scholarly journals Density-dependent effect of allelopathy on germination and seedling emergence in two Ipomoea species

2019 ◽  
Vol 92 (1) ◽  
Author(s):  
Zoila Mercedes Aguilar-Franco ◽  
Alejandro Flores-Palacios ◽  
Alejandro Flores-Morales ◽  
Irene Perea-Arango ◽  
José de Jesús Arellano-García ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Single Species ◽  
Allelopathic Effect ◽  
Plant Interactions ◽  
Species Trials ◽  
Germination Experiments ◽  
Action Modes ◽  
First Time ◽  
Seed Extracts

Abstract Background Density in inter and intraspecific plant-plant interactions affects the action modes of allelopathy (autotoxicity, negative and positive allelopathy). Some seeds exude compounds that inhibit the germination of others. Ipomoea murucoides and I. pauciflora are sympatric tree species that form patches at the local scale where one or the other dominates, possibly due to allelopathy in the seeds. The objective of this study was to determine the possible density-dependence of the allelopathic effect among seeds of these species through the measure of seed germination and seedling emergence. Methods In both species, allelopathy was measured as: a) germination in mixed sowing of both species at different proportions, b) germination in single-species trials at different densities after adding seed extracts of both species, and c) seedling emergence in seed mixtures of both species sown at different proportions beneath canopies of the two Ipomoea species. Results Seed germination of I. murucoides was increased by the presence of I. pauciflora and diminished at higher densities of its own seeds; however, seed germination of I. pauciflora was not affected by the presence of I. murucoides seeds. The addition of extracts (either from conspecifics or congeneric) diminished the germination of both species and at higher seed densities the germination was lower. Seedling emergence did not depend on the species under which the seeds were sown nor on the density of the seeds. Conclusions The germination experiments evidenced positive allelopathy and/or autotoxicity, while there was no evidence of allelopathic effects in seedling emergence. The allelopathic activity is reported in the seeds of these species for the first time.

Seed afterripening and germination photoinhibition in the genusCrocus(Iridaceae)

2015 ◽  
Vol 25 (3) ◽  
pp. 306-320 ◽  
Author(s):  
Evangelia Skourti ◽  
Costas A. Thanos
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Low Temperatures ◽  
Temperate Climate ◽  
Optimal Temperature ◽  
Continuous Darkness ◽  
Dry Storage ◽  
The Mediterranean ◽  
Germination Experiments ◽  
First Time

AbstractMediterranean characteristics are attributed to the genusCrocus, which is inadequately studied in terms of seed germination. An afterripening requirement is very common in environments with warm and dry periods, and photoinhibition has been detected in many angiosperms inhabiting dry and open areas. The effects of afterripening and light on seed germination were investigated for the first time in 23 native GreekCrocustaxa, collected from various localities with either a Mediterranean or a temperate climate. Germination experiments were conducted in continuous darkness and in light at the optimal temperature for each taxon, with both freshly collected and afterripened seeds; warm stratification (20°C, darkness) was also examined in 22 taxa. A number of selected taxa were additionally investigated with respect to afterripening outdoors, afterripening and warm stratification at higher temperatures (35 and 25°C, respectively), stratification at 20/10°C, dry storage at low temperatures, response to gibberellic acid and phenology of embryo growth. It was postulated that an afterripening requirement is a characteristic of the genusCrocus, and we found that it can be fulfilled in nature during the Mediterranean dry summer. Also, for the vast majority of the taxa, warm stratification and stratification at 20/10°C can both meet the afterripening requirement. Embryos of the taxa studied are underdeveloped and have to grow prior to germination. Intrageneric differences of seed germination were observed only towards light, with photoinhibition being predominant in taxa from drier environments.

Allelopathic effect of cumin (Cuminum cyminum L.) on seed germination of three weeds

Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
A Soleymanifard ◽  
R Naseri ◽  
A Mirzaei ◽  
H Naserirad
Keyword(s):  
Seed Germination ◽  
Allelopathic Effect ◽  
Cuminum Cyminum

Allelopathic effect of potato on Orabanche aegyptiaca Pers seed germination

2013 ◽  
Vol 21 (3) ◽  
pp. 333
Author(s):  
Zhong WANG ◽  
YongQing MA ◽  
JinNan JIA ◽  
ShuQi DONG ◽  
XiaoXin YE
Keyword(s):  
Seed Germination ◽  
Allelopathic Effect

scholarly journals Allelopathic Effect of Serphidium kaschgaricum (Krasch.) Poljak. Volatiles on Selected Species

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 495
Author(s):  
Shixing Zhou ◽  
Toshmatov Zokir ◽  
Yu Mei ◽  
Lijing Lei ◽  
Kai Shi ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Volatile Oil ◽  
Amaranthus Retroflexus ◽  
Allelopathic Effect ◽  
Chemical Profile ◽  
Volatile Oils ◽  
Phytotoxic Activity ◽  
Volatile Organic ◽  
First Time ◽  
Stem Leaf

The chemical profile and allelopathic effect of the volatile organic compounds (VOCs) produced by a dominant shrub Serphidium kaschgaricum (Krasch.) Poljak. growing in northwestern China was investigated for the first time. Serphidium kaschgaricu was found to release volatile compounds into the surroundings to affect other plants’ growth, with its VOCs suppressing root elongation of Amaranthus retroflexus L. and Poa annua L. by 65.47% and 60.37% at 10 g/1.5 L treatment, respectively. Meanwhile, volatile oils produced by stems, leaves, flowers and flowering shoots exhibited phytotoxic activity against A. retroflexus and P. annua. At 0.5 mg/mL, stem, leaf and flower oils significantly reduced seedling growth of the receiver plants, and 1.5 mg/mL oils nearly completely prohibited seed germination of both species. GC/MS analysis revealed that among the total 37 identified compounds in the oils, 19 of them were common, with eucalyptol (43.00%, 36.66%, 19.52%, and 38.68% in stem, leaf, flower and flowering shoot oils, respectively) and camphor (21.55%, 24.91%, 21.64%, and 23.35%, respectively) consistently being the dominant constituents in all oils. Eucalyptol, camphor and their mixture exhibited much weaker phytotoxicity compared with the volatile oils, implying that less abundant compounds in the volatile oil might contribute significantly to the oils’ activity. Our results suggested that S. kaschgaricum was capable of synthesizing and releasing allelopathic volatile compounds into the surroundings to affect neighboring plants’ growth, which might improve its competitiveness thus facilitate the establishment of dominance.

scholarly journals Remarkable Species Diversity of the Leafhopper Genus Xestocephalus (Hemiptera: Cicadellidae: Aphrodinae) in Thailand

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 514
Author(s):  
Zonglei Liang ◽  
Christopher H. Dietrich ◽  
Wu Dai
Keyword(s):  
New Species ◽  
Species Diversity ◽  
Single Species ◽  
Comparative Morphology ◽  
Malaise Trap ◽  
Field Sampling ◽  
Tropical Regions ◽  
Trap Field ◽  
The World ◽  
First Time

Xestocephalus Van Duzee is among the most common and widespread genera of Cicadellidae in the temperate and tropical regions of the world. In the present study, 205 specimens of the genus Xestocephalus were collected in Thailand, whereas only a single species of the genus was recorded previously using Malaise trap field sampling, studied by comparative morphology. Seventeen species were recognized, including twelve new species: X. binarius sp. nov., X. chrysanthemum sp. nov., X. cowboyocreus sp. nov., X. densprint sp. nov., X. dimiprocessus sp. nov., X. exproiecturus sp. nov., X. gracilus sp. nov., X. limpidissimus sp. nov., X. malleus sp. nov., X. nonattribus sp. nov., X. recipinams sp. nov., and X. tenusis Liang sp. nov. Four species were recorded in Thailand for the first time: Xestocephalus abyssinicus Heller and Linnavuori, Xestocephalus asper Linnavuori, Xestocephalus ishidae Matsumura, and Xestocephalus toroensis Matsumura. Detailed morphological descriptions of all 17 species are given; photographs of external habitus and male genitalia of the species from Thailand are provided. A checklist of species of the genus is also given, and a key to all Thailand Xestocephalus species is also provided.

scholarly journals A Synopsis of Orthotrichum s. lato (Bryophyta, Orthotrichaceae) in China, with Distribution Maps and a Key to Determination

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 499
Author(s):  
Vítězslav Plášek ◽  
Zuzana Komínková ◽  
Ryszard Ochyra ◽  
Lucie Fialová ◽  
Shuiliang Guo ◽  
...  
Keyword(s):  
Single Species ◽  
Herbarium Specimens ◽  
Distribution Maps ◽  
First Time

A total of 46 species and two varieties of the traditionally interpreted genus Orthotrichum are currently known to occur in China. They represent five genera, including Orthotrichum (29 species), Lewinskya (14 species and two varieties), and Nyholmiella and Leratia that are represented by a single species each. The fifth genus Florschuetziella, also consisting of only one species, F. scaberrima, is an entirely neglected representative of the China’s moss flora. A list of all accepted taxa is presented and for each taxon all literature records and herbarium specimens are enumerated for provinces in which they have been recorded, and their distribution is mapped. A key to determination of Chinese orthotrichalean mosses is presented. A chronological list of 63 species and varieties and two designations, O. catagonioides and O. microsporum which have never been validly published, reported from China in the years 1892–2020 is presented. Four species, Orthotrichum brasii, O. hooglandii, O. elegans and O. gymnostomum are excluded from the bryoflora of China and Lewinskya affinis var. bohemica and Orthotrichum schimperi are recorded for the first time from this country. Phytogeography of the Chinese taxa of the orthotrichalean mosses is considered and they are grouped into eight phytogeographical elements and five sub-elements.

scholarly journals Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Yonghuan Yue ◽  
Guili Jin ◽  
Weihua Lu ◽  
Ke Gong ◽  
Wanqiang Han ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Germination Percentage ◽  
Western China ◽  
Burial Depth ◽  
Achnatherum Inebrians ◽  
Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

scholarly journals Seed longevity of maize conserved under germplasm bank conditions for up to 60 years

2021 ◽  
Author(s):  
Filippo Guzzon ◽  
Maraeva Gianella ◽  
Jose Alejandro Velazquez Juarez ◽  
Cesar Sanchez Cano ◽  
Denise E Costich
Keyword(s):  
Seed Germination ◽  
Plant Genetic Resources ◽  
Seed Viability ◽  
Storage Conditions ◽  
Seed Longevity ◽  
Germplasm Bank ◽  
Significant Difference ◽  
Different Temperatures ◽  
Germination Experiments

Abstract Background and Aims The long-term conservation of seeds of plant genetic resources is of key importance for food security and preservation of agrobiodiversity. Nevertheless, there is scarce information available about seed longevity of many crops under germplasm bank conditions. Methods Through germination experiments as well as the analysis of historical monitoring data, we studied the decline in viability manifested by 1000 maize (Zea mays subsp. mays) seed accessions conserved for an average of 48 years at the CIMMYT germplasm bank, the largest maize seedbank in the world, under two cold storage conditions: an active (–3 °C; intended for seed distribution) and a base conservation chamber (–15 °C; for long-term conservation). Key Results Seed lots stored in the active chamber had a significantly lower and more variable seed germination, averaging 81.4 %, as compared with the seed lots conserved in the base chamber, averaging 92.1 %. The average seed viability detected in this study was higher in comparison with that found in other seed longevity studies on maize conserved under similar conditions. A significant difference was detected in seed germination and longevity estimates (e.g. p85 and p50) among accessions. Correlating seed longevity with seed traits and passport data, grain type showed the strongest correlation, with flint varieties being longer lived than floury and dent types. Conclusions The more rapid loss of seed viability detected in the active chamber suggests that the seed conservation approach, based on the storage of the same seed accessions in two chambers with different temperatures, might be counterproductive for overall long-term conservation and that base conditions should be applied in both. The significant differences detected in seed longevity among accessions underscores that different viability monitoring and regeneration intervals should be applied to groups of accessions showing different longevity profiles.

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