium
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