scholarly journals SEED DORMANCY BREAKING TREATMENTS FORAFRICAN PURSLANE (Zaleya pentandra)

2015 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
S. MUNAWAR ◽  
M. NAEEM ◽  
H.H. ALI ◽  
M. JAMIL ◽  
M. IQBAL ◽  
...  

ABSTRACT Understanding the mechanisms involved in releasing seed dormancy is crucial for effective plant management and renewal of species in the arid zone. Zaleya pentandra is an emerging invasive weed of the arid areas of Pakistan. We investigated the effects of different dormancy breaking treatments on the germination of Z. pentandra seeds. Seeds were treated with hot water (by placing them in boiling water for 5, 15, 30, 60, 90, 120, and 150 min), dry heat (by placing them in a preheated oven at 70 oC for 1, 2, and 4 hours; at 70 oC for 1, 2, 3, and 4 days, and at 200 oC for 5, 10, 15, 30, and 45 min) and stratification (by placing them at 2-5 ºC in a refrigerator for 5, 10, 30, and 60 min; for 3, 6, and 12 hours, and for 1, 2, 4, 8, 15, and 30 days). Seeds also were soaked in thiourea ([(NH2)2CS] (0, 2,500, 5,000, 7,500, and 10,000 mg L-1 for 24 h at 30 oC) and in KNO3 (0, 10,000, 20,000, 30,000, 40,000, 50,000, and 60,000 mg L-1 for 24 h at 30 oC). Additionally, seeds were scarified with HCl (for 3, 6, 9, 12, 15, 18, and 21 h), HNO3 (for 3, 6, 9, 12, 15, 18, and 21 h), and H2SO4 (for 20, 40, 60, 80, 100, and 120 min at 30 oC) and also mechanically scarified with sandpaper. Zaleya pentandra seeds showed typical signs of hard seed coat dormancy. Mechanical scarification and acid treatments promoted seed germination to a varying degree. Seed scarification with HNO3 for 12 to 18 h as well as with HCl for 12 h and 15 h was efficient in breaking dormancy of Z. pentandra seeds, providing germination up to 92.5%. Seed scarification with H2SO4 from 20 to 120 min showed little effect, whereas hot water, dry heat, stratification and various concentrations of thiourea and KNO3 were ineffective in breaking Z. pentandra seed dormancy.

2001 ◽  
Vol 79 (2) ◽  
pp. 197-203 ◽  
Author(s):  
David J Susko ◽  
J Paul Mueller ◽  
Janet F Spears

We evaluated several methods for breaking dormancy in seeds of the invasive weed Pueraria lobata (Willd.) Ohwi (kudzu). Seedlings from untreated seeds emerged from late March to early October 1999 in trays placed outdoors under natural weather conditions; mean cumulative percentage emergence was low (11%). In growth chamber experiments, germination percentages of untreated seeds ranged from 6 to 17%. All hand-scarified seeds germinated, whereas only 6% of intact seeds germinated. Other dormancy-breaking methods that produced higher germination percentages included exposure to ethyl alcohol for 6-12 h (24-86%), exposure to concentrated sulfuric acid for 1-2 h (65-81%), and exposure to moist heat for 5-300 s (30-80%). The influence of temperature on germination percentages of seeds following dry heat treatments depended on the duration of exposure. At 60 and 80°C, germination percentages increased with longer exposures to dry heat and were greatest after 720 min (27 and 60%, respectively). At 100°C, percent germination was greatest when seeds were exposed to dry heat for only 10 min (93%). Cold stratification at 5°C for 0-6 weeks did not increase seed germination percentages after exposure to a range of alternating thermoperiods. Similarly, dry storage at room temperature for 0, 200, or 400 days did not affect germination percentages in light or dark treatments.Key words: Pueraria lobata, physical dormancy, germination, phenology, acid scarification, warm stratification, cold stratification.


2020 ◽  
Vol 48 (1) ◽  
pp. 37-43
Author(s):  
Maryati Sari ◽  
Satriyas Ilyas ◽  
M. Rahmad Suhartanto ◽  
Abdul Qadir

Bambara groundnut seeds often show unsynchronized and slow germination even though on newly harvested seeds. This might be due to the presence of seed dormancy. Therefore, the objective of this research was to obtain the information on seed dormancy and germination behaviour of bambara groundnut seeds during desiccation. The experiment was arranged in a nested design. Dormancy breaking treatments (untreated, mechanical scarification, soaking in 1% KNO3 for 2 hours, mechanical scarification followed by KNO3 soaking) were nested in each of the desiccation levels (fresh seeds with 54.7% moisture content (mc), desiccated seeds with 44.4%, 18.0%, 15.4%, and 12.1% mc). The results showed that newly harvested seeds were in dormant state. Seed desiccation did not increase the intensity of seed dormancy, even resulted in an increase in field emergence (at 30 days after planting) from 43.9% in fresh seeds to around 70% in dry seed (12-15% mc). Seed desiccation (from 44.4% mc to 12.1% mc) increased the field emergence, although it was inadequate to break the dormancy completely. Meanwhile, seed desiccation tended to increase the GA/ABA ratio, but the seed permeability was decreased. The fact showed that seed desiccation reduced the intensity of dormancy of bambara groundnut seed, therefore, it is suggested to modify the drying method in order to accelerate the increasing of GA/ABA ratio while keeping the testa permeable. Keywords: after-ripening, GA/ABA ratio, hard seed, kacang bogor, permeability


Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 319
Author(s):  
Yuhan Tang ◽  
Keliang Zhang ◽  
Yin Zhang ◽  
Jun Tao

Sorbus alnifolia (Siebold & Zucc.) K.Koch (Rosaceae) is an economically important tree in the temperate forests of Eastern China. In recent decades, ever-increasing use and modification of forestlands have resulted in major degeneration of the natural habitat of S. alnifolia. Moreover, S. alnifolia seeds germinate in a complicated way, leading to a high cost of propagation. The current study aimed to determine the requirements for breaking seed dormancy and for germination as well as to characterize the type of seed dormancy present in this species. Moreover, the roles of temperature, cold/warm stratification, and gibberellic acid (GA3) in breaking dormancy were tested combined with a study of the soil seed bank. The results showed that intact seeds of S. alnifolia were dormant, requiring 150 days of cold stratification to achieve the maximum germination percentage at 5/15 °C. Exposure of the seeds to ranges of temperatures at 15/25 °C and 20/30 °C resulted in secondary dormancy. Scarifying seed coat and partial removal of the cotyledon promoted germination. Compared with long-term cold stratification, one month of warm stratification plus cold stratification was superior in breaking dormancy. Application of GA3 did not break the dormancy during two months of incubation. Seeds of S. alnifolia formed a transient seed bank. The viability of freshly matured S. alnifolia seeds was 87.65% ± 11.67%, but this declined to 38.25% after 6-months of storage at room temperature. Seeds of S. alnifolia have a deep physiological dormancy; cold stratification will be useful in propagating this species. The long chilling requirements of S. alnifolia seeds would avoid seedling death in winter.


2018 ◽  
Vol 40 (3) ◽  
pp. 237-245
Author(s):  
Breno Marques da Silva e Silva ◽  
Camila de Oliveira e Silva ◽  
Fabiola Vitti Môro ◽  
Roberval Daiton Vieira

Abstract: Ormosia paraensis Ducke has ornamental seeds widely used in the manufacture of bio-jewels and wood used in the furniture industry. For seedling production, the information on its seed physiology is scarce. Thus, the aim of this study was to assess methods for breaking dormancy and relate them to integument structure and water uptake by O. paraensis seeds. Seed dormancy-breaking was performed by mechanical scarification and soaking in sulfuric acid for 0, 15, 30, 60, 120, and 240 minutes. Dormancy‐broken seeds were compared with intact seeds. Seed integument is formed by a cuticle (hydrophobic substances), epidermis (macroesclereids of the palisade layer,), hypodermis (osteosclereids), and parenchyma cells. Intact seeds did not absorb water after 72 hours of soaking. The highest percentages and rates of seed germination were observed in treatments with mechanical scarification and soaking in sulfuric acid for 60 or 120 minutes. Seed soaking in sulfuric acid (H2SO4 p.a. 98.08%) for 60 or 120 minutes or mechanical scarification are adequate to overcome physical dormancy associated with O. paraensis seed integument impermeability to water or gases.


2016 ◽  
Vol 49 (4) ◽  
pp. 27-34
Author(s):  
G. Gogoi ◽  
P.K. Borua ◽  
D. Chetia

Abstract Abelmoschus moschatus Medik. subsp. moschatus is a wild uncultivated variety of common lady’s finger (Abelmoschus esculentus) possessing a high degree of seed dormancy. Methods of dormancy breaking in the seed of the plant were investigated through different physical and chemical methods. Different preconditioning treatments including hot water, dry heat, physical scarification and chemical treatments including exogenous GA3 were applied to explore the initiation in germination. Seeds were germinated under the controlled photoperiod and temperature. The viability of the test seeds was estimated by topographical 2, 3, 5-Triphenyltetrazolium chloride (TTC) solution test. Highest germination percentage was obtained in the seeds treated with the exothermic reaction of H2SO4 and H2O, followed by exposure to gibberellic acid (GA3). The exposure time of exogenously applied GA3 had a significant influence on the germination response. The optimum germination temperature was found to be 30 ± 0.5°C. Treatment with 0.75% of 2, 3, 5-Triphenyltetrazolium chloride solution for 4 h at 35 ± 0.5°C enabled to correlate the viability of the seeds with the germinative values. Maximum germination was induced through this technique and dormancy of the seed can be attributed due to hard impermeable seed coat and endogenous physiological factor.


2006 ◽  
Vol 28 (2) ◽  
pp. 179 ◽  
Author(s):  
N. Chikumba ◽  
C. Mapiye ◽  
X. Poshiwa

Methods for breaking hard seed to allow germination of 2 seedlots of Macrotyloma daltonii (Webb) Verdc., were investigated. Treatments included soaking, application of dry heat, hot water, acid scarification, sand paper scarification, pre-chilling, alone and in combination with acid and dry heat. The treated seeds were tested for germination over 21 days in an incubator with 12 h of light and 12 h of darkness and temperatures of 25 and 18°C during the light and dark phases, respectively. A 20-min exposure to 98% concentrated sulphuric acid was most effective in increasing germination from 10 to 80% in seedlot 1. The 10-min acid treatment increased germination from 21 to 38% in seedlot 2, but 20 min reduced germination and increased the number of dead seeds. Seedlot 1 had greater levels of hard seed (88%) than seedlot 2 (61%). Soaking, hot water, dry heating, pre-chilling, or sandpaper scarification were not effective in breaking hard seed in either seedlot 1 or 2. Combining pre-chilling with 10 min of acid treatment damaged seed and impaired germination across the 2 seedlots. The range of pre-sowing seed treatments that indicated positive effects on germination, particularly acid treatments need to be further investigated in the field under different pedo-climatic conditions to allow appropriate rangeland management options to be developed.


2021 ◽  
Vol 9 (1) ◽  
pp. 43-58
Author(s):  
Nazhira Firda Yulia ◽  
◽  
Supriyanto Supriyanto ◽  
Diana Prameswari ◽  
◽  
...  

Screw tree is a shrub from family Malvaceae that has many benefits in pharmacy. Screw tree seed has very hard seed coat, so the seed must be treated before germination. The aim of this research was to assess the characteristic of fruit and seeds, effect of seed breaking dormancy, and effect of NPK fertilizer dosage on the growth of screw tree (Helicteres isora) seedlings. The results indicated that screw tree fruits belong to dry fruits with capsule form and has 5 follicles that has different direction. Screw tree seed is orthodox type that has 9 ̶ 36 seeds in one follicle with triangle and square shape. Germination technique in laboratory with soaking the seeds in hot water 100oC until the water cool for 48 hours treatment produced the best germination amounting to 65.0%. Germination technique in green house with soaking the seeds in hot water 100oC until the water cool for 24 hours treatment was the best germination amounting to 77.0%. Seedlings fertilized with 1 g NPK doses increased screw tree growth in diameter parameter of 6.35 mm and shoot-root ratio parameter of 3.9 compared to control.


Akta Agrosia ◽  
2016 ◽  
Vol 19 (2) ◽  
pp. 147-156
Author(s):  
Yesi Uyatmi ◽  
Entang Inoriah ◽  
Marwanto Marwanto

Seed of Caesalpinia bonduc L. is difficult to germinate due to the thick and hard seed coat. The research aims to evaluate various methods for breaking dormancy of C. bonduc seed. This study was conducted from December to January 2016 The way to break the dormancy were arranged in Completely Randomized Design. Eleven methods to solve the seed dormancy of C. bonduc were compared. The ways to break the dormancy were soaking in water with different temperatures. The temperatures were 30C for 0 hours, 5 hours, 10 hours, and 15 hours. Other techniques to break the dormancy were soaking in hot water at 10000C for 5 hours, 10 hours, and 15 hours. Warm stratification with 100% air humidity (RH) at 40C for five days, ten days and 15 days also included as treatments. The last method was seed piercing with a needle. The variables observed in this study were germination capacity, germination rate, epicotyl length, plant height, and root length. The results of this study showed that the 11 methods of breaking seed dorman cy significantly affected germination capacity, germination rate, emerging epicotyl, and plant height. Seed piercing classified as the most efficient method as indicated by the value of 100% in germination capacity, 1.43 in germination rate, 13.64 cm in plant height, and 6.16 cm in root length.0


1994 ◽  
Vol 74 (1) ◽  
pp. 19-24 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson

Effects of immersing dry seeds in KOH and NaOH solutions on seed dormancy and water uptake were studied in three dormant lines of wild oat (Avena fatua L.). KOH was more effective than NaOH in breaking dormancy. Maximum dormancy-breaking effect of 5.3 N KOH could be achieved with a 10- or 15-min treatment. Increase in treatment time did not necessarily increase germination; rather, it caused damage to the seeds. For 10-min treatment, 5.3 and 7.6 N KOH solutions were more effective than 3 and 9.8 N. Genetic lines responded differently to the KOH treatment. Initial rate and amount of water uptake by KOH-treated seed were significantly higher than by the untreated. It is believed that breaking dormancy by the alkaline treatment is related to removing the barrier to water uptake formed by the seed coat. Key words: Alkalis, Avena fatua, dormancy, seed coat, seedling growth


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