scholarly journals Plasticity and the genetics of reproductive behaviour in the monocarpic perennial, Lobelia inflata (Indian tobacco)

Heredity ◽  
2000 ◽  
Vol 85 (4) ◽  
pp. 356-365 ◽  
Author(s):  
Andrew M Simons ◽  
Mark O Johnston
2014 ◽  
Vol 2 (4) ◽  
pp. 1300096 ◽  
Author(s):  
P. William Hughes ◽  
Allison F. Jaworski ◽  
Corey S. Davis ◽  
Susan M. Aitken ◽  
Andrew M. Simons

2013 ◽  
Vol 14 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Viktor VOJNICH ◽  
Ákos MÁTHÉ ◽  
Éva SZŐKE ◽  
Péter BÁNYAI ◽  
Ferenc KAJDI ◽  
...  

Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Meiqin QI ◽  
Mahesh K. Upadhyaya ◽  
Roy Turkington

The reproductive characteristics of natural populations of meadow salsify were monitored between May 1990 and October 1991. Plants in even-aged populations did not produce seeds prior to the second winter and plants in uneven-aged populations died after seed production suggesting that meadow salsify at this site is a monocarpic perennial and not a true biennial. Delayed seed production may enhance abundance of this species by increasing the size of its bud bank. Plants of uneven-aged populations flowered over a range of root crown diameters; the percentage of plants bearing flowers increased with increasing root crown diameters. The minimum root crown diameter at which plants flowered in 1990 and 1991 was 0.2 and 0.6 cm respectively demonstrating that factor(s) other than plant size regulate flowering in this species. Seed production ranged between 100 to 850 seeds per plant. Total number of flower heads per plant and florets per plant were positively correlated with each other and with the root crown diameter. Root crown diameter is, therefore, a good indicator of potential fecundity in meadow salsify. Greater seed production by larger plants may compensate, at least in part, for the high juvenile mortality and longer generation time in this species. The results suggest that prolific seed production and long vegetative survival are important strategies in the maintenance of meadow salsify populations.


Author(s):  
Irina V. Bogdashina

The article reveals the measures undertaken by the Soviet state during the “thaw” in the fi eld of reproductive behaviour, the protection of motherhood and childhood. Compilations, manuals and magazines intended for women were the most important regulators of behaviour, determining acceptable norms and rules. Materials from sources of personal origin and oral history make it possible to clearly demonstrate the real feelings of women. The study of women’s everyday and daily life in the aspect related to pregnancy planning, bearing and raising children will allow us to compare the real situation and the course of implementation of tasks in the fi eld of maternal and child health. The demographic surge in the conditions of the economy reviving after the war, the lack of preschool institutions, as well as the low material wealth of most families, forced women to adapt to the situation. In the conditions of combining the roles of mother, wife and female worker, women entrusted themselves with almost overwork, which affected the health and well-being of the family. The procedure for legalising abortion gave women not only the right to decide the issue of motherhood themselves, but also made open the already necessary, but harmful to health, habitual way of birth control. Maternal care in diffi cult material and housing conditions became the concern of women and the older generation, who helped young women to combine the role of a working mother, which the country’s leadership confi dently assigned to women.


Author(s):  
Derek Burton ◽  
Margaret Burton

Interspecific fish reproductive patterns, outputs and life cycles display the greatest variability within the vertebrates. Early stages of oogenesis can be repeated in adult fish, contrasting with mammals; the pre-set sequence of cell divisions in gametogenesis is otherwise similar and is described in detail. Most fish deposit much yolk (vitellogenesis) in developing eggs. Migrations, beach-spawning and mouth-brooding are some of the interesting variations. Fertilization is predominantly external but is internal in some groups such as chondrichthyans. The omission of annual reproduction is well established in some freshwater species and the idea that this may also be the case for marine teleosts is gaining acceptance. This should be taken into account for intensively fished species. The possible roles of external cues, hormones, pheromones and neural factors acting as ‘switches’ and coordinators in gametogenesis and reproductive behaviour are discussed.


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