Seasonal growth, reproduction and spore shedding inPterocladia heteroplatos

Author(s):  
N Kaliaperumal ◽  
M Umamaheswara Rao
Author(s):  
R.J.M. Hay ◽  
D.L. Ryan

In a series of trials at Grasslands Gore, over 10 years, the late-flowering tetraploid red clover 'Grassland Pawera' was more productive and persistent than other red clover cultivars. The strong summer growth of Pawera meets the need for heavy-weight lamb feed and high quality forage for conservation in intensive sheep farming systems in Southland. Lenient. infrequent defoliation is necessary to maximise DM production and persistence of Pawera. The most compatible of the grasses evaluated was 'Grasslands Roa' tall fescue. However, 'Grasslands Nui' ryegrass will still be the major grass sown with Pawera owing to its widespread acceptance. In ryegrass mixtures, sowing rates of 5-7 kg/ha of red clover were needed to optimise establishment and subsequent yield. Evidence of oestrogenic activity of Pewera to sheep prompted Grasslands Division to select within Pawera for a low formononetin cultivar. Keywords: red clover, Pawera. Hamua, Turoa. G21. G22, G27. oestrogenic activity, Nui ryegrass, Roa tall fescue, Maru phalaris. Southland, sheep grazing, frequency, intensity, quality. seasonal growth


2020 ◽  
Vol 61 ◽  
pp. 69-76
Author(s):  
A. E. Dedova

This paper presents the results of two years of research (2018-2019) of the most important phonological phases of seasonal growth and development, biometric parameters, productivity and economic efficiency of new varieties of Chinese plum (P. salicina Lindl.) grown in the foothill zone of the North Caucasus in the Krymsk district of Krasnodar territory on a plot of the Krymsk experimental breeding station – branch of VIR. As a result of research, the varieties Angeleno, Black Star, Byron Gold, Black Amber, Larry Ann and Sun Gold were recommended for cultivation using intensive technologies.


1994 ◽  
Vol 6 (5-6) ◽  
pp. 447-454 ◽  
Author(s):  
Israel Levy ◽  
Michael Friedlander

Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 187
Author(s):  
Rolf Vieten ◽  
Francisco Hernandez

Speleothems are one of the few archives which allow us to reconstruct the terrestrial paleoclimate and help us to understand the important climate dynamics in inhabited regions of our planet. Their time of growth can be precisely dated by radiometric techniques, but unfortunately seasonal radiometric dating resolution is so far not feasible. Numerous cave environmental monitoring studies show evidence for significant seasonal variations in parameters influencing carbonate deposition (calcium-ion concentration, cave air pCO2, drip rate and temperature). Variations in speleothem deposition rates need to be known in order to correctly decipher the climate signal stored in the speleothem archive. StalGrowth is the first software to quantify growth rates based on cave monitoring results, detect growth seasonality and estimate the seasonal growth bias. It quickly plots the predicted speleothem growth rate together with the influencing cave environmental parameters to identify which parameter(s) cause changes in speleothem growth rate, and it can also identify periods of no growth. This new program has been applied to multiannual cave monitoring studies in Austria, Gibraltar, Puerto Rico and Texas, and it has identified two cases of seasonal varying speleothem growth.


1964 ◽  
Vol 42 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Austina V. Kennedy ◽  
Helen I. Battle

Cyclic changes in the gonad of Crassostrea virginica (Gmelin), a dioecious, oviparous lamellibranch, are described as they occurred toward the most northerly limit of the range, Malpeque Bay, P.E.I., Canada, during 1961 and 1962. The gonad, composed of right and left gonadal lobes lying immediately beneath the mantle, consists of extensively branched follicles comprising the outer margin of the visceral mass. The follicles open into peripherally located ducts which lead into paired gonoducts terminating in the suprabranchial chamber. During the fall and winter the germinal epithelium is in an indifferent or inactive state. The sex for the current season is distinguishable when proliferation commences in May. Maximum gonadal development occurs in late June or early July as determined by comparison of gonadal width to body width in mid-transverse sections. Primary oocytes are initially distinguishable from oogonia by the presence of a distinct nucleolus, and later by an amphinucleolus consisting of a plasmosome and a karyosome. Seasonal growth of the primary oocyte was followed by a planimetry method using measurements of total area and nuclear area from prepared sections. The spindle for the first meiotic division is established immediately on rupture of the oocyte from the follicular wall. Spermatogenesis and spermiogenesis are completed within the follicle. Following spawning, amoebocytes infiltrate the follicles and interfollicular connective tissue to phagocytize unspawned gametes. By late October the follicles of both male and female consist of a low germinal epithelium and a few unresorbed gametes, and remain inactive until proliferation the following spring.


1967 ◽  
Vol 45 (9) ◽  
pp. 1643-1651 ◽  
Author(s):  
J. Johanna Clausen ◽  
T. T. Kozlowski

Tamarack (Larix laricina (DuRoi) K. Koch) produces long shoots which bear two kinds of needles. Early needles are present in the bud and elongate rapidly after budbreak. Late needles, few of which are present in the bud, elongate later than early needles. Short shoots bear early needles only, and stem length seldom exceeds 1 mm. Seasonal changes in length and weight of needles and stems of both shoot types were measured. In long shoots, 75% of stem elongation, more than 70% of stem weight increment, and 65–70% of late needle elongation occurred after early needles were full-sized. Stem and late needle elongation ceased simultaneously, after which time needle weight decreased and stem weight increased. Early needles probably drew on food reserves while developing, and then themselves contributed to stem and late needle elongation. Final stem weight increase probably used photosynthate from both late and early needles of the current year.Shading of current and last year's needles showed that shoots in which photosynthesis was interrupted in this way produced shorter, lighter-weight stems than did control shoots.


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