scholarly journals IMPROVEMENT OF SEED GERMINATION BEHAVIOUR IN PHYLLANTHUS AMARUS BY ACID AND MECHANICAL SCARIFICATION PRETREATMENTS

2014 ◽  
Vol 19 ◽  
pp. 1-5
Author(s):  
Meenu Gehlot ◽  
Pawan K. Kasera

Phyllanthus amarus (Bhui-Aanwalaa: Family: Euphorbiaceae) is considered to be the most important medicinal plant of the Indian Thar desert. The present article deals with its seed morphological parameters, seed output, reproductive capacity (RC), germination behavior, seedling growth, root: shoot ratio (R/S ratio), germination value (GV) and vigour index (VI) in fresh and one-year-old seeds under controlled laboratory conditions. Results revealed that 73.33 and 60% germination was observed in fresh and one-year-old seeds as compared to the control (20% in fresh; while 36.67% in one-year-old seeds) after providing mechanical + conc. H2SO4 scarification for 2 and 1 min, respectively. The maximum VI and GV were obtained in mechanical + conc. H2SO4 scarification for 2 min pretreatments in fresh seeds.DOI: http://dx.doi.org/10.3126/eco.v19i0.9848EcoprintAn International Journal of EcologyVol. 19, 2012Page: 1-5Uploaded date: 2/14/2014

Author(s):  
Shalini Jhanji ◽  
Madhu Dhingra

The germination behaviour of unsoaked, hydroprimed and thiourea primed seeds (TU,750, 1000 and 1250 ppm) in water , polyethylene glycol (PEG, -0.2 and -0.4 MPa ) and NaCl (30 and 50 mM) was investigated. The percent germination and seedling growth of TU primed seeds was best compared to other treatments under stressed conditions. The root/shoot ratio increased with stress in all seedlings and vice versa for seedling vigour index. TU primed seeds exhibited the highest tolerance index (85) under - 0.2 MPa PEG treatment and 40 tolerance index under 30mM salinity stress. Priming with thiourea @1000 ppm was the most effective in ameliorating water and salinity stress.


2013 ◽  
Vol 39 (12) ◽  
pp. 2228 ◽  
Author(s):  
Ye FENG ◽  
Feng GUO ◽  
Bao-Long LI ◽  
Jing-Jing MENG ◽  
Xin-Guo LI ◽  
...  

1965 ◽  
Vol 7 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Miroslav Penka
Keyword(s):  

2021 ◽  
Author(s):  
Xuhui Zhou ◽  
Lingyan Zhou ◽  
Yanghui He ◽  
Yuling Fu ◽  
Zhenggang Du ◽  
...  

Abstract Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. Recent studies suggest that climate warming can differentially affect root and shoot biomass, and subsequently alter root: shoot ratio. However, warming effects on root: shoot ratio and their underlying drivers at a global scale remain unclear. Using a global synthesis of >300 studies, we here show that warming significantly increases biomass allocation to roots (by 13.1%), and two factors drive this response: mean annual precipitation of the site, and the type of mycorrhizal fungi associated with a plant. Warming-induced allocation to roots is greater in relatively drier habitats compared to shoots (by 15.1%), but lower in wetter sites (by 4.9%), especially for plants associated with arbuscular mycorrhizal fungi compared to ectomycorrhizal fungi. Root-biomass responses to warming predominantly determine the biomass allocation in terrestrial plants suggesting that warming can reinforce the importance of belowground resource uptake. Our study highlights that the wetness or dryness of a site and plants’ mycorrhizal associations strongly regulate terrestrial carbon cycle by altering biomass allocation strategies in a warmer world.


2011 ◽  
Vol 35 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Fernanda Carlota Nery ◽  
Hilton Morbeck de Oliveira ◽  
Amauri Alves de Alvarenga ◽  
Sara Dousseau ◽  
Evaristo Mauro de Castro ◽  
...  

Ecophysiological studies under semi-controlled conditions in nurseries and greenhouses are essential to enable the use of native species to recover degraded areas and for commercial planting. Talisia subalbens (Mart) Radlk, 'cascudo', is a native fruiting species of the Cerrado on the verge of extinction. The ecophysiological performance of this species was evaluated in nursery conditions under different levels of shading (full sunshine, 30%, 50% and 70%). Initial growth, biomass allocation, gas exchange and chlorophyll content of the plants were analyzed. Full sunshine cultivated plants showed a higher accumulation of total, shoot, and root dry biomass. There was no significant difference in the root/shoot ratio among the treatments. Seedlings cultivated under full sunshine and 30% shading showed higher values for height, basal diameter, and leaf area. Differences in stomata conductance and photosynthesis rate were not observed among the different shading levels. Plants cultivated under 70% of shading had higher contents of chlorophyll a, b, and total. During the initial phase with higher levels of radiation were fundamental for the development of T. subalbens seedlings.


2015 ◽  
Vol 33 (1) ◽  
pp. 01-12 ◽  
Author(s):  
F.F. CORRÊA ◽  
R.H. MADAIL ◽  
S. BARBOSA ◽  
M.P. PEREIRA ◽  
E.M. CASTRO ◽  
...  

The objective of this work was to evaluate the effects of the population density of Typha angustifolia plants in the anatomical and physiological characteristics. Plants were collected from populations of high density (over 50% of colonization capacity) and low density (less than 50% of colonization capacity) and cultivated under controlled greenhouse conditions. Plants from both populations were grown in plastic trays containing 4 L of nutritive solution for 60 days. At the end of this period, the relative growth rate, leaf area ratio, net assimilatory rate, root/shoot ratio, leaf anatomy, root anatomy, and catalase and ascorbate peroxidase activities were evaluated. Plants from high density populations showed increased growth rate and root/shoot ratio. Low density populations showed higher values of stomatal index and density in leaves, as well as increased palisade parenchyma thickness. Root epidermis and exodermis thickness as well as the aerenchyma proportion of high density populations were reduced, these plants also showed increased vascular cylinder proportion. Only catalase activity was modified between the high and low density populations, showing increased values in low density populations. Therefore, different Typha angustifolia plants show differences in its anatomy and physiology related to its origins on high and low density conditions. High density population plants shows increased growth capacity related to lower apoplastic barriers in root and this may be related to increased nutrient uptake capacity.


2020 ◽  
Vol 11 ◽  
pp. e3400
Author(s):  
Genilson Lima Diniz ◽  
Reginaldo Gomes Nobre ◽  
Geovani Soares de Lima ◽  
Leandro de Pádua Souza ◽  
Lauriane Almeida dos Anjos Soares ◽  
...  

The semiarid region of Northeastern Brazil is characterized by long drought periods, and the use of saline waters appears as an alternative for the expansion of irrigated areas. Associated with the use of these waters, silicon fertilization constitutes an important attenuator of salt stress. In this perspective, this study aimed to evaluate the phytomass production and quality of the passion fruit cultivar ‘Gigante Amarelo’ grown with saline water and silicon fertilization. The experiment was conducted in a plant nursery belonging to the Center of Agrifood Science and Technology, in the municipality of Pombal-PB. A completely randomized block design in a 5 x 5 factorial scheme was used, referring to five levels of electrical conductivity of the irrigation water (0.3, 1.0, 1.7, 2.4, and 3.1 dS m-1) and five doses of silicon fertilization (0; 25; 50; 75, and 100 g of potassium silicate/plant), with four replications and two plants per plot. The phytomass accumulation (leaves, stem, and roots), as well as the total dry phytomass, shoot dry phytomass, root/shoot ratio, and the quality index of Dickson were evaluated. The data obtained were subjected to the F-test at 0.01 and 0.05 level of probability. The electrical conductivity of water from 0.3 dS m-1 caused the decrease of phytomass production in seedlings of the passion fruit cultivar ‘Gigante Amarelo’, although it is possible to produce good quality passion fruit seedlings with water salinity up to 3.1 dS m-1. The doses of silicon fertilization mitigated the effect of salt stress on the root/shoot ratio of plants of the passion fruit cultivar ‘Gigante Amarelo’.


2018 ◽  
Vol 35 (0) ◽  
Author(s):  
A. ZOHAIB ◽  
T. TABASSUM ◽  
S.A. ANJUM ◽  
T. ABBAS ◽  
U. NAZIR

ABSTRACT: Weeds associated with crops may impose their phytotoxic effects on crop plants through the release of their allelochemicals and hence seriously reduce crop productivity. The present study was conducted to investigate the allelopathic effect of water soluble phenolics of weeds associated with wheat crop (Vicia sativa, Trigonella polycerata, Lathyrus aphaca, Medicago polymorpha, Melilotus indica) on germinability and biomass production of wheat seedlings by using their water extracts at 2.5% (w/v) and 5% (w/v) concentrations and residues of the same weeds with 0, 15 and 30 d decomposition periods at 2% (w/w) concentration. The results showed that the water extracts of M. indica and V. sativa at 5% concentration imposed the most inhibitory effect on energy of germination (81%) and prolonged time to 50% germination (226%), respectively; by contrast, T. polycerata and M. indica extracts at the same concentration inhibited shoot (8%) and root fresh biomass (64%). However, shoot dry biomass was exalted by the weed extracts at both concentrations with maximum increase (29%) caused by the M.indica extract at 2.5% concentration; however, root dry biomass (46%) and root/shoot ratio (51%) were decreased by M. polymorpha and M. indica extracts at 5% concentration, respectively. Residues of L. aphaca and M. polymorpha with a 30 d decomposition period proved the most toxic regarding energy of emergence (85%) and time to 50% emergence (138%), respectively; while, shoot fresh (41%) and dry biomass (26%) production were hindered mostly by M. indica and M. polymorpha residues with a 30 d decomposition period. There was the highest decrease in root fresh (64%) and dry biomass (64%), and root/shoot ratio (64%) when treatment was performed with V. sativa residues without decomposition. The results show that leachates and residues of weeds inhibit wheat germinability and biomass production through release of allelochemicals, and they are a threat to profitable crop production.


1971 ◽  
Vol 19 (1) ◽  
pp. 39 ◽  
Author(s):  
PB Preece

Investigations into the germination behaviour of seed of the widespread Australian arid zone leguminous tree Acacia aneura Benth. are described. Hardseededness has been overcome in routine laboratory studies, but attempts to understand the mechanism by which it is overcome in nature were unsuccessful. The seed germinates equally well in the dark and in the light within the temperature range 15-36°C. Temperatures between 20 and 30° are optimal for germination, and carbon dioxide concentrations up to 5 % increase the germination rate above that displayed in ambient air. A simple model has been developed which suggests that seed of this species should have been available and should have germinated in c. one year in every nine, since records began in parts of western New South Wales where mulga regeneration is absent.


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