scholarly journals Analysis of septal spacing and septal crowding in Devonian and Carboniferous ammonoids

2021 ◽  
Vol 140 (1) ◽  
Author(s):  
Sophie Marie Beck ◽  
Kenneth De Baets ◽  
Christian Klug ◽  
Dieter Korn
Keyword(s):  
Environmental Conditions ◽  
Growth Stages ◽  
Ontogenetic Variation ◽  
Common Phenomenon ◽  
Ecological Conditions

AbstractSeptal crowding is widely known as a sign of maturity in conchs of ammonoids and nautiloids. However, reduced septal spacing may also occur as a consequence of adverse ecological conditions. Here, we address the question how septal spacing varied through ontogeny in representatives of some of the major clades of Devonian and Carboniferous ammonoids. We found that the degree of ontogenetic variation is similar between clades and that variation is only weakly linked with conch form. The results show that septal crowding alone is insufficient to identify adulthood in ammonoids; intermediate septal crowding is a common phenomenon and occurs in various growth stages. Changes in septal distances during ontogeny were, in addition to adulthood of the individuals, a passive reaction likely caused by fluctuating environmental conditions.

Sensitivity cycling and its ecological role in seeds with physical dormancy

2009 ◽  
Vol 19 (1) ◽  
pp. 3-13 ◽  
Author(s):  
K.M.G. Gehan Jayasuriya ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Environmental Conditions ◽  
Common Phenomenon ◽  
Ecological Role ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Seed Coats

AbstractCycling of physically dormant (PY) seeds between states insensitive and sensitive to dormancy-breaking factors in the environment has recently been demonstrated inFabaceaeandConvolvulaceae, and it may be a common phenomenon in seeds with water-impermeable seed coats. In contrast to seeds of many species with physiological dormancy (PD), those with PY cannot cycle between dormancy and non-dormancy (ND). In this paper, we evaluate the role of sensitivity cycling in controlling the timing of germination of seeds with PY in nature, and show that sensitivity cycling in seeds with PY serves the same ecological role as dormancy cycling in seeds with PD. Thus, sensitivity cycling in seeds with PY ensures that germination in nature occurs only at (a) time(s) of the year when environmental conditions for growth are, and are likely to remain, suitable long enough for the plant to complete its life cycle or to form a perennating structure. Further, we describe the experimental procedures necessary to determine whether sensitivity cycling is occurring, and discuss briefly the possible relevance of sensitivity cycling to dormancy classification.

scholarly journals The effect of domestication on post-conflict management: wolves reconcile while dogs avoid each other

2018 ◽  
Vol 5 (7) ◽  
pp. 171553 ◽  
Author(s):  
Simona Cafazzo ◽  
Sarah Marshall-Pescini ◽  
Martina Lazzaroni ◽  
Zsófia Virányi ◽  
Friederike Range
Keyword(s):  
Conflict Management ◽  
Environmental Conditions ◽  
Domestic Dogs ◽  
Ecological Conditions ◽  
Functional Relationships ◽  
Social Species ◽  
Post Conflict ◽  
Latency Duration

Highly cooperative social species are expected to engage in frequent reconciliation following conflicts in order to maintain pack cohesiveness and preserve future cooperation. By contrast, in social species with low reliance on cooperation, reconciliation is expected to be less frequent. Here, we investigate the pattern of reconciliation in four captive wolf packs and four captive dog packs. We provide evidence for reconciliation in captive wolves, which are highly dependent on cooperation between pack members, while domestic dogs, which rely on conspecific cooperation less than wolves, avoided interacting with their partners after conflicts. Occurrence, intensity, latency, duration and initiation of wolf reconciliations appeared to vary as a consequence of a compromise between the costs (e.g. risk of further aggression) and the benefits (e.g. restoring relationship with opponents) of such interactions. Our results are in line with previous findings on various wolf packs living under different social and ecological conditions, suggesting that reconciliation is an important strategy for maintaining functional relationships and pack cohesiveness. However, current results on dogs are in contrast to the only other study showing that reconciliation can occur also in this species. Therefore, the occurrence of reconciliation in dogs may be influenced by social and environmental conditions more than in wolves. Which factors promote and modulate reconciliation in dogs needs to be further investigated.

Expression and relationships of resistance to white rust (Albugo candida) at cotyledonary, seedling, and flowering stages in Brassica juncea germplasm from Australia, China, and India

2007 ◽  
Vol 58 (3) ◽  
pp. 259 ◽  
Author(s):  
C. X. Li ◽  
K. Sivasithamparam ◽  
G. Walton ◽  
P. Salisbury ◽  
W. Burton ◽  
...  
Keyword(s):  
Plant Growth ◽  
Brassica Juncea ◽  
Environmental Conditions ◽  
Host Resistance ◽  
Growth Stages ◽  
Sources Of Resistance ◽  
Albugo Candida ◽  
White Rust ◽  
China And India ◽  
Canola Quality

White rust (Albugo candida) is a highly destructive disease of oilseed Brassicas such as Brassica juncea and B. rapa. Most commercial B. juncea or B. rapa varieties are highly susceptible and yield losses from combined infection of leaves and inflorescences can be up to 20% or 60% in Australia and India, respectively. In Australia, canola-quality B. juncea has been developed to extend oilseed Brassica production into lower rainfall areas, with the first commercial B. juncea canola-quality variety planned for release in 2006. It is essential to identify useful sources of host resistance in B. juncea as breeding and/or selection of material for resistance is the most cost-effective method of delivering control for farmers. Three experiments were undertaken under controlled-environmental conditions to identify the best methods of characterising host resistance and to identify sources of resistance in B. juncea germplasm from Australia, China, and India. Forty-four B. juncea genotypes, viz. 22 from India, 12 from Australia, and 10 from China, were tested. Four Chinese genotypes (CBJ-001, CBJ-002, CBJ-003, CBJ-004) and one Australian genotype (JR049) consistently showed high resistance to A. candida across the different plant growth stages against a pathotype prevailing in Australia. Similarly, the most susceptible genotypes (viz. Indian genotypes RH781, RL1359, RH819) were extremely susceptible irrespective of the plant growth stage. Overall, although disease severity on cotyledons and leaves at the different growth stages was significantly and positively correlated, there was, however, no significant correlation between the number of stagheads and any of the other disease parameters measured. Our study demonstrates that controlled-environmental conditions are suitable for rapid identification of resistant genotypes and that genotypes with high levels of resistance can be reliably identified at the cotyledonary, seedling, or flowering stages.

Light intensity and the growth of Eucalyptus seedlings. I. Ontogenetic variation in E. fastigata

1970 ◽  
Vol 18 (1) ◽  
pp. 29 ◽  
Author(s):  
RJ Cameron
Keyword(s):  
Enzyme Activity ◽  
Light Intensity ◽  
Morphological Characteristics ◽  
Anatomical Structure ◽  
Growth Stages ◽  
Ontogenetic Variation ◽  
Light Climate ◽  
Low Light ◽  
Adult Leaf ◽  
Abundance And Distribution

Morphological and physiological variation associated with ontogenetic development is described for E. fastigata and their significance in ecology is discussed. Juvenile, intermediate, and adult leaf stages are identified. These differ in such morphological characteristics as leaf orientation, shape, thickness, chlorophyll content, and anatomical structure (including size, abundance, and distribution of stomata), all details which, in juvenile and intermediate leaves at least, are modified by the light climate under which the plants are grown. There are also significant physiological differences between juvenile and intermediate growth stages, particularly as concern apical dominance and rates of apparent photosynthesis, and modification of these by light climate. A comparison of juvenile and intermediate leaves shows that the former possess a number of features which should permit them to function better in conditions of low light intensity but, contrary to such expectations, rates of apparent photosynthesis are higher in intermediate leaves. That this is so is, it is suggested, due to differences in photosynthetic enzyme activity, an hypothesis which has not been investigated.

scholarly journals Monitoring of Black Sea algal viruses Tetraselmis viridis and Phaeodactylum tricornutum in bays of Sevastopol as a component of ecological monitoring of the studied aquatories

2020 ◽  
pp. 139-148
Author(s):  
O.A. Stepanova ◽  
Keyword(s):  
Environmental Conditions ◽  
Phaeodactylum Tricornutum ◽  
Ecological Monitoring ◽  
Ecological Indicator ◽  
Maximum Frequency ◽  
Maximum Difference ◽  
Ecological Conditions ◽  
Algal Viruses ◽  
Tetraselmis Viridis

Virus monitoring is a widespread control of their background circulation. Since 2002, the monitoring of algal viruses that infect microalgae Tetraselmis viridis and Phaeodactylum tricornutum has been carried out in the bays of Sevastopol differing in ecological conditions. The purpose of this work is to analyze and assess the results of this long-term (2002–2020) monitoring. The results obtained with taking into account the exactingness or resistance to environmental conditions of hosts of algal viruses that infect microalgae T. viridis and P. tricornutum were the basis for the following conclusions regarding the ecological well-being of the studied bays of Sevastopol: – relatively favorable ecological conditions in 2007–2008, 2017–2018 and in 2020. (maximum frequency of isolation PtV, and/or minimum TvV, and / or maximum difference in frequency of isolation between PtV and TvV); – unfavorable ecological conditions in 2002–2003, 2006 and 2015 (maximum frequency of isolation TvV, and/or minimum PtV, and/or maximum difference in frequency of isolation between TvV and PtV). Analysis of the monitoring results of algal viruses of T. viridis and P. tricornutum in 2015–2020 revealed that the studied relatively ecologically safe bays are characterized by the maximum number of all isolates of algal viruses (both TvV and PtV) and the numerical predominance of strains of algal virus of P. tricornutum, which is demanding to environmental conditions. At the same time, the minimum amount of all viral isolates was recorded in the ecologically unfavorable bay. The results of a long-term monitoring of algal viruses of T. viridis and P. tricornutum have established the possibility of using the monitoring of marine viruses, in particular of algal viruses of microalgae which are indicative of the ecological situation, as a component of complex ecological monitoring as ecological indicator.

scholarly journals Soil Ciliates of Different Trophic Groups in Samur-Yalama National Park, Azerbaijan

2017 ◽  
Vol 51 (2) ◽  
pp. 175-178
Author(s):  
I. Kh. Alekperov ◽  
V. F. Mamedova
Keyword(s):  
Environmental Conditions ◽  
National Park ◽  
Anthropogenic Impact ◽  
Comparative Investigation ◽  
Trophic Groups ◽  
Soil Environment ◽  
Ecological Conditions ◽  
Soil Ciliates

Abstract A comparative investigation of the ciliates of separate trophic groups on the areas of Samur-Yalama National Park with different strength of anthropogenic impact was carried out. The ratio of trophic groups in the soil ciliates communities was found to reflect the ecological conditions in soil environment. It is expressed primarily in the reduction of the number of trophic groups caused by deteriorating environmental conditions.

scholarly journals Measurement of Environmentally Influenced Variations in Anthocyanin Accumulations in Brassica rapa subsp. Chinensis (Bok Choy) Using Hyperspectral Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Hyo-suk Kim ◽  
Ji Hye Yoo ◽  
Soo Hyun Park ◽  
Jun-Sik Kim ◽  
Youngchul Chung ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Brassica Rapa ◽  
Environmental Conditions ◽  
Imaging System ◽  
Plant Phenotyping ◽  
Growth Stages ◽  
Anthocyanin Accumulation ◽  
Potential Health ◽  
Destructive Analysis ◽  
Leaf Tissues

Dietary supplements of anthocyanin-rich vegetables have been known to increase potential health benefits for humans. The optimization of environmental conditions to increase the level of anthocyanin accumulations in vegetables during the cultivation periods is particularly important in terms of the improvement of agricultural values in the indoor farm using artificial light and climate controlling systems. This study reports on the measurement of variations in anthocyanin accumulations in leaf tissues of four different cultivars in Brassica rapa var. chinensis (bok choy) grown under the different environmental conditions of the indoor farm using hyperspectral imaging. Anthocyanin accumulations estimated by hyperspectral imaging were compared with the measured anthocyanin accumulation obtained by destructive analysis. Between hyperspectral imaging and destructive analysis values, no significant differences in anthocyanin accumulation were observed across four bok choy cultivars grown under the anthocyanin stimulation environmental condition, whereas the estimated anthocyanin accumulations displayed cultivar-dependent significant differences, suggesting that hyperspectral imaging can be employed to measure variations in anthocyanin accumulations of different bok choy cultivars. Increased accumulation of anthocyanin under the stimulation condition for anthocyanin accumulation was observed in “purple magic” and “red stem” by both hyperspectral imaging and destructive analysis. In the different growth stages, no significant differences in anthocyanin accumulation were found in each cultivar by both hyperspectral imaging and destructive analysis. These results suggest that hyperspectral imaging can provide comparable analytic capability with destructive analysis to measure variations in anthocyanin accumulation that occurred under the different light and temperature conditions of the indoor farm. Leaf image analysis measuring the percentage of purple color area in the total leaf area displayed successful classification of anthocyanin accumulation in four bok choy cultivars in comparison to hyperspectral imaging and destructive analysis, but it also showed limitation to reflect the level of color saturation caused by anthocyanin accumulation under different environmental conditions in “red stem,” “white stem,” and “green stem.” Finally, our hyperspectral imaging system was modified to be applied onto the high-throughput plant phenotyping system, and its test to analyze the variation of anthocyanin accumulation in four cultivars showed comparable results with the result of the destructive analysis.

scholarly journals Adaptability studies of garlic (Allium sativum) advanced lines

1970 ◽  
pp. 19-21
Author(s):  
Asfand Raheel ◽  
Hidayatullah, Raheel Babar ◽  
Muhammad Arshad Ullah ◽  
Ali Zaffar, Maouz Iqbal
Keyword(s):  
Plant Height ◽  
Environmental Conditions ◽  
Allium Sativum ◽  
Leaf Number ◽  
Leaf Width ◽  
Growth Stages ◽  
Morphological Parameters ◽  
And Control ◽  
Different Growth Stages

The purpose of this research was to identify the most desirable verities adopted in different environmental conditions of the country. Five garlic advance line; NARC Garlic-1, NARC Garlic-3, NARC Garlic-4, NARC Garlic-5 along with ‘Lehsan Gulabi’ as check were evaluated at different locations along with NARC, Islamabad. Different morphological parameters; plant height, plant girth, leaf number per plant and leaf width were studied at four different growth stages. NARC Garlic-1 performed better as compared other advance lines and control tested.

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