scholarly journals Short‐term decline of Castanopsis fargesii adult trees promotes conspecific seedling regeneration: The complete process from seed production to seedling establishment

2020 ◽  
Vol 10 (19) ◽  
pp. 10657-10671
Author(s):  
Li Huang ◽  
Lihua Zhou ◽  
Jingmei Wang ◽  
Cheng Jin ◽  
Siwei Hu ◽  
...  
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Short Term ◽  
Seedling Regeneration ◽  
Castanopsis Fargesii ◽  
Adult Trees ◽  
Complete Process

scholarly journals Some basic concepts of pasture seed mixtures for New Zealand farms

1991 ◽  
pp. 37-40
Author(s):  
J.F.L. Charlton
Keyword(s):  
New Species ◽  
New Zealand ◽  
Seed Production ◽  
Seedling Establishment ◽  
Early Years ◽  
Seeding Rate ◽  
Sowing Time ◽  
Potential Problems ◽  
Basic Concepts ◽  
Species Mixtures

Seeds mixtures for New Zealand pastures developed from British practices with sowing of multi-species seeds mixtures during early years of settlement. Breeding and seed production of ryegrasses and clovers in the 1930s led to use of simple mixtures, still the most commonly used. Since the mid 197Os, new species have been released, and are now becoming more popular. Advantages and some potential problems of species mixtures are outlined, and simple concepts of compiling seeds mixtures are explained, with particular reference to seeding rate and sowing time. Keywords species, seeds mixtures, pasture renewal, sowing rates, seedling establishment, competition

scholarly journals Flowering, Fecundity, Seed Germination, and Seed Viability of Viburnum opulus L. Cultivars

2009 ◽  
Vol 27 (1) ◽  
pp. 31-36
Author(s):  
Janine R. Conklin ◽  
James C. Sellmer
Keyword(s):  
Seed Germination ◽  
Seed Production ◽  
Seed Viability ◽  
Biological Traits ◽  
Limited Information ◽  
Viable Seed ◽  
Invasive Potential ◽  
Short Term ◽  
Viburnum Opulus ◽  
Tetrazolium Test

Abstract Mature specimens of Viburnum opulus and cultivars ‘Leonard's Dwarf’ and ‘Roseum’ were assessed over 2 years for flower and seed production, seed germination, and seed viability as determined by a tetrazolium test to understand their invasive potential. ‘Aureum’, ‘Compactum’, ‘Losely's Compact’, ‘Nanum’, and ‘Xanthocarpum’ were also tested for germination and viability of seeds. Cultivars differed in flower and seed production, seed germination, and seed viability. ‘Roseum’ prolifically produced highly viable seed that germinated at moderate rates under greenhouse conditions (8,354, 100%, and 73%, respectively). Viburnum opulus and ‘Leonard's Dwarf’ produced fewer viable seed which showed moderate to low germination rates (609, 100%, and 53%; 712, 100%, and 5%, respectively). ‘Aureum’ and ‘Xanthocarpum’ seeds germinated at moderate rates (55 and 25%, respectively) and were highly viable (100%). ‘Compactum’, ‘Losely's Compact’, and ‘Nanum’ germinated at low rates or failed to germinate (0, 0, and 5%, respectively), yet seeds were moderately viable (37, 65, and 55%, respectively). Seeds of all cultivars germinated at low rates or failed to germinate at both outdoor sites (0 to 5%) which suggests these plants may be weakly invasive. Short-term studies on biological traits such as these provide only limited information to assess the invasive potential of cultivars.

Long-Term Development of Regeneration Under Longleaf Pine Seedtree and Shelterwood Stands

1993 ◽  
Vol 17 (1) ◽  
pp. 10-15 ◽  
Author(s):  
William D. Boyer
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Stand Density ◽  
Distribution Characteristic ◽  
Volume Increment ◽  
Potential Impact

Abstract Well-stocked mature longleaf pine (Pinus palustris Mill.) stands were cut to five residual basal areas in 1957, namely 9, 18, 27, 36, and 45 ft² per ac, to observe the effect of stand density on seed production and seedling establishment. Seedlings, mainly from the 1955 or 1961seed crops, were established in treated stands. All pines on net 0.9 ac plots were remeasured in 1991 to determine the effect of residual pine density on development of the regeneration. Even the lightest residual overstory converted the structure of 29- to 35- yr-old ingrowth into the reverse-Jdiameter class distribution characteristic of uneven-aged stands. Four or six residual trees, now comprising 7 to 10 ft² basal area (ba)/ac, reduced ingrowth basal area to about half that of same-aged stands released from overstory competition. Merchantable volume of ingrowth under theselow residual densities averaged 40% of that in released stands. Mean annual per ac volume increment of ingrowth averaged 21 to 22 ft³ under the 9 ft² density but did not exceed 7 ft³ under any residual density above this. The potential impact of significant growth reductionsshould be taken into account when considering uneven-aged management methods for longleaf pine. South. J. Appl. For. 17(1):10-15.

Effect of companion perennial grasses and lucerne on seed yield and regeneration of subterranean clover in two wheatbelt environments

2001 ◽  
Vol 52 (10) ◽  
pp. 973 ◽  
Author(s):  
B. S. Dear ◽  
J. M. Virgona ◽  
G. A. Sandral ◽  
A. D. Swan ◽  
B. A. Orchard
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Bank ◽  
Seed Set ◽  
Subterranean Clover ◽  
Seedling Regeneration ◽  
Early Autumn ◽  
Background Population ◽  
Seed Reserves ◽  
Clover Seed

Seed production of subterranean clover (Trifolium subterraneum L.) in mixtures with lovegrass (Eragrostis curvula (Schrader) Nees cv. Consol), cocksfoot (Dactylis glomerata L. cv. Currie), phalaris (Phalaris aquatica L. cv. Sirolan), danthonia (Austrodanthonia richardsonii (Cashm.) H.P. Linder, cv. Taranna), and lucerne (Medicago sativa L. cv. Aquarius) was compared with pure and degraded (invaded by annual volunteers) annual subterranean clover pasture at 2 sites (Junee and Kamarah) in the southern wheatbelt of New South Wales. Seed yields, clover seedlings in winter, and the change in the proportion of 3 subterranean clover cultivars (Dalkeith, Seaton Park, Goulburn) when grown with and without perennials were assessed. The effect of thinning the perennials to 10 plants/m2 on clover seed set was examined at the drier site. Seed production of subterranean clover in the mixtures was depressed by up to 50% compared with the pure and degraded annual swards. Initial clover seed poduction in the mixtures was at least 60 kg/ha even in the drought year at the wetter site (Junee), and >85 kg/ha at Kamarah, the drier site (seedling establishment at Kamarah failed in the drought year). Clover seed reserves in the following 2 years progressively increased to >300 kg/ha in the perennial swards at Junee but were <100 kg/ha by the end of the third year at Kamarah. In comparison, seed reserves in the pure clover and degraded annual swards were >650 kg/ha at Junee and >350 kg/ha at Kamarah. Reducing perennial density to 10 plants/m2 at the drier site increased clover seed yield about 3-fold in the first year compared with unthinned perennial swards. The increased seed yield was due to increased numbers of burrs set and increased seeds per burr and, in all perennial pasture treatments except lucerne, increased seed size. Clover seedling regeneration in 3rd and 4th year after sowing was substantially lower in the perennial-based mixtures than annual plots, with a significant (P < 0.05) positive correlation at both sites between clover seedling regeneration and seed bank size (1996, r2 = 0.46–0.64; 1997, r2 = 0.64–0.85). Following false breaks in early autumn, clover seedling populations were substantially higher in the pure and degraded clover treatments than in most perennial treatments. The proportion of the 3 cultivars present in the seed bank at the end of the pasture phase differed between sites but the sward type only influenced the proportion at the drier site. At the medium rainfall site, the later maturing cultivar Goulburn constituted 27–54% of the seed bank and the early flowering Dalkeith 25–46%, with unsown cultivars being insignificant ( <1%). At the low rainfall site, Dalkeith was the major component (33–52%) of the seed bank but the background population of unsown cultivars constituted 11–48%, the lowest proportion being in swards without a perennial component. The proportion of Goulburn was highest (23%) in the pure sward and lowest (10%) in lucerne and phalaris. It was concluded that subterranean clover could form relatively stable mixtures with perennials in medium rainfall environments, with clover populations increasing with time. In lower rainfall environments, clover seedling populations in perennial swards may be low due to reduced seed set and decreased seedling survival following early autumn rains. In these environments earlier maturing, hard-seeded cultivars are more likely to persist in mixtures and there is more potential for unsown cultivars to constitute a greater proportion of the sward. Decreasing perennial density offers scope for improving clover seed set and survival in these environments.

scholarly journals Effect of Nodal Position of Fruits on Seed Quality of Okra (Abelmoschus esculentus L. Moench)

2020 ◽  
pp. 50-54
Author(s):  
Sunil Kumar ◽  
Satbir Singh Jakhar ◽  
Anil Kumar Malik ◽  
Sangeet Kumar
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Seed Quality ◽  
Dry Weight ◽  
Field Studies ◽  
Abelmoschus Esculentus ◽  
Laboratory Studies ◽  
Seedling Length ◽  
Nodal Position

The present study was carried out in the field and laboratory of the Department of Seed Science and Technology, CCS Haryana Agricultural University, Hisar, Haryana during 2018-2019 to know the effect of nodal position of fruits on seed quality of okra. The parameters recorded during laboratory studies were i.e. germination, seedling length, seedling dry weight, vigour indices-1 & 2 and field studies were i.e. field emergence index, seedling establishment. The results indicated that the best nodal position of fruits for quality seed production was middle nodes (6th to 10th) as compared to lower nodes (1st to 5th) and upper nodes (11th to 15th) and the control.

scholarly journals Short-Term Response of Young Mandarin Trees to Desalinated Seawater Irrigation

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 159 ◽  
Author(s):  
Jose F. Maestre-Valero ◽  
Victoriano Martínez-Alvarez ◽  
Francisco J. Jódar-Conesa ◽  
Jose A. Acosta ◽  
Bernardo Martin-Gorriz ◽  
...  
Keyword(s):  
Water Resources ◽  
Fruit Quality ◽  
Crop Productivity ◽  
Fruit Production ◽  
Economic Effects ◽  
Stem Water Potential ◽  
Short Term ◽  
Gas Exchange Parameters ◽  
Adult Trees

Water deficit and increasing pressure on water resources in semi-arid regions has led to the spread of irrigation with non-conventional water resources, such as desalinated seawater (DSW). The few existent studies to date, mainly carried out in Israel and Spain, have shown that suitable management of irrigation with DSW must be performed to avoid agronomic problems and reductions in crop productivity and fruit quality in the mid-long term. To the best of our knowledge, in the case of citrus, fruit production, and quality, information on the effects of DSW irrigation is not available. In this study, we evaluated the short-term agronomic and economic effects of irrigating a mandarin orchard during two crop cycles (2017–2019) with (i) fresh water (FW), (ii) desalinated seawater (DSW), and (iii) a mix of water composed of 50% FW and 50% DSW. Stem water potential (Ψs < −1 MPa) and gas exchange parameters (net photosynthesis; A > 6.5 µmol/m2/s and stomatal conductance; gs > 65 mmol/m2/s) indicated that trees were well irrigated throughout the experiment. The concentration of Na+ and B3+ in the DSW always exceeded the maximum thresholds for irrigation water proposed in the literature for citrus, and the concentration of Na+ in the leaves exceeded the maximum threshold in summer 2018. Nonetheless, symptoms of toxicity were not observed. Significant differences among treatments were not observed for Ψstem, A, gs, Na+, Cl−, and B3+ in leaves (except in the summer months), yield components, fruit quality, or the economic assessment. The lack of such differences was explained by the large standard deviations caused by the youth of the trees, with figures that on occasion could represent more than 100% of the mean value. These results may justify the agronomic and economic viability of the irrigation of young trees with DSW in the short-term, but further research, considering the effects on adult trees in the long term is still needed.

Andropogon gayanus Kunth invasion in the Cerrado: from seed production to seedling establishment along roadsides

2019 ◽  
Vol 21 (5) ◽  
pp. 1683-1695 ◽  
Author(s):  
Carolina Musso ◽  
Mariana Aragão de Macedo ◽  
Niquele Nunes Almeida ◽  
Danillo de Melo Rodrigues ◽  
Maria Eduarda Moreira Salomon Camargo ◽  
...  
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Andropogon Gayanus

A Postfire Chronosequence of Cone, Follicle and Seed Production in Banksia ornata

1986 ◽  
Vol 34 (4) ◽  
pp. 425 ◽  
Author(s):  
AM Gill ◽  
A Mcmahon
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Quantitative Research ◽  
Weather Conditions ◽  
Fire Intensity ◽  
Stand Age ◽  
Laboratory Conditions ◽  
Western Victoria ◽  
North Western ◽  
Seasonal Weather

The fire-sensitive shrub Banksia ornata relies on seed stored in serotinous 'cones' for its regeneration. Seed release takes place largely as a result of fire but a very small percentage of fruits may open spontaneously. In a chronosequence studied in heaths of the Little Desert of north-western Victoria, we found no seedling establishment in the absence of fire except in the oldest stand, dated at 50+ years since fire. Seed quantity was low in stands 6-7 years old but rose to a peak in the 38-year-old stand. The decline of seed quantity in the 50+ year-old stand was due to dieback and death of bushes. There was no evidence for an increase in the proportion of seeds predated with age of stand. An average of about 70% of the seed was regarded as 'intact' (no sign of damage) and about 80% of these seeds germinated under ideal laboratory conditions. It was estimated that the amount of seed available for regeneration increased with stand age up to 38 years but declined by 50+ years. It was suggested that a period of 16 years without fire could be needed to achieve stand replacement of populations of this species. The age at which full replacement can be achieved will vary, however, according to fire intensity and seasonal weather conditions. Further quantitative research is needed.

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