Flower and seed production as affected by axis category and shoot size in two Patagonian Nothofagus species

Botany ◽  
2012 ◽  
Vol 90 (4) ◽  
pp. 261-272 ◽  
Author(s):  
Cristian D. Torres ◽  
Javier G. Puntieri ◽  
Marina Stecconi

Flower distribution within the tree crown may affect both pollination dynamics and the costs of flowering on tree growth. For Nothofagus obliqua (Mirb.) Oerst. and Nothofagus nervosa (Phil.) Krasser, the production of flowers and viable seeds were compared among axes of contrasting size and category in the tree crown. For annual shoots arising from three axis categories (main branches, secondary branches, and twigs), the numbers of nodes, staminate flowers, pistillate flowers and axillary buds, and seed viability were evaluated. Most flowering shoots produced both staminate and pistillate flowers. The number of flowers of each type was related positively with the number of nodes of the shoot. Longer shoots had proportionally more pistillate flowers than short shoots. The three axis categories produced both flower types in direct proportion to the size of their shoots, but main branches presented more axillary vegetative buds than secondary branches and twigs. For N. obliqua, the percentage of viable seeds was lower in secondary branches than in main branches and twigs, perhaps owing to a lower probability of cross-pollination in secondary branches. The coexistence of vegetative and reproductive functions may cause interference between them. Massive allocation of meristems to flowering reduces meristem availability for growth and, especially, flowering in the following growing season.

2021 ◽  
Vol 845 (1) ◽  
pp. 012026
Author(s):  
V A Sergeeva ◽  
A A Muravyov ◽  
L M Vlasova

Abstract The production experiments were carried out based on the farm “Yaroslav the Wise” of the Starooskol district of the Belgorod region. The article studies the effect of the biological product Biogor KM during the pre-sowing treatment of grain in combination with double spraying of growing plants of spring durum wheat Dar Chernozemya 2. One of the experiments provides for grain processing with the period of “germination-ripening” of its wheat plants reduced by 8 days. The second variant, in addition to processing the grain, had two sprayings carried out during the growing season. The second experiment lasted even less by 12 days in comparison with the control variant. The article establishes the positive influence of the biological product on the formation of the productivity structure of spring durum wheat plants. Grain processing in combination with spraying during the growing season led to the formation of the best productivity structure: plant height was 39% higher, the number of spikelets was 41.8% higher, the number of spikelets was higher by 35.3%, and the grain weight per spike was 39.2%. versus the control variant. The yield in the experiment was in direct proportion to the method of application of the biological product and the conditions of the growing season. The largest increase in yield - 0.40 t / ha or 14.5% was obtained in the variant with grain processing in combination with double spraying of plants during the growing season, the average yield for the studied period was 3.14 t / ha and was maximum, indicators of economic and bioenergy efficiency was also the best.


2010 ◽  
Vol 56 (No. 12) ◽  
pp. 580-583 ◽  
Author(s):  
Z. Martinková ◽  
A. Honěk

After flowering has ceased, dandelion (Taraxacum agg.) capitula close to enable maturation of seeds. In late summer the period of seed maturation lasts for 9 days. The capitula mowed later than 4 days after the start of this period and desiccated at 25°C produce viable seeds. If cut and prostrated on insolated ground inflorescences can experience temperatures exceeding 50°C which may impair seed viability. We determined the effect of desiccation temperature (5, 15, 25, 35, 45 or 55°C) on viability of ripening seeds using inflorescences harvested on September 5, 2008 at Prague-Ruzyne (50°05'N, 14°18'09 E), five days after flowering ceased (about 4 days before seed dispersal). As control, ripe seeds were collected at dispersal on the same day and desiccated at identical temperatures. Desiccated seeds were germinated at constant 17°C. Ripening seeds of maturing capitula only remained germinable if desiccation temperatures were ≤ 35°C (optimum 25°C) and were killed at 45 and 55°C. The viability of ripe seed was not affected by any of the desiccation temperatures. Time of germination of 50% seeds that germinated was significantly shorter in ripe than ripening seeds. Exposure of mowed dandelion inflorescences on insolated ground (solarization) may thus decrease production of viable seeds because of high temperatures experienced during desiccation.  


1972 ◽  
Vol 12 (58) ◽  
pp. 517 ◽  
Author(s):  
RL Harty ◽  
LG Paleg ◽  
D Aspinall

The reduction of 2,3,5-triphenyl tetrazolium chloride (TTC) to a coloured formazan derivative by dehydrogenase enzyme systems in viable seeds has been examined. TTC reduction occurs in dry but not wetmilled tissue and the coloured product could be extracted by any of several organic solvents. This formazan product was estimated spectrophotometrically at 480 nm. The influence of fineness of grinding the tissue, TTC concentration, period of treatment, sample size, vacuum infiltration of the milled tissue with TTC and of extracting solvent were examined and a standard procedure is suggested. Using this procedure, a close correlation between seed viability and TTC reduction was demonstrated. The advantages of this method over the widely used topographical method for estimating seed viability with TTC are discussed.


2002 ◽  
Vol 12 (1) ◽  
pp. 17-29 ◽  
Author(s):  
T. Repo ◽  
D.H. Paine ◽  
A.G. Taylor

A method, electrical impedance spectroscopy (EIS), is introduced to study seed viability non-destructively. Snap bean (Phaseolus vulgaris L.) seeds were studied by EIS to determine the most sensitive EIS parameter(s) and the optimal range of moisture content (MC) for separation of viable and non-viable seeds. Hydrated seeds exhibited two impedance arcs in the complex plane at the frequency range from 60 Hz to 8 MHz, and impedance spectra of viable and non-viable seeds differed. The hydrated seeds were best-modelled by an equivalent electrical circuit with two distributed circuit elements in series with a resistor (Voigt model). Moisture content and seed viability had strong effects on the EIS parameters. The most sensitive EIS parameters for detecting the differences between viable and non-viable seeds were the capacitance log(C2), the resistance R2, the resistance ratio R2/R1 and the apex ratio, which all represent specific features of the impedance spectrum. The highest differentiation in the EIS parameters between the viable and non-viable seeds occurred in partially imbibed seeds between MC of 40 and 45% (fresh weight basis).


1983 ◽  
Vol 63 (3) ◽  
pp. 695-709 ◽  
Author(s):  
S. I. WARWICK ◽  
R. D. SWEET

A summary of biological information is provided on two species of Galinsoga — G. parviflora (small-flowered galinsoga) and G. quadriradiata (hairy galinsoga). Originating in Central America, both species are weeds of disturbed habitats and agricultural areas, occurring in most of the temperate and subtropical regions of the world. In recent years the galinsogas have become troublesome weeds of low-growing vegetable crops in northeastern North America. The two species serve as alternate hosts for many insects, viruses and nematodes which affect crop species. Both species possess several features which predispose them to weediness and contribute to a rapid buildup of populations after an initial infestation. These include lack of seed dormancy, lack of special requirements for germination, rapid seedling development, the ability to flower after a short period of vegetative growth, the production of flowers and fruits throughout the growing season, the production of several generations in a single growing season, self-compatibility and the production of large numbers of viable seeds under a wide range of environmental circumstances.Key words: Galinsoga parviflora, G. quadriradiata, biology


1994 ◽  
Vol 4 (2) ◽  
pp. 123 ◽  
Author(s):  
KW Outcalt

Wiregrass (Aristida stricta Michx.) is a major species in the long leaf pine (Pinus palustris Mill.) sandhills areas of central Florida, providing a major portion of the fuel for the recurring ground fires necessary to maintain the community. Growing season burning promotes flower and seed production. The objective of this study was to assess the seed production potential of wiregrass following prescribed burns from May through August. Four longleaf wiregrass sites were prescribed burned, one each in May, June, July, and August. Information on bunch size, bunch density, seed stalk density, seed density, and seed germination were collected. The four sites differed significantly in the density of wiregrass bunches, average bunch size, wiregrass cover and seed viability. The density of seed stalks was fairly consistent across sites. Viable seed production was lowest on the June burned site and highest on the July burned site. The study shows good quantities of seed are comparatively easy to produce with growing season bums.


2021 ◽  
Vol XII (2(21)) ◽  
Author(s):  
Natalia Cirlig ◽  
◽  
◽  

Phacelia tanacetifolia Benth., which is a species with high potential as forage and honey plant, served as the subject of a new study. The species is characterized by short growing season, staggered and long flowering period (about 55 days depending on the climatic conditions and the date when it was sown). Under laboratory conditions, the germination capacity of the seeds is 84-92 %. The climatic conditions of the Republic of Moldova allow P. tanacetifolia plants to complete the whole ontogenetic development cycle – they bloom, bear fruit and produce viable seeds.


1999 ◽  
Vol 7 ◽  
pp. 151-156
Author(s):  
D.E. Hume ◽  
M.P. Rolston ◽  
D.B. Baird ◽  
W.J. Archie ◽  
M.R. Marsh

Emergence of volunteer perennial ryegrass (Lolium perenne L.) from seed buried in soil may contribute to the ingress of ryegrass in newly sown pastures. To investigate this, ryegrass seed infected with fungal endophyte (Neotyphodium lolii) was buried in nylon bags under pasture at two depths and at two sites (Palmerston North, Lincoln) in early/mid-autumn 1998. Seed bags were removed from the soil at intervals over the course of one year to determine seed viability and presence of endophyte in seedlings. Viability of seed declined rapidly to be 10% 3 months after burial. Further decline in viability was less, so that 12 months after burial 4% of seeds were still viable. Endophyte viability also declined, from 58% infection of seedlings at the time of burial to 21% at 12 months. This was at a slower rate than the decline in seed viability and from what might have been predicted from seed storage experiments. Viability of seed buried at 10 cm was greater than that buried at 3 cm (e.g., means, 10% and 1% after 6 months, respectively). This has implications for cultivation practices before pasture establishment. Seed buried at Lincoln maintained higher viability than seed buried at Palmerston North (e.g., means, 6% and 4% after 6 months, respectively), which was associated with drier soil conditions at Lincoln. Survival of buried seed may therefore be of greater importance in summer-dry east coast regions, compared with moist west coast environments or in wet years. The significance of buried ryegrass seed will depend on the numbers involved, but after 12 months there were still viable seeds left in the soil and some of these were infected with endophyte. This is important for pastures sown with ryegrass that is free of endophyte or infected with a selected endophyte, and for slower establishing grass species such as tall fescue. Keywords: endophyte, endophyte survival, Lolium perenne, Neotyphodium lolii, perennial ryegrass, seed burial, seed survival


2019 ◽  
Vol 4 (1) ◽  
pp. 23-30
Author(s):  
Taufiq Hidayat RS ◽  
Mayasari Yamin

This study was aimed to determine the viability rate of rosella seed, to obtain the best result of seed testing for enhancing rosella seed viability, to find the best seed invigoration method for enhancing rosella seed viability, to obtain staining pattern through tetrazolium test of rosella seed, and to determine viability and vigor of rosella seed to be further used as estimation indicator for rosella plant growth in the field. The study was conducted in the Seed Laboratory, Indonesian Sweetener and Fiber Crops Research Institute (ISFCRI), Malang, East Java during July - August 2018. The material used included accessions of rosella seed (Hibiscus sabdariffa L.) ACC. 1148 from the year 2015 and collection of ISFCRI, 100 ml of Tetrazolium solution (40 ml KH2PO4, 60 ml Na2HPO4 and 1 gr of Tetrazolium powder). This research applied Completely Randomized Design (CRD) consisted of seed treatments of control (no immersion/0 hour), immersion for 5 hours, immersion for 10 hours, and scarification, each with 4 replications. Result of this study showed that the use of tetrazolium salt was found to be better in enhancing the viability of rosella seeds. Viable seeds was found to have bright red embryonic axis and bright red cotyledon. Testing using paper media on several seed invigoration treatments resulted in significantly different effect on parameters of vigor index, germination capacity, and dry weight of normal seedling. The best parameter of germination capacity and dry weight of normal seedling was obtained by treatment immersed in water at temperature of 27°C for 10 hours


2022 ◽  
Vol 28 (1) ◽  
pp. 85-91
Author(s):  
Vespasiano Borges de Paiva Neto ◽  
Mateus de Aguiar Torrezan ◽  
Manoela Aparecida Vieira da Silva ◽  
Daly Roxana Castro Padilha ◽  
Jerônimo Constantino Borel ◽  
...  

Abstract Cycnoches haagii Barb. Rodr. is an epiphytic orchid very targeted by collectors, but no reference was found in the literature about its reproductive biology. Thus, the purpose of this study was to obtain initial information regarding pollination types and its influence on seed viability of this native orchid of the Brazilian Cerrado, in order to enable future propagation and preservation programs. Pollination among flowers of the same plant (geitonogamy) or different plants (xenogamy) were carried out. Seeds extracted from the capsules were sown in B&G medium, with full and half strength. Seeds from geitonogamic resulted in 25% of albino protocorms and consequently in albino seedlings. This phenomenon did not occur in seedlings derived from xenogamic pollination. Pigment analysis showed that even the albino seedlings presented chlorophylls and carotenoids, however, in significantly minor concentrations, 16% and 37% respectively, in relation to green seedlings. Geitonogamic and xenogamic pollinations resulted in C. haagii viable seeds with high germination percentage (90%) under in vitro conditions. The germination of seeds from xenogamic pollination resulted in chlorophyll or normal seedlings only, and can be recommended at conservation programs. On the other hand, although geitonogamic pollination should be avoided at conservation programs of this orchid species as it leads to albino seedlings, it showed a very interesting system to obtain seedlings with this phenotype, an interesting plant material to future investigation.


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