scholarly journals 397 LIFE CYCLE AND FLORAL INITIATION OF ORNAMENTAL ALLIUM SPECIES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 488b-488
Author(s):  
Rina Kamenetsky ◽  
Jacob Blaustein
Keyword(s):  
Life Cycle ◽  
Mediterranean Area ◽  
Flower Formation ◽  
Floral Initiation ◽  
Annual Life Cycle ◽  
Allium Species ◽  
Inflorescence Development ◽  
Principal Mechanism ◽  
Flower Primordia ◽  
Central Asian

The annual life cycle and development of the monocarpic shoot of some ornamental Allium species from Central Asia and the Mediterranean area have been followed from the time of meristem dome initiation in the axil of a mother plant leaf, through formation of scale, leaf and flower primordia. There are three periods of meristem activity from apex initiation to flower formation. Detailed analysis of inflorescence development has been carried out by Scanning Electronic Microscope (SEM). The life span of the Allium monocarpic shoot can be as long as 18 months. Climatic variations between Central Asian and Mediterranean areas lead to differences in the time of leaf sprout and flowering of species from the same taxonomic group. The principal mechanism of floral initiation is similar for species from both areas. Knowledge of the structure and development of the shoot will be useful for improvement of an optimal program of ornamental Allium cultivation.

Temporal variation in the weight-size relationship of the mangrove crab Ucides cordatus L. (Decapoda: Ucididae) in relation to its life cycle phases

2014 ◽  
Vol 64 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Marcos de Miranda Leão Leite ◽  
Cynthia Yuri Ogawa ◽  
Carla Ferreira Rezende ◽  
José Roberto Feitosa Silva
Keyword(s):  
Life Cycle ◽  
Condition Factor ◽  
River Estuary ◽  
Total Weight ◽  
Northeastern Brazil ◽  
Annual Life Cycle ◽  
Ucides Cordatus ◽  
Mangrove Crab ◽  
Significant Difference ◽  
The Relationship

The relationship between weight and size of individuals can be used to evaluate the status of a population, which is particularly useful for natural populations that are being exploited. Ucides cordatus occurs on the Atlantic coast of the American continent, from Florida (USA) to Santa Catarina (Brazil). This species is economically very important, most of all in the Northeastern area of Brazil, as well as in the Dominican Republic and Suriname. The objective of this study was to analyze life phases (‘fattening’, ‘matumba’, ‘milk-crab’, ‘maturation’ and ‘walking’) by use of the weight-length relationships, as well as temporal variations in this condition factor for each sex of U. cordatus. For this purpose, individuals were sampled monthly for twenty-four months at the Jaguaribe River estuary, Ceará State, Northeastern Brazil. The relationship between total weight and cephalothorax width was established using regression analysis, adjusted by a power equation. The dynamics of the condition factor were analyzed for each sex using the variation of its averages related to annual life cycle; this was done for each of the previously-mentioned phases. The relationship between total weight and cephalothorax width showed an isometric growth in males and negative allometric growth in females suggesting that, for the same reference size, males are heavier than females. When considering the average of the female condition factors, these were greater than those for males during the annual life cycle, except during the ‘maturation’ phase, which is the phase with a higher demand of energetic reserves for males. Annual variation of the condition factor in females presented no significant difference.

Environmental and Genetic Control of Reproduction in Danthonia caespitosa Populations

1978 ◽  
Vol 26 (3) ◽  
pp. 351 ◽  
Author(s):  
KC Hodgkinson ◽  
JA Quinn
Keyword(s):  
Floral Induction ◽  
Flag Leaf ◽  
Day Length ◽  
Herbarium Specimens ◽  
Floral Initiation ◽  
Inflorescence Development ◽  
Southern Limit ◽  
The North ◽  
Eastern Australia ◽  
Controlled Environments

Seedlings and older plants of five populations of Danthonia caespitosa from south-eastern Australia were grown in controlled environments and in a transplant garden to determine the effect of day length, temperature, and vernalization of floral initiation and inflorescence development. The populations were selected from widely separated sites which spanned the latitudinal range (31-42°S.) for the species and extended from a hot, semiarid environment in the north to a relatively cool and moist temperature environment in the south. Examination of herbarium specimens indicated that seed set could occur as early as mid September at the northern limit for the species and not before mid January at the southern limit (Tasmania). In a uniform transplant garden located at Deniliquin (latitude 35° 23′S.) plants from the northern site reached anthesis 4 weeks earlier than plants from southern sites. Controlled environment experiments revealed that D. caespitosa is a long-day plant. Northern populations required a 9 . 5 hr day length or longer for floral induction compared with 11 hr or longer for southern populations. The number of days in inductive conditions (outside, day length 13.5 hr) required for floral initiation was 5-7 for the three most northern populations and 21-25 days for the two southern populations. Inflorescence development (initiation to flag leaf stage) was considerably slower in southern populations. All but the most northern population responded to vernalization. Flowering was earlier in temperatures that were optimal for plant growth. At high temperatures (36/31°C day/night) flowering was not significantly delayed for the three most northern populations, but was for the two southern populations, and florets contained caryopses in only the three northern populations. These results suggest that in cool and moist temperate habitats reproduction of this species is programmed by day length and temperature effects on floral initiation and development to coincide with a predictable growing season, whereas in hot semiarid habitats this control is relaxed, which permits opportunistic reproduction whenever soil moisture and temperature permit growth.

Changes in migration, carry-over effects, and migratory connectivity

2019 ◽  
pp. 93-107 ◽  
Author(s):  
Roberto Ambrosini ◽  
Andrea Romano ◽  
Nicola Saino
Keyword(s):  
Climate Change ◽  
Life Cycle ◽  
Population Size ◽  
Migratory Connectivity ◽  
Negative Effects ◽  
Annual Life Cycle ◽  
Northern Latitudes ◽  
Timing Of Migration ◽  
Tropical Areas ◽  
Carry Over

Studies of the timing (phenology) of bird migration provided some of the first evidence for the effects of climate change on organisms. Since the rate of climate change is uneven across the globe, with northern latitudes experiencing faster warming trends than tropical areas, animals moving across latitudes are subject to diverging trends of climate change at different stages of their annual life cycle, and, consequently, they can become mistimed with the local ecological conditions, with potentially negative effects on population size. This chapter reviews the modifications induced by climate change in different migration traits, like the timing of migration events, the distribution of organisms, and the direction and the speed of movements. It also considers the effects of ecological carry-over effects and migratory connectivity on the response of birds to climate change.

A taxonomic review of the Margarodoid genus Stigmacoccus Hempel  (Hemiptera: Sternorrhyncha: Coccoidea: Stigmacoccidae), with some details on their biology

Zootaxa ◽  
2007 ◽  
Vol 1507 (1) ◽  
pp. 1-55 ◽  
Author(s):  
CHRIS HODGSON ◽  
HEATHER GAMPER ◽  
AMAURI BOGO ◽  
GILLIAN WATSON
Keyword(s):  
Life Cycle ◽  
Scale Insect ◽  
Present Knowledge ◽  
Passerine Birds ◽  
Adult Males ◽  
Undescribed Species ◽  
Annual Life Cycle ◽  
Honey Production ◽  
Adult Females ◽  
The Family

Stigmacoccus is an unusual scale insect genus from Central and South America that has been little studied. It belongs to the family Stigmacoccidae within the archaeococcoid group of genera which used to comprise the family Margarodidae (Morrison, 1927) but which are now considered to represent at least 9 families. The present paper describes or redescribes the adult females, adult males, cyst stages and crawlers of the three known species (S. asper, S. garmilleri, and S. paranaensis), plus the prepupa of S. garmilleri and S. paranaensis, and (briefly), the pupa of S. paranaensis. It is considered that the female has two cyst stage instars; the number in the male is uncertain. Adult female S. asper and S. paranaensis appear to have groups of loculate pores on the walls of the vagina. A lectotype for S. asper is designated. In addition, cyst stages of three further undescribed species are described (but not formally named) and illustrated. Some observations on the biology and life cycle are also included. The honeydew of Stigmacoccus species has been shown to be an important energy source for overwintering passerine birds which defend this resource. A summary of our present knowledge is presented, including how the honedew is eliminated (through a long anal tube) and details are given with regard to rates of honeydew flow, sugar concentration, cyst densities and annual timing of peak flows. The annual life cycle, as far as it is known, is discussed. It is concluded that this honeydew could be economically important as a source of sugar for honey production but this would need to be carefully managed to maintain an ecological balance.

Vegetative Propagation of Species of Genus Allium L.

1993 ◽  
Vol 27 (7-8) ◽  
pp. 511-517
Author(s):  
Rina Kamenetsky
Keyword(s):  
Life Cycle ◽  
Vegetative Propagation ◽  
Genetic Stability ◽  
Vegetative Reproduction ◽  
Natural Populations ◽  
Morphological Type ◽  
Useful Plants ◽  
Allium Species ◽  
Apical Buds ◽  
Arid Conditions

The genus Allium L. consists of about 500 species in the Northern hemisphere and includes a large number of useful plants. The highly variable underground organs of Allium species - rhizomes and bulbs - have the function of storing food and moisture in severe environmental conditions. Their other very important function - vegetative reproduction and propagation - increases the chances of survival and supports the genetic stability of natural populations. Among about 40 species studied, 5 types of vegetative reproduction and propagation are distinguishable. The formation of apical buds, daughter bulblets, stolons and apomictic bulblets in the inflorescense have been observed. There is possibly some connection between vegetative propagation, morphological type and life cycle. The process of evolution within the genus and the migration of species to arid conditions lead possibly to the appearance in phylogenesis of prevalence of seminal reproduction over vegetative propagation.

scholarly journals On the life-cycle of ameles spallanzania (Rossi, 1792) (Insecta, Mantodea)

2011 ◽  
Vol 152 (1) ◽  
pp. 25
Author(s):  
Roberto Battiston ◽  
Carlo Galliani
Keyword(s):  
Life Cycle ◽  
Mediterranean Area ◽  
Climatic Conditions ◽  
Northern Italy ◽  
General Distribution ◽  
Continental Area ◽  
The Mediterranean ◽  
Behavioural Strategies

The recent find of an <em>Ameles spallanzania</em> population in a continental area of northern Italy permitted to redraw the northernmost edge of the distribution of this species and to study its life cycle in extreme climatic conditions. A comparison with collecting records of adult specimens from the Mediterranean area has been performed to put in evidence how this species adapts its life-cycle timings in different latitudes: hatching earlier or using nymphs to overwinter in warmer localities or oothecae in colder ones. Overwintering strategies of <em>Ameles spallanzania</em> have been compared with strategies of other genera of mantids that share the same habitat but have different life-cycle strategies and general distribution. Different developing times in mantids seem to be linked to behavioural strategies more than physiological attitudes.

Long-term effects of 2,4-D application on plants. II. Herbicide avoidance by Chenopodium album and Thlaspi arvense

1988 ◽  
Vol 66 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Larry Hume
Keyword(s):  
Life Cycle ◽  
Chenopodium Album ◽  
Herbicide Tolerance ◽  
Long Term Effects ◽  
Annual Life Cycle ◽  
Thlaspi Arvense ◽  
Immature Seeds ◽  
Winter Annual ◽  
Dichlorophenoxy Acetic Acid

Research plots in a wheat–wheat–fallow rotation at Indian Head, Sask., were sprayed annually with 2,4-dichlorophenoxy-acetic acid (2,4-D) for 36 consecutive years. Two species susceptible to 2,4-D, Chenopodium album L. and Thlaspi arvense L., were dominant in these plots. From 1981 to 1983, C. album and T. arvense seedlings that emerged during four periods of the growing season were marked and their mortality, seed production, and size recorded. From these data and other studies, 10 ways in which C. album and T. arvense managed to survive herbicide application were identified. These are intermittent germination, herbicide tolerance, small size of late-emerging seedlings, short life cycle, hardiness, failure of control practices, long-term dormancy, seed dispersal, viability of immature seeds, and winter annual life cycle of T. arvense.

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