Studies on bud development in the rhizome of Agropyron repens. 1. The influence of temperature, light intensity, and bud position on the pattern of development

1970 ◽  
Vol 48 (11) ◽  
pp. 1903-1909 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Shoot Formation ◽  
Nitrogen Level ◽  
Influence Of Temperature ◽  
Bud Development ◽  
Lateral Buds ◽  
Bud Position ◽  
Low Nitrogen ◽  
Agropyron Repens

When plants of Agropyron repens L. Beauv. are grown at a low nitrogen level, decapitation of the rhizomes releases the lateral buds from inhibition and results in a well-marked polarity of bud development. This polarity is typically characterized by the restriction of shoot development to the bud nearest the apical end of the rhizome, the production of rhizomes from buds at a greater distance from the apex, and a tendency for the buds at the basal nodes to remain inhibited.It was shown that this pattern of bud development is readily affected by environmental conditions. Increasing the temperature from 15° to 25 °C caused a marked increase in shoot formation at the expense of rhizome production and a small increase in the number of dormant buds. Reducing the light intensity had a similar but much more pronounced effect. The position of the buds in relation to the cut end of the rhizome was relatively less important as a morphogenetic factor than their position on the intact plant.As a working hypothesis, based on previous results, it is suggested that a gradient in the C/N ratio might account for the observed polarity of bud development.

Studies on bud development in the rhizome of Agropyron repens. II. The effect of the nitrogen supply

1972 ◽  
Vol 50 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Dry Weight ◽  
Nitrogen Supply ◽  
Parent Plant ◽  
Bud Development ◽  
Apical Buds ◽  
Rooting Medium ◽  
Correlative Inhibition ◽  
Bud Growth ◽  
Low Nitrogen ◽  
Agropyron Repens

Bud growth on isolated rhizomes of Agropyron repens showed a basipetal gradient of decreasing activity and was strongly inhibited at the basal nodes. This evident polarity was correlated with a gradient of decreasing nitrogen content at successively older nodes and with an apparent translocation of nitrogen from the basal to the apical nodes. Isolating the buds from one another reduced growth of the apical buds and prolonged the growth of buds at the basal nodes so that the polarity of bud growth, although still apparent, was much reduced.Supplying nitrogen as NH4NO3 through the cut end of rhizomes still attached to the parent plant caused apical buds to develop as shoots instead of rhizomes. Increasing the nitrogen supply to the rooting medium extended this response to buds at older nodes, restricting rhizome production to basal buds whose growth was inhibited in low nitrogen rhizomes.Buds developing as shoots had a considerably higher total nitrogen and moisture content and a lower dry weight than buds developing as rhizomes.The results emphasized the importance of the nitrogen supply not only in determining the polarity of bud growth and the degree of correlative inhibition, but also as a morphogenetic factor controlling bud development.

ENVIRONMENTAL CONTROL OF BUD AND RHIZOME DEVELOPMENT IN THE SEEDLING OF AGROPYRON REPENS L. BEAUV.

1967 ◽  
Vol 45 (8) ◽  
pp. 1315-1326 ◽  
Author(s):  
G. I. McIntyre
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Environmental Control ◽  
Nitrogen Supply ◽  
High Nitrogen ◽  
Bud Development ◽  
High Nitrogen Level ◽  
Terminal Shoot ◽  
Rhizome Development ◽  
Agropyron Repens

The effects of various environmental conditions on bud development in seedlings of Agropyron repens L. Beauv. were investigated. The bud in the axil of leaf 1 was the most responsive. At a high nitrogen level (315 p.p.m.) most of the buds at this position developed as tillers, and at a low level (2.1 p.p.m.) as rhizomes. A transition from rhizome to shoot development was induced by increasing the nitrogen supply after the rhizomes were initiated. Temperature had a similar effect, tillers being produced at a high (day) temperature (27 °C) and rhizomes at a low temperature (10 °C). Reducing the daylength from 18 to 9 h strongly promoted tillering and almost completely prevented rhizome development. A reduction of light intensity from 4000 to 2000 ft-c did not affect bud development but appeared to increase the tendency for rhizomes to form a terminal shoot. Similar effects were shown by the buds at the coleoptile and leaf 2 positions but the inherent tendency for the former to develop as rhizomes and the latter as tillers limited their response.There was some evidence from these results that bud and rhizome development is controlled by a similar mechanism and that the carbohydrate level may be an important factor in determining the inherent pattern of bud development.

Apical dominance in the rhizome of Agropyron repens. Some factors affecting the degree of dominance in isolated rhizomes

1971 ◽  
Vol 49 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Soluble Nitrogen ◽  
Small Reduction ◽  
High Nitrogen ◽  
Factors Affecting ◽  
Lateral Buds ◽  
Degree Of Dominance ◽  
High Nitrogen Level ◽  
Low Nitrogen ◽  
Agropyron Repens

A study of apical dominance in isolated rhizomes of Agropyron repens L. Beauv. showed that increasing the length of the rhizome significantly reduced the degree of dominance only in rhizomes from plants grown at a high nitrogen level (210 ppm). Exposing the rhizomes to light also reduced dominance more effectively in high-nitrogen rhizomes but the response of rhizomes from low-nitrogen plants was greatly increased by supplying water through the end of the rhizome. Further experiments with low-nitrogen rhizomes showed that buds could be released from apical dominance by treatment with kinetin. When isolated from the plant the buds showed a significant increase in length after 24 h and an associated increase in moisture and insoluble nitrogen content. Soluble nitrogen and carbohydrate increased concurrently during the next 24 h. Rhizomes kept in darkness showed a small reduction of bud inhibition when water was supplied through the cut end; NH4NO3 solution had a greater effect, while solutions in which both nitrogen and carbohydrate (as sucrose) were supplied resulted in the almost complete elimination of apical dominance.The results suggest that apical dominance in isolated, low-nitrogen rhizomes was due mainly to competition between the apex and the lateral buds for water, nitrogen, and carbohydrate.

Developmental studies on Euphorbia esula. The influence of the nitrogen supply on the correlative inhibition of root bud activity

1972 ◽  
Vol 50 (5) ◽  
pp. 949-956 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Nitrogen Supply ◽  
Euphorbia Esula ◽  
Nitrogen Level ◽  
Developmental Studies ◽  
Subsequent Increase ◽  
Lateral Buds ◽  
Lateral Shoots ◽  
Correlative Inhibition ◽  
Low Nitrogen

When seedlings of leafy spurge (Euphorbia esula L.) were grown at a low nitrogen level (10.5 ppm) the growth of the lateral buds on the shoot was completely arrested by apical dominance while the buds on the roots, although also inhibited, showed considerably greater activity. At a higher nitrogen level (210 ppm) apical dominance was markedly reduced but the resulting outgrowth of the lateral buds increased the inhibiting capacity of the shoot, limiting root bud response. When the main shoot was decapitated the degree to which root bud growth was suppressed by a given number of lateral shoots was inversely related to the nitrogen supply. Inhibition of the root buds by the lateral shoots could be significantly reduced by growing the plants initially at a low nitrogen level so that growth of the lateral buds was arrested. A subsequent increase in the nitrogen supply strongly promoted the growth of the roots buds, some of which were sufficiently released from inhibition to emerge as leafy shoots.

scholarly journals Morphological and physiological plasticity response to low nitrogen stress in black cottonwood (Populus deltoides Marsh.)

2021 ◽  
Author(s):  
Cun Chen ◽  
Yanguang Chu ◽  
Qinjun Huang ◽  
Changjun Ding ◽  
Weixi Zhang ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Nitrogen Use Efficiency ◽  
Root Biomass ◽  
Populus Deltoides ◽  
Leaf Traits ◽  
Nitrogen Level ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Normal Nitrogen ◽  
Low Nitrogen

AbstractIt is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their productivity. In this study, both were evaluated for 338 Populus deltoides genotypes from six provenances. The plants were cultured under normal nitrogen (750 μM NH4NO3) and low nitrogen (5 μM NH4NO3) conditions for 3 months. Growth, chlorophyll content and glutamine synthetase activity of each genotype were measured. Under low nitrogen, heights, ground diameter, leaf area, leaf and root biomass, and chlorophyll contents were significantly lower than those under normal nitrogen level. Correlation analysis showed that nutrient distribution changed under different nitrogen treatments. There was a negative correlation between leaf traits and root biomass under normal nitrogen level, however, the correlation became positive in low nitrogen treatment. Moreover, with the decrease of nitrogen level, the negative correlation between leaf morphology and chlorophyll levels became weakened. The growth of the genotypes under the two treatments was evaluated by combining principal component analysis with a fuzzy mathematical membership function; the results showed that leaf traits accounted for a large proportion of the variation in the evaluation model. According to the results of comprehensive evaluation of plants under the two treatments, the 338 P. deltoides genotypes could be divided into nine categories, with wide genotypic diversity in nitrogen use efficiency and low nitrogen tolerance. As a result, 26 N-efficient genotypes and 24 N-inefficient genotypes were selected. By comparative analysis of their morphological and physiological traits under the two treatments, leaf traits could be significant indicators for nitrogen use efficiency and nitrogen tolerance, which is of considerable significance for breeding poplar varieties with high nitrogen use efficiencies.

scholarly journals Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

2017 ◽  
Vol 14 (24) ◽  
pp. 5693-5704 ◽  
Author(s):  
Gabriella M. Weiss ◽  
Eva Y. Pfannerstill ◽  
Stefan Schouten ◽  
Jaap S. Sinninghe Damsté ◽  
Marcel T. J. van der Meer
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Emiliania Huxleyi ◽  
High Light Intensity ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Long Chain

Abstract. Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

scholarly journals Design of an IoT based Real Time Environment Monitoring System using Legacy Sensors

2018 ◽  
Vol 210 ◽  
pp. 03008
Author(s):  
Aparajita Das ◽  
Manash Pratim Sarma ◽  
Kandarpa Kumar Sarma ◽  
Nikos Mastorakis
Keyword(s):  
Air Pollution ◽  
Light Intensity ◽  
Real Time ◽  
Environmental Conditions ◽  
Low Cost ◽  
Environment Monitoring ◽  
Time Data ◽  
Graphical Information ◽  
Real Time Data ◽  
Sun Light

This paper describes the design of an operative prototype based on Internet of Things (IoT) concepts for real time monitoring of various environmental conditions using certain commonly available and low cost sensors. The various environmental conditions such as temperature, humidity, air pollution, sun light intensity and rain are continuously monitored, processed and controlled by an Arduino Uno microcontroller board with the help of several sensors. Captured data are broadcasted through internet with an ESP8266 Wi-Fi module. The projected system delivers sensors data to an API called ThingSpeak over an HTTP protocol and allows storing of data. The proposed system works well and it shows reliability. The prototype has been used to monitor and analyse real time data using graphical information of the environment.

In vitro studies on the induction of sporogenous tissue on leaves of cinnamon fern. I. Environmental factors

1972 ◽  
Vol 50 (12) ◽  
pp. 2673-2682 ◽  
Author(s):  
William H. Harvey ◽  
James D. Caponetti
Keyword(s):  
Environmental Factors ◽  
Light Intensity ◽  
Environmental Conditions ◽  
Light Exposure ◽  
Progressive Increase ◽  
Light Phase ◽  
Sporogenous Tissue ◽  
Light Darkness

Intact, set III, cinnamon fern cataphyll and frond primordia, which were shown to have no predisposition to fertility in situ, produced sporangia when excised and cultured under sterile conditions in Knudson's medium supplemented with various levels of sucrose and maintained on 11 different regimens of light, darkness, and temperature for 10 weeks. Increasing levels of sucrose resulted in increased fertility under all environmental conditions, but the highest percentage of fertility was obtained under conditions of continuous dark at 26 °C. As the length of the light phase of the photoperiods decreased, a progressive increase in induction of fertile leaves was observed, suggesting that periods of long light exposure are inhibitory to the initiation of sporangia. Conversely, as the light intensity was increased, an inhibition of sporophyll differentiation occurred. Sporangia excised from dark-induced sporophylls and cultured in the light produced viable spores which germinated yielding haploid gametophytes that ultimately produced sporophytes.

Potensi Penyebaran Covid-19 di Objek Wisata Indoor Sumatera Barat Berdasarkan Kualitas Fisik Udara Studi Kasus: Lubang Japang dan Istano Basa Pagaruyung

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Resti Ayu Lestari ◽  
Rinda Andhita Regia ◽  
Hafifatul Auliya Rahmy ◽  
Vezy Hidayatifa Thayyibah ◽  
Nadya Fadhillah Febrinaldi
Keyword(s):  
Air Quality ◽  
Light Intensity ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Environmental Conditions ◽  
Interview Methods ◽  
West Sumatra ◽  
Research Objects ◽  
Pm2.5 Concentration

The Covid-19 pandemic is affecting indoor tourism in West Sumatra. The spread of a virus through could be influenced by indoor air quality. This study aims to analyze the potensial spread of Covid-19 in the indoor tourism in West Sumatra based on the physical indoor air quality, including PM2.5 concentration, temperature, humidity, and light intensity. The research objects were Lubang Japang Bukittinggi and Istano Basa Pagaruyung. The research was conducted by using sampling and interview methods. The data obtained were compared to Permenkes No. 1077/Menkes/Per/V/2011 and the suitable environmental conditions for the virus. The results showed that the temperature values in tourist objects were below the standards used. The temperature value in the research objects ranged from 20oC to 30oC. The humidity, light intensity, and PM2.5 concentration values were outside the ranges stipulated by regulations. Lubang Japang humidity was: 75.97 - 94.76 Rh; Istano Basa Pagaruyung: 65.83 - 67.16 Rh. Lubang Japang light intensity was: 0.4 - 4.0 Lux; Istano Basa Pagaruyung: 28 - 38 Lux. The concentration of PM2.5 at Lubang Japang: 187.45 µg / Nm3; Istano Basa Pagaruyung: 77.29 µg / Nm3. Based on this research, the humidity and the PM2.5 concentration of the research objects have the potential to spread the Covid-19.

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