The effects of vegetation development upon achene production in the woody weed, groundsel bush (Baccharis halimifolia L.)

1979 ◽  
Vol 30 (6) ◽  
pp. 1053 ◽  
Author(s):  
FD Panetta

An examination of the achene production of groundsel bush (Baccharis halimifolia L.) populations growing within two exotic softwood stands of differing ages revealed that substantial reductions in this variable occurred following canopy closure. Mean reproductive efficiency, estimated as the number of achenes per gram dry weight of understorey bushes within the older stand, was only 31% of the corresponding value for bushes growing within a stand prior to the occurrence of canopy closure. Only small differences were found in both cumulative germination percentage and germination rate of achenes collected from each population. Female bushes, when shaded to a level of 14% open sky radiation, demonstrated a 30% reduction in the number of flowers initiated per head and a 25% reduction in percentage achene fill. Floral initiation was found to be independent of the production of oil reserves. Whilst dramatic reductions in the achene production of understorey individuals occur with plantation development, it is suggested that the density of unmanipulated populations of B. halimifolia may prevent the invasion and development of dominance by native tree species.

2018 ◽  
Vol 51 (3) ◽  
pp. 51-68 ◽  
Author(s):  
M.K. Hasan ◽  
M.S. Islam ◽  
M.R. Islam ◽  
H.N. Ismaan ◽  
A. El Sabagh

Abstract A laboratory experiment regarding germination and seedling growth test was conducted with three black gram genotypes tested under three salinity levels (0, 75 and 150 mM), for 10 days, in sand culture within small plastic pot, to investigate the germination and seedling growth characteristics. Different germination traits of all black gram genotypes, like germination percentage (GP), germination rate (GR), coefficient of velocity of germination (CVG) greatly reduced, as well as mean germination time (MGT) increased with increasing salt stress. At high salt stress, BARI Mash-3 provided the highest GP reduction (28.58%), while the lowest was recorded (15.79% to control) in BARI Mash-1. Salinity have the negative impact on shoot and root lengths, fresh and dry weights. The highest (50.32% to control) and lowest reduction (36.39%) of shoot length were recorded in BARI Mash-2 and BARI Mash-1, respectively, under 150 mM NaCl saline conditions. There were significant reduction of root lengths, root fresh and dry weight, shoot length, shoot fresh and dry weight in all genotypes under saline condition. The genotypes were arranged as BARI Mash-1 > BARI Mash-3 > BARI Mash-2, with respect to salinity tolerance.


2017 ◽  
Vol 9 (2) ◽  
pp. 242-249 ◽  
Author(s):  
Faride BEHBOUDI ◽  
Zeinalabedin TAHMASEBI SARVESTANI ◽  
Mohamad Zaman KASSAEE ◽  
Seyed Ali Mohamad MODARES SANAVI ◽  
Ali SOROOSHZADEH

Plants such as wheat and barley that are strategically important crops need to be considered to develop a comprehensive toxicity profile for nanoparticles (NPs). The present study was aimed to investigate the effects of chitosan and SiO2 NPs on wheat and barley plants. Two factorial experiments (seeds priming and direct exposure) were performed based on a completely randomized design in four replications. Results showed that the seeds priming with the NPs had not significant effect on germination parameters such as Germination Percentage (GP), Germination Rate (GR), Germination Value (GV), Mean Germination Time (MGT), Pick Value (PV) and Mean Daily Germination (MDG). In contrast, exposure of the seeds to the NPs had significant effects on these parameters. In both experiments, treatments had significant effects on shoot, seedling, root length, fresh and dry weight, as well as vigor indexes as compared to the control. In most traits, the best concentration of NPs was 30 ppm, whereas applications of the NPs with 90 ppm displayed adverse effects on majority of the studied traits. According to these results, selectivity in applications of NPs with suitable concentration and method is essential for different plant species.  


2013 ◽  
Vol 5 (1) ◽  
pp. 5-18
Author(s):  
Alireza Pourmohammad ◽  
Fariborz Shekari ◽  
Veeda Soltaniband

Abstract An experiment was concluded to evaluate the effects of priming on germination characteristics and establishment of rapeseed seedlings during three stages. In the first and second stages of experiment, the effects at three factors vis: cultivars (RVS, Hayola), waterdeficit stress (Control,-6 and -12 bar) and cycocel treatment (dry seeds, 300, 600, 900, 1200 and 1500 μM) on germination and seedling growth of plant were assayed. The results showed that priming had positive effects on germination percentage, germination rate index, germination index, and radicle length under water-deficit conditions. RVS had greater efficiency than other cultivars. The third section of experiment revealed that the priming of RVS seeds improved the stem, root and dry weight, total dry weight as well as leaf number and area of seedlings.


2018 ◽  
Vol 10 (2) ◽  
pp. 409-416
Author(s):  
Ratri Tri Hapsari ◽  
Trustinah Trustinah

Salinity is a major abiotic stress limiting mungbean production worldwide including Indonesia. Since mungbean plant is very sensitive to salt condition, selection of salinity tolerant genotypes becomes important for mungbean improvement. The objective of this study was to evaluate the tolerance of eight mungbean genotypes to salinity at seedling stage under different levels. The experiment was arranged in a randomized complete block design with two factors (mungbean genotypes and salinity levels) and triplicates. Observation variables were germination percentage, vigor index, germination rate, hypocotyls length, epicotyls length, root length, number of root, seedling fresh weight, and seedling dry weight. The result showed that increasing level of salinity concentration inhibited the speed of germination, germination percentage, vigor index, normal seedling fresh weight, and number of lateral roots. Murai and Vima 1 were identified as tolerant genotypes, while Vima-2 and MLGV 0180 were identified as salinity sensitive genotypes at seedling stage. Currently, mungbean varieties with special characters, such as saline-tolerant is not yet available. The availability of saline-tolerant variety of mungbean is a cheaper and easier technology for farmers to anticipate the expansion of the saline area. The tolerant genotypes may be further tested at the later stage to obtain promising genotype tolerant to salinity that effectively assist mungbean breeding program.


HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 186c-186
Author(s):  
Janine O. Haynes ◽  
Wallace G. Pill

Purple coneflower seeds following priming (-0.04 MPa, 10 days, 15C, darkness) osmotically in polyethylene glycol 8000 (PEG) or matrically in expanded no. 5 vermiculite had greater germination rate and synchrony at continuous 20C or 30C than untreated seeds, but germination percentage was unaffected. Inclusion of 5.5 × 10-2 M gibberellic acid (GA3 as ProGibb Plus 2X, Abbott Laboratories, N. Chicago, Ill.) further improved germination rate and synchrony at 20C, but not at 30C. In a greenhouse study (30C day/27C night, July-August natural light), seeds primed in PEG or vermiculite containing G A3 compared to untreated seeds had 6 percentage points higher maximum emergence (ME), 3.3 fewer days to 50% ME, 1.9 fewer days between 10% and 90% ME, 116% greater shoot dry weight, and 125% longer leaves at 16 days after planting in peat-lite. Inclusion of ethephon (0.01 m, as Florel) either alone or with GA3 during priming provided no benefit to seed germination or seedling emergence. Moistened vermiculite substituted for PEG solution as a priming medium for purple coneflower seeds, the priming benefit on seedling emergence and growth being enhanced by 5.5 × 10-2m G A3 inclusion in the priming media.


2015 ◽  
Vol 9 (1) ◽  
pp. 6-11
Author(s):  
Abolfazl Masoumi Zavariyan ◽  
Mojtaba Yousefi Rad ◽  
Mohsen Asghari

For investigation of the effect of seed priming by kinetin on germination indices and proline activity of Silybum marianum  L. under drought stress, factorial experiment based on completely randomized design with two factor includingdifferent concentrations of kinetin (0, 10 and 20 ppm) and different levels of drought stress including 0, -6 and -12 barat three replicates was carried out. According to the results, drought stress and kinetin individualy cause to decreases of germination percentage, germination rate, seedling length, seed vigor and seedling dry weight but uses of kinetin in drought stress condition improvment of them. Also, drought stress cause to increases of proline content and catalase activity. Therefore, seed priming with 10 ppm kinetin at drought stress was improved the germination indices of Silybum marianum L.DOI: http://dx.doi.org/10.3126/ijls.v9i1.11919 International Journal of Life Sciences Vol.9(1) 2015 6-11


1970 ◽  
Vol 5 (1) ◽  
pp. 104-112
Author(s):  
Arya Agung Pranata ◽  
Asil Barus ◽  
Meiriani

The problem of generative propagation of soursop is its seeds take a long time to germinate which are caused by the hard seed coat. The solution to solve that problem is scarification and coconut water soaking to simply the process of imbibition and seed germination and also stimulate the growth of shoot. This objective of the research was to determine the effect of the scarification position and the soaking with various concentrations of coconut water on seed germination and growth of soursop seedling. This research was held at the Faculty of Agriculture field, the University of Sumatera Utara in March - July 2017. The research used a factorial randomized block design with two factors and three replication. The first factor is the scarification position (without scarification, stomach scarification, top scarification) and the second factor is coconut water soaking (0%; 25%; 50%; 75 %). The result of the research showed that the germination rate parameter, germination percentage, crop height, number of leaves, root volume and dry weight of crop significantly higher on without scarification treatment than with scarification treatment. The interaction between the scarification position and soaking with various coconut water concentrations was not significantly affecting the seed germination and growth of soursop seedling.


2021 ◽  
Vol 911 (1) ◽  
pp. 012086
Author(s):  
Ramlah Arief ◽  
Fauziah Koes ◽  
Oom Komalasari ◽  
Fatmawati

Abstract Seed priming or invigoration is presowing treatments of improving germination aimed to reduce the time from sowing to emergence and improving emergence uniformity. Research on seed priming was conducted Indonesian Cereal Research Institute (ICERI) seed laboratory from January until March 2021 to evaluate the effect of seed priming on sorghum seed vigor. Seed quality parameters includes germination percentages, germination rate, shoot and primary root length, seedling dryweight, Sorghum seed variety of Suri 4 were used as seed material. Results showed that among the priming treatments that give positive effect on germination percentage, germination rate, seedling dry weight were priming treatment with KNO3 1.5%.


2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Ekosari Roektiningroem ◽  
Purwanti Widhy

This research aims to to know the seed viability of the two dates on the market. It has been done from July to November 2014, in the laboratory of  Mathematics and Natural Science Faculty, Yogyakarta State University. The type of Dates seeds are Sayer (oval-cilindrical, ±3cm, dark orange brown/more light than another),  and Lulu (round, ±2cm, dark maroon reddish /more dark than Sayer’s). Viability test by germination testing; conducted on plastic tray with cotton sheet and fabric covered; fill with 100 grains of seeds. Repeated 4 times. Incubation at room temperature (±30oC). The parameters were seed fresh weight, seed dry weight, seed moisture, germination percentage and germination rate. The results were analyzed by compare mean - independent samples t test of SPSS 18’th. The results showed that the viability of both of Date’s seeds from local’s market (Sayer and Lulu) is high. Sayer’s have better viability than Lulu’s (due to the germination percentage and germination rate). Keywords: date seed, viability test, germination test


2015 ◽  
Vol 71 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Hamid-Reza Fallahi ◽  
Golsoom Fadaeian ◽  
Marziyeh Gholami ◽  
Omolbanin Daneshkhah ◽  
Fatemeh Sadat Hosseini ◽  
...  

Abstract The use of genetic potential of forgotten plants such as grasspea and arugula is an appropriate strategy for increasing of plants tolerance to environmental stresses. Therefore, in this laboratory study the effects of different levels of osmotic (0, -2, -4, -6, -8, -10, -12 and -14 bar caused by PEG) and salinity (0, 50, 100, 150, 200, 250, 300 and 350 mmol induced by NaCl) stresses were evaluated on germination indices of grasspea and arugula in four separate experiments. Arugula showed a suitable tolerance to osmotic stress, so that its germination percentage and rate at treatment of -10 bar were similar to control. Arugula had 79% germination at osmotic level of -14 bar, but its germination rate at this level was 60% lower than control. In addition, its radicle length until -8 bar and radicle dry weight up to -14 bar were higher than control treatment. However, all levels of salinity stress particularly treatments of more than 100-150 mmol decreased the germination indices of arugula. Germination percentage of arugula in 150 and 200 mmol treatments was 22 and 56% lower than control treatment, respectively. Grasspea had partially suitable tolerance to osmotic stress until -6 bar, but then intensified the reducing trends of its germination indices and finally reached to zero at -14 bar treatment. Moreover, salinity stress especially treatments of higher than 100 mmol decreased all germination indices of grasspea. Overall, arugula was a more tolerant plant especially to osmotic stress; therefore this forgotten plant can be used in agronomic and breeding programs in areas affected by drought stress.


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