Phenology and seed production in Chenopodium rubrum, Rumex maritimus, and Rumex palustris as related to photoperiod in river forelands

1992 ◽  
Vol 70 (2) ◽  
pp. 392-400 ◽  
Author(s):  
A. J. M. Van der Sman ◽  
C. W. P. M. Blom ◽  
H. M. Van de Steeg
Keyword(s):  
Life Cycle ◽  
Seed Production ◽  
Population Level ◽  
Flowering Phenology ◽  
Chenopodium Rubrum ◽  
Axillary Shoots ◽  
Critical Photoperiod ◽  
Number Of Leaves ◽  
Rumex Maritimus ◽  
Flooded Areas

Reproductive development in three species from irregularly flooded areas of river forelands was studied in relation to time of emergence. In Chenopodium rubrum, flowering was induced earlier in plants germinated in April–May than in later cohorts. However, the period of vegetative growth diminished and the life cycle was completed in a shorter time in later germinated plants. Seed number was reduced, but seed size as well as reproductive effort per plant increased in later cohorts. Plants of both Rumex species flowered after a certain number of leaves had developed and before a critical photoperiod had passed. In earlier cohorts, the main shoot and several axillary shoots elongated and flowered. Fewer axillary shoots flowered closer to the critical photoperiod, and this resulted in a reduced seed output in later cohorts. The critical photoperiod as well as the time needed for completion of the life cycle was longer in Rumex palustris than in Rumex maritimus. It is argued that in the riparian habitat, plants of both Rumex species are only occasionally able to complete their life cycle in one growing season. Survival of these species on the population level will rely more upon adaptations towards flooding during the established phase than is the case for C. rubrum. Key words: flowering phenology, photoperiod, seed production, Chenopodium rubrum, Rumex maritimus, Rumex palustris.

scholarly journals Life cycle inventory for the production of germinated oil palm seeds at a selected seed production unit in Malaysia

2013 ◽  
Author(s):  
Nik Sasha Khatrina Khairuddin ◽  
B. S. Ismail ◽  
Halimah Muhamad ◽  
Choo Yuen May
Keyword(s):  
Life Cycle ◽  
Seed Production ◽  
Oil Palm ◽  
Life Cycle Inventory ◽  
Production Unit

Upscaling site-scale ecohydraulic models to inform salmonid population-level life cycle modeling and restoration actions - Lessons from the Columbia River Basin

2017 ◽  
Vol 43 (1) ◽  
pp. 21-44 ◽  
Author(s):  
Joseph M. Wheaton ◽  
Nicolaas Bouwes ◽  
Peter Mchugh ◽  
Carl Saunders ◽  
Sara Bangen ◽  
...  
Keyword(s):  
Life Cycle ◽  
River Basin ◽  
Columbia River ◽  
Population Level ◽  
Columbia River Basin

scholarly journals Reproductive diapause in Nysius huttoni White (Heteroptera Lygaeidae)

2002 ◽  
Vol 55 ◽  
pp. 308-311
Author(s):  
X.Z. He ◽  
Q. Wang ◽  
A. Carpenter
Keyword(s):  
Life Cycle ◽  
Immature Stages ◽  
Life Stages ◽  
Reproductive Diapause ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Adult Females ◽  
Critical Photoperiod

The induction of reproductive diapause of Nysius huttoni was studied in the laboratory at 20 1C and 60 10 RH under a series of photoperiod regimes 168 h 1410 h 1212 h and 1014 h lightdark Reproductive diapause was considered to have occurred if females failed to lay eggs for 50 days after emergence The sensitivity of different life stages to diapauseinducing photoperiods varied When newly emerged females whose immature stages had been reared at 168 h were transferred to 1014 h and 1212 h 467 and 793 of them entered reproductive diapause respectively However when fifth instar nymphs were transferred from 168 h to 1014 h and 1212 h 100 of adult females entered reproductive diapause If the entire life cycle was maintained at 1014 h and 1212 h 667 and 400 of females entered reproductive diapause respectively The critical photoperiod for reproductive diapause was estimated to lie between 1311 h and 135105 h

scholarly journals Resource‐related variables drive individual variation in flowering phenology and mediate population‐level flowering responses to climate in an asynchronously reproducing palm

Biotropica ◽  
2020 ◽  
Vol 52 (5) ◽  
pp. 845-856
Author(s):  
Tadeo Ramirez‐Parada ◽  
Domingo Cabrera ◽  
Zoe Diaz‐Martin ◽  
Luke Browne ◽  
Jordan Karubian
Keyword(s):  
Individual Variation ◽  
Population Level ◽  
Flowering Phenology

scholarly journals Influence of Detasseling Methods on Seed Yield of Some Parent Inbred Lines of Turda Maize Hybrids

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 729
Author(s):  
Alexandru Bogdan Ghețe ◽  
Voichița Haș ◽  
Roxana Vidican ◽  
Ana Copândean ◽  
Ovidiu Ranta ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Weather Conditions ◽  
Inbred Lines ◽  
Plant Performance ◽  
Yield Response ◽  
Genetic Purity ◽  
Short Period ◽  
Number Of Leaves ◽  
Hybrid Maize

During the process of maize seed production, in order to ensure the genetic purity of parental forms of hybrid maize, an important work performed is the removal of male inflorescences from plants on mother rows. Hand detasseling has high precision but is labor-intensive. Mechanical detasseling offers the possibility to cover large acreages in a short period of time, but the number of leaves removed has a varying influence on plant performance and seed yield. The aim of this study was to simulate three types of damages on plants similar to those induced through mechanical detasseling and to assess the effects for five inbred lines during the course of three years. Results show that when tassels alone were removed, the average seed yield decreased an average of 4–21%. When two leaves were removed with the tassel, yield decreased an average of 22–31%, while when plants were cut above the main ear, seed yield decreased an average of 31–66%. Environmental conditions influenced seed yield, especially high temperatures during flowering. Yield response to tassel and leaves removal varied between the inbred lines. Genotype controls maize ear and kernel characters, while environmental factors exercise a strong influence on seed yield, due to the succession of years with contrasting weather conditions in a key phenophase. Within the trend of full mechanization in agriculture, identification of inbred lines that cope better with plant damage can assist in optimizing seed production.

scholarly journals Life Cycle Assessment of Oyster Farming in the Po Delta, Northern Italy

Resources ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 170 ◽  
Author(s):  
Tamburini ◽  
Fano ◽  
Castaldelli ◽  
Turolla
Keyword(s):  
Life Cycle Assessment ◽  
Supply Chain ◽  
Life Cycle ◽  
Seed Production ◽  
Northern Italy ◽  
Short Supply ◽  
Current Scenario ◽  
Po Delta ◽  
The Impact ◽  
Aquaculture Production

Oysters represent an important portion of the world’s total aquaculture production. In recent years, in Italy, oyster farming has progressively increased its role in the economic growth of the aquaculture sector and still has great potential for growth. As in any other production, oyster farming generates environmental impacts over an oyster’s life cycle, due to material, energy, fuel, and water use. The aim of this work was to carry out a cradle-to-gate life cycle assessment (LCA) of 1 kg of fresh oysters of commercial size produced in the Po delta area, northern Italy. Two scenarios were considered. The current scenario provides for oyster seed purchasing from France and transport to Italy, whereas the alternative scenario includes in situ seed production in order to realize a complete local and traceable supply chain. Eco-indicator® 99-H and ReCiPe® midpoint (H) v.1.12 were used to perform the impact assessments. The overall impacts of the two scenarios were very similar and indicated that the main hotspots were the fattening and prefattening phases of farming, which were common in both scenarios. Focusing the analysis on the first stages, transport from France had a greater impact than did local seed production, emphasizing the importance of a short supply chain in aquaculture production.

Delayed selfing and low levels of inbreeding depression in Hibiscus trionum (Malvaceae)

2003 ◽  
Vol 51 (3) ◽  
pp. 275 ◽  
Author(s):  
Mike Ramsey ◽  
Leahwyn Seed ◽  
Glenda Vaughton
Keyword(s):  
Life Cycle ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Flower Production ◽  
Delayed Selfing ◽  
Life Cycle Stages ◽  
Hibiscus Trionum ◽  
Eastern Australia ◽  
Annual Herb ◽  
Low Levels

We used experimental pollinations to examine the breeding system and inbreeding depression in Hibiscus trionum L., an annual herb of cultivated and disturbed sites in eastern Australia. Seeds were not produced asexually. Flowers were fully self-compatible and autonomously self-pollinating. Autonomous self-pollination was due to a delayed selfing mechanism that gave precedence to cross pollen but ensured that stigmas contacted the anthers at the end of floral life. Using selfed and crossed progeny from 10 maternal plants, we examined the magnitude and timing of inbreeding depression over a range of life-cycle stages, including seed production by maternal plants, and seed germination, seedling growth, survival, flowering and seed production by F1 plants. Average cumulative inbreeding depression was 0.15, although there was considerable variation among maternal families (δ = –0.07–0.43). Inbreeding depression was not uniform across all life stages and was most prevalent late in the life cycle, affecting days to flowering and fruiting and flower production. Our results indicate that major lethal alleles have been purged from this population, probably through high levels of recurrent self-fertilisation. The flexibility in plant mating afforded by delayed selfing is likely to contribute to the invasiveness of H. trionum, particularly in annual cropping situations.

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