Ecology of a forest weed of Newfoundland: vegetative regeneration strategy of Kalmia angustifolia

1993 ◽  
Vol 71 (1) ◽  
pp. 161-166 ◽  
Author(s):  
A. U. Mallik
Keyword(s):  
Growing Season ◽  
Regeneration Strategy ◽  
Stem Base ◽  
Kalmia Angustifolia ◽  
Vegetative Regeneration ◽  
Large Numbers ◽  
Below Ground ◽  
Vegetative Spread ◽  
First Time ◽  
Ground Structures

The vegetative regeneration characteristics of Kalmia angustifolia were studied by examining the near ground and below-ground structures of the plant. Three methods of vegetative regeneration were observed in Kalmia: layering, stem-base sprouting, and rhizomatous growth, which make the plant more resilient than other ericaceous plants of similar stature following disturbance. Layering occurred only in tall old Kalmia of undisturbed habitats. Stem-base sprouting and rhizomatous growth were found to be the most common and most effective modes of vegetative regeneration. These methods were common in both disturbed and undisturbed habitats. Three types of rhizome systems, namely primary, secondary, and tertiary rhizomes, were identified and described for the first time in Kalmia. Secondary rhizomes were found to be the most effective organ for vegetative spread of the plant. Some secondary rhizomes may grow more than 1 m in one growing season. A 5-year-old Kalmia may produce, on average, 36 secondary rhizomes with a total length of 750 cm. Secondary rhizomes of Kalmia first grow horizontally, then come aboveground growing vertically and exhibiting apical dominance. Large numbers of dormant vegetative buds (three at each node) and adventitious roots are produced at the rhizome nodes. Transverse sections of current-year rhizome showed many trichomes. The cells of the pith are thick-walled and are characterized by large lysigenous cavities. The anatomy of axillary buds and leaf primordia of the aboveground stems of Kalmia were similar to buds and bud scales of the rhizome. Key words: Kalmia, disturbance, fire, regeneration strategy, rhizome, trichomes.

scholarly journals Effect of thinning intensity on understory herbaceous diversity and biomass in mixed coniferous and broad-leaved forests of Changbai Mountain

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Gerong Wang ◽  
Yue Sun ◽  
Mo Zhou ◽  
Naiqian Guan ◽  
Yuwen Wang ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Mixed Forest ◽  
Growing Season ◽  
Total Biomass ◽  
Herb Layer ◽  
Simpson Index ◽  
Thinning Intensity ◽  
Ground Biomass ◽  
Below Ground ◽  
Understory Herb

Abstract Background Herbs are an important part of the forest ecosystem, and their diversity and biomass can reflect the restoration of vegetation after forest thinning disturbances. Based on the near-mature secondary coniferous and broad-leaved mixed forest in Jilin Province Forestry Experimental Zone, this study analyzed seasonal changes of species diversity and biomass of the understory herb layer after different intensities of thinning. Results The results showed that although the composition of herbaceous species and the ranking of importance values were affected by thinning intensity, they were mainly determined by seasonal changes. Across the entire growing season, the species with the highest importance values in thinning treatments included Carex pilosa, Aegopodium alpestre, Meehania urticifolia, and Filipendula palmata, which dominated the herb layer of the coniferous and broad-leaved mixed forest. The number of species, Margalef index, Shannon-Wiener index and Simpson index all had their highest values in May, and gradually decreased with months. Pielou index was roughly inverted “N” throughout the growing season. Thinning did not increase the species diversity. Thinning can promote the total biomass, above- and below-ground biomass. The number of plants per unit area and coverage were related to the total biomass, above- and below-ground biomass. The average height had a significantly positive correlation with herb biomass in May but not in July. However, it exerted a significantly negative correlation with herb biomass in September. The biomass in the same month increased with increasing thinning intensity. Total herb biomass, above- and below-ground biomass showed positive correlations with Shannon-Winner index, Simpson index and Pielou evenness index in May. Conclusions Thinning mainly changed the light environment in the forest, which would improve the plant diversity and biomass of herb layer in a short time. And different thinning intensity had different effects on the diversity of understory herb layer. The findings provide theoretical basis and reference for reasonable thinning and tending in coniferous and broad-leaved mixed forests.

The habits and habitats of the opisthobranch molluscs of the British Solomon Islands

1969 ◽  
Vol 255 (800) ◽  
pp. 541-548 ◽  
Keyword(s):  
Natural History ◽  
Solomon Islands ◽  
Gut Contents ◽  
Numerical Evidence ◽  
Large Numbers ◽  
Different Types ◽  
Opisthobranch Molluscs ◽  
First Time ◽  
Reef Formation

Often bizarre in shape and gaudily coloured, the opisthobranchs of the tropical IndoPacific have always been attractive subjects for the specialist worker and for writers of popular natural history. There is certainly no lack of papers describing their anatomy and systematics (Marcus & Burch (1965) give a fairly full bibliography), but only in those by Risbec (1928 a, b , 1951, 1953) are there descriptions of where or how they live and his statements are brief and rather vague. I collected opisthobranchs so as to record them for the British Solomon Islands for the first time and, whenever possible, I noted their habits and habitats. My observations on gut contents are rather scanty as I did not wish to damage any of the few specimens of each species collected. From an examination of ten different types of reef formation I discovered that opisthobranchs are common in only two places; (1) the crest of a semi-exposed reef where algae occur in pools, and (2) the flat of a sheltered or semi-sheltered reef. At each of these sites several distinct habitats can be distinguished. Unfortunately my recognition of these habitats is not supported by strong numerical evidence as none of the 55 species occurred in large numbers.

scholarly journals Interannual Variation in Root Production in Grasslands Affected by Artificially Modified Amount of Rainfall

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Karel Fiala ◽  
Ivan Tůma ◽  
Petr Holub
Keyword(s):  
Interannual Variation ◽  
Plant Biomass ◽  
Growing Season ◽  
Lower Amount ◽  
Root Production ◽  
Climate Scenarios ◽  
Natural Rainfall ◽  
Plant Matter ◽  
Grassland Ecosystems ◽  
Below Ground

The effect of different amounts of rainfall on the below-ground plant biomass was studied in three grassland ecosystems. Responses of the lowland (dryFestucagrassland), highland (wetCirsiumgrassland), and mountain (Nardusgrassland) grasslands were studied during five years (2006–2010). A field experiment based on rainout shelters and gravity irrigation simulated three climate scenarios: rainfall reduced by 50% (dry), rainfall increased by 50% (wet), and the natural rainfall of the current growing season (ambient). The interannual variation in root increment and total below-ground biomass reflected the experimentally manipulated amount of precipitation and also the amount of current rainfall of individual years. The effect of year on these below-ground parameters was found significant in all studied grasslands. In comparison with dryFestucagrassland, better adapted to drought, submontane wetCirsiumgrassland was more sensitive to the different water inputs forming rather lower amount of below-ground plant matter at reduced precipitation.

scholarly journals Методы оценки продуктивности представителей рода эхинацея (Echinacea Moench) прегенеративного периода онтогенеза

2013 ◽  
pp. 24-30
Author(s):  
С. В. Поспелов
Keyword(s):  
Regression Models ◽  
Input Data ◽  
Growing Season ◽  
Echinacea Purpurea ◽  
System Productivity ◽  
Aerial Parts ◽  
Purple Coneflower ◽  
Echinacea Pallida ◽  
First Time

За багаторічними дослідженнями ехінацеї пурпурової (Echinacea purpurea (L.) Moench,) сорту Зірка Миколи Вавилова та ехінацеї блідої (Echinacea pallida (Nutt.) Nutt.) сорту Красуня Прерій вперше розроблені й запатентовані методи визначення продуктивності рослин прегенеративного періоду онтогенезу. Методики засновані на регресійних моделях із високими коефіцієнтами детермінації, на підставі яких можна без пошкодження рослин провести оцінку продуктивності надземної частини та кореневої системи протягом веґетаційного періоду. Вихідними даними для розрахунків слугують показники довжини і ширини листковоїпластинки, їх кількість, а також сума температур вище 5 0С і кількість діб від сівби. On the basis of long-term researches of Purple Coneflower (Echinacea purpurea (L.) Moench) variety «Zirka Mykoly Vavylova» and Pale Coneflower (Echinacea pallida (Nutt.) variety «Krasunja Preriy» for the first time ever there were developed and patented the methods for determining the efficiency of plants in pregenesic period of ontogeny. The foundation of methodology was made on the studies of regression models with high coefficients of determination which allow to make the estimation of aerial parts and root system productivity for the whole growing season without damaging the plants. The input data for the calculation are the indicators of the length and width of the leaf blade, the amount and the sum of temperatures above + 5 ºC and the number of days from sowing.

scholarly journals Multi-dimensional leaf phenotypes reflect root system genotype in grafted grapevine over the growing season

GigaScience ◽  
2021 ◽  
Vol 10 (12) ◽  
Author(s):  
Zachary N Harris ◽  
Mani Awale ◽  
Niyati Bhakta ◽  
Daniel H Chitwood ◽  
Anne Fennell ◽  
...  
Keyword(s):  
Root System ◽  
Experimental System ◽  
Growing Season ◽  
Plant Biology ◽  
Shoot System ◽  
Distinct Individual ◽  
Below Ground ◽  
Ground Effects ◽  
Horticultural Practice ◽  
Broad Understanding

Abstract Background Modern biological approaches generate volumes of multi-dimensional data, offering unprecedented opportunities to address biological questions previously beyond reach owing to small or subtle effects. A fundamental question in plant biology is the extent to which below-ground activity in the root system influences above-ground phenotypes expressed in the shoot system. Grafting, an ancient horticultural practice that fuses the root system of one individual (the rootstock) with the shoot system of a second, genetically distinct individual (the scion), is a powerful experimental system to understand below-ground effects on above-ground phenotypes. Previous studies on grafted grapevines have detected rootstock influence on scion phenotypes including physiology and berry chemistry. However, the extent of the rootstock's influence on leaves, the photosynthetic engines of the vine, and how those effects change over the course of a growing season, are still largely unknown. Results Here, we investigate associations between rootstock genotype and shoot system phenotypes using 5 multi-dimensional leaf phenotyping modalities measured in a common grafted scion: ionomics, metabolomics, transcriptomics, morphometrics, and physiology. Rootstock influence is ubiquitous but subtle across modalities, with the strongest signature of rootstock observed in the leaf ionome. Moreover, we find that the extent of rootstock influence on scion phenotypes and patterns of phenomic covariation are highly dynamic across the season. Conclusions These findings substantially expand previously identified patterns to demonstrate that rootstock influence on scion phenotypes is complex and dynamic and underscore that broad understanding necessitates volumes of multi-dimensional data previously unmet.

The Patterns of Large Numbers

2019 ◽  
pp. 43-66
Author(s):  
Steven J. Osterlind
Keyword(s):  
Probability Theory ◽  
Central Limit Theorem ◽  
Limit Theorem ◽  
French Revolution ◽  
Central Limit ◽  
Historical Context ◽  
Binomial Theorem ◽  
The Central Limit Theorem ◽  
Large Numbers ◽  
First Time

This chapter advances the historical context for quantification by describing the climate of the day—social, cultural, political, and intellectual—as fraught with disquieting influences. Forces leading to the French Revolution were building, and the colonists in America were fighting for secession from England. During this time, three important number theorems came into existence: the binomial theorem, the law of large numbers, and the central limit theorem. Each is described in easy-to-understand language. These are fundamental to how numbers operate in a probability circumstance. Pascal’s triangle is explained as a shortcut solving some binomial expansions, and Jacob Bernoulli’s Ars Conjectandi, which presents the study of measurement “error” for the first time, is discussed. In addition, the central limit theorem is explained in terms of its relevance to probability theory, and its utility today.

Below-ground structures

2017 ◽  
pp. 183-202
Author(s):  
Malcolm Millais
Keyword(s):  
Below Ground ◽  
Ground Structures

scholarly journals Particle precipitations during NEIAL events: simultaneous ground based observations at Svalbard

2007 ◽  
Vol 25 (6) ◽  
pp. 1323-1336 ◽  
Author(s):  
J. Lunde ◽  
B. Gustavsson ◽  
U. P. Løvhaug ◽  
D. A. Lorentzen ◽  
Y. Ogawa
Keyword(s):  
Minimum Energy ◽  
Soft Particle ◽  
Particle Precipitation ◽  
Characteristic Energy ◽  
Incoherent Scatter ◽  
Large Numbers ◽  
All Optical ◽  
Ion Acoustic ◽  
Scatter Spectrum ◽  
First Time

Abstract. In this paper we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar (ESR). For the first time, long sequences of NEIALs are recorded, with more than 50 events within an hour, ranging from 6.4 to 140 s in duration. The events took place from ~08:45 to 10:00 UT, 22 January 2004. We combine ESR data with observations of optical aurora by a meridian scanning photometer at wavelengths 557.7, 630.0, 427.8, and 844.6 nm, as well as records from a magnetometer and an imaging riometer. The large numbers of observed NEIALs together with these additional observations, enable us to characterise the particle precipitation during the NEIAL events. We find that the intensities in all optical lines studied must be above a certain level for the NEIALs to appear. We also find that the soft particle precipitation is associated with the down-shifted shoulder in the incoherent scatter spectrum, and that harder precipitation may play a role in the enhancement of the up-shifted shoulder. The minimum energy flux during NEIAL events found in this study was ~3.5 mW/m2 and minimum characteristic energy around 50 eV.

The Demographic Transition Theory of War: Why Young Societies Are Conflict Prone and Old Societies Are the Most Peaceful

2019 ◽  
Vol 43 (3) ◽  
pp. 53-95 ◽  
Author(s):  
Deborah Jordan Brooks ◽  
Stephen G. Brooks ◽  
Brian D. Greenhill ◽  
Mark L. Haas
Keyword(s):  
Young People ◽  
Total Population ◽  
Empirical Examination ◽  
Demographic Transitions ◽  
The Road ◽  
Large Numbers ◽  
The World ◽  
Theory Of War ◽  
First Time

The world is experiencing a period of unprecedented demographic change. For the first time in human history, marked disparities in age structures exist across the globe. Around 40 percent of the world's population lives in countries with significant numbers of elderly citizens. In contrast, the majority of the world's people live in developing countries with very large numbers of young people as a proportion of the total population. Yet, demographically, most of the world's states with young populations are aging, and many are doing so quickly. This first-of-its kind systematic theoretical and empirical examination of how these demographic transitions influence the likelihood of interstate conflict shows that countries with a large number of young people as a proportion of the total population are the most prone to international conflict, whereas states with the oldest populations are the most peaceful. Although societal aging is likely to serve as a force for enhanced stability in most, and perhaps all, regions of the world over the long term, the road to a “demographic peace” is likely to be bumpy in many parts of the world in the short to medium term.

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