Seed Germination Physiology of Eucalyptus delegatensis R. T. Baker in Tasmania

1993 ◽  
Vol 41 (1) ◽  
pp. 119 ◽  
Author(s):  
M Battaglia

The seed germination response of seedlots from five geographically disparate provenances of Eucalyptus delegatensis to temperature, stratification, soil matric potential, relative humidity and interrupted imbibition was examined. The species was found to have a distinct temperature optimum of between 15 and 20°C, and a minimum temperature for germination of approximately 2°C. Short periods of exposure to high temperatures did not substantially affect germination performance. Stratification greatly increased the range of temperatures over which a high proportion of the seed germinated. Increases in the rate of germination with stratification are related to accrued thermal time during stratification. Pre-imbibing seeds at water potentials down to -2 MPa increased the rate of germination; however, no advantage was found after pre-imibibing at -3 MPa. This increased germination rate was associated with a shortening of the time to commencement of germination and more synchronous germination. Germination rate and germination capacity were impeded by soil matric potentials below -0.01 MPa, and germination was totally inhibited by soil matric potentials below -0.5 MPa. Soil matric potential and temperature interacted in their effects on germination capacity, and seeds germinating at near optimum temperatures were less sensitive to soil moisture stress. Seeds survived dehydration within 60 h of the commencement of imbibition, but were increasingly affected by dehydration thereafter. The rate of imbibition was influenced by the ambient temperature and solution water potential. At modest levels of water stress, imbibition was not impeded and the reduction in germination capacity was probably due to the inhibition of growth related processes. Differences in germination response were detected between the seedlots and these could be related to the geographic origin of the seedlots.


Soil Research ◽  
1968 ◽  
Vol 6 (2) ◽  
pp. 179 ◽  
Author(s):  
N Collis-George ◽  
J Williams

The matric potential contributes positively to the isotropic effective stress operating in the solid framework of a soil system. Collis-George and Hector (1966) suggested that the matric potential may influence seed germination through its contribution to the effective stress in the solid framework surrounding the seed. Experiments are described which separate the effects of matric potential on seed germination into those that can be attributed to the free energy of the soil water and those that can be attributed to the effective stress in the soil system. The results clearly indicate that (1) seed germination is influenced by the isotropic effective stress in the solid framework of the soil system, and (2) the influence of matric potential on seed germination in the range 0 to - 400cm of water can be wholly attributed to the isotropic effective stress in the solid framework and not to the free energy of the soil water as defined by the matric potential. These conclusions are discussed in terms of the behaviour of other organisms in response to an applied matric potential.



2014 ◽  
Vol 92 (2) ◽  
pp. 281 ◽  
Author(s):  
Martha Cervantes ◽  
Eliane Ceccon ◽  
Consuelo Bonfil

<p><span style="font-size: medium;"><span style="font-family: Times New Roman;">Studies on propagation of trees of Tropical Dry Forests are scarce in Mexico, besides, the provenance of seeds used in reforestation programs is generally unknown or poorly addressed. Knowledge on seed germination patterns of different provenances, and how they change through time, is useful to identify adequate sources of seeds and to develop seed collection and storage programs under the low-tech conditions prevailing in most rural nurseries. We evaluated seed size variation and germination of stored seeds from three different provenances per species in <em>Acacia bilimekii</em>, <em>Haematoxylum brasiletto</em>, <em>Lysiloma acapulcense</em>, and<em> L. divaricatum</em>.<em> </em>Seeds were collected in four sites in the Tropical Dry Forest of Morelos, Mexico, and were stored at room temperature; seed size was estimated through the volume of 75 seeds per provenance/species. Seed germination tests were made periodically from six to 24 months after storage and the effects of provenance and storage time on germination were analyzed using Anovas. There were significant differences in seed size among provenances in all species, while the effect of provenance on germination rate was significant in three of them. Germination rate changed with storage time among species and provenances. After 24 months, germination capacity was still ≥ 50% in all provenances of the two <em>Lysiloma</em> species, but in <em>A.</em> <em>bilimekii</em> there were large differences among provenances. Mean germination capacity was low in <em>H. brasiletto</em> after six months. More research on seed germination and storage of a larger set of species and provenances is needed to restore the Mexican tropical dry forests. </span></span></p>



2018 ◽  
Vol 5 (2) ◽  
pp. 120
Author(s):  
Emmy Winarni ◽  
Adistina Fitriani ◽  
Purnomo Purnomo ◽  
Sudin Panjaitan Panjaitan

Good germination of rattan seed (DaemonoropsdracoBlume) will increase the germination rate, germination rate, and germination rate. However, to germinate undergoes any obstacles because the seed of jernangrattan has a period of dormancy. The immersion in cold water or at normal temperature (28o - 32o C) is one way that can be used to break the dormancy period of the seed. This study aims to determine the long immersion to the value of germination of rattan seed jernang (D. dracoBlume). This study used 3 treatments and 1 replication. The treatment in this research is soaking time without immersion (control), soaking for 24 hours, and 48 hours. The result research is that the long immersion has the effect on germination of rattan seed jernang (D. dracoBlume). The results showed that the best percentage of rattan seed germination (D.dracoBlume) got the preliminary treatment with water immersion for 24 hours with a percentage of 80%. The best seed germination rate is at 48 hours of water immersion treatment at 33.89% / day. The highest germination rate was found in seeds treated by water immersion for 48 hours with an average of 0.0122% / day.Keywords : germination capacity; rotan jernangPerkecambahan benih rotan jernang (Daemonorops draco Blume) yang baik akan meningkatkan daya kecambah, laju perkecambahan,dan nilai perkecambahan. Namun demikian untuk mengecambahkan masih terdapat kendala, karena benih rotan jernang memiliki masa dormansi. Perendam dalam air dingin atau pada suhu normal (28o - 32o C) merupakan salah satu cara yang dapat digunakan untuk mematahkan masa dormansi benih. Penelitian ini bertujuan untuk mengetahui lama perendaman terhadap nilai perkecambahan benih rotan jernang (D. draco Blume ). Penelitian menggunakan 3 perlakuan dan 1 ulangan. Perlakuan pada penelitian ini adalah waktu perendaman yaitu tanpa perendaman (kontrol), perendaman selama 24 jam, dan 48 jam. Hasil penelitian yang didapat adalah lama perendaman berpengaruh terhadap perkecambahan benih rotan jernang ( D. draco Blume ). Hasil penelitian menunjukkan bahwa persentase perkecambahan benih rotan jernan ( D.draco Blume ) yang terbaik yaitu yang diberikan perlakuan pendahuluan dengan perendaman air selama 24 jam dengan persentase sebesar 80%. Laju perkecambahan benih yang terbaik adalah pada perlakuan perendaman air selama 48 jam yaitu sebesar 33.89 %/hari. Nilai perkecambahan tertinggi terdapat pada benih yang diberikan perlakuan perendaman air selama 48 jam dengan rata – rata sebesar 0.0122 %/hari.Kata kunci : daya perkecambahan; rotan jernang



Jurnal Wasian ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 133-143
Author(s):  
Iskandar Siregar ◽  
◽  
Riki Ramdhani ◽  
Evayusvita Rustam ◽  
Dede Sudrajat ◽  
...  

Utilization of seeds storage results in decreased plant productivity. The increase can be used by treating seeds before planting through the technique of invigoration. This purpose of the study is to assess the effectiveness of invigoration methods using polyethylene glycol (PEG 6000) and ultrafine bubbles (UFB) to improve viability and vigor of sengon seeds (Falcataria moluccana). Seed agieng using 96 % ethanol was carried out to obtain the diversity of seedlot viability as the materials for testing the effectiveness of invigoration treatments. A complete random design was used to test the effectiveness of 5 invigoration treatments, i.e., seed without invigoration treatment, soaking in PEG 6000 -0.8 Mpa, soaking in PEG 6000 -1.2 Mpa, soaking in UFB water injected by environmental air, and soaking in UFB water injected by oxygen 99 %, with soaking time is 24 hours for each treatment. Seed agieng resulted three classes of seed viability, i.e. 62 % (initial seed), 83 % (seed agieng for 30 minutes) and 57 % (seed agieng for 60 minutes). In the condition of seed germination before treatment (DBA) 57 % and DBA 62%, invigoration treatments were significantly affected on seed germination capacity, but not significantly different in DBA 83 %. The soaking treatment of UFB injected by oxigen 99 % was able to improve the germination parameters (germination capacity, germination rate, and vigor index) on the sengon seeds with DBA 57 %. For seeds with DBA 62 %, the soaking treatment in UFB injected by environmental air was provided the best germination capacity, T50, and vigor index. The treatment of UFB injected by oxygen 99 % was more effective to improve the seed with very low viability and vigor (DBA 57 %). In general, improving of seed viability and vigor is more effective by using UFB than PEG 6000.



1976 ◽  
Vol 16 (82) ◽  
pp. 723 ◽  
Author(s):  
JG McIvor

The germination response of dehulled, scarified seeds to a range of constant and alternating temperatures, and to moisture stress was measured in seven Stylosanthes species. Rates of water uptake and loss were also measured. With constant temperatures, both total germination and germination rate were greatest at 25�C for all species except for S. hamata which germinated faster at 30�C. Both higher and lower temperatures slowed and depressed germination. Constant and alternating temperatures produced similar results except at high temperatures where germination was less with the alternating regime. Moisture stress greatly reduced germination of S. guyanensis cv. Cook, S. scabra and S. viscosa but had little effect on S. fruticosa, S. guyanensis CPI 40294 and S. subsericea. Initial rate of water uptake was greatest for S. hamata and S. subsericea but moisture content was similar for all species by 18 hours. There were no differences between species in rate of water loss from imbibed seeds.



2014 ◽  
Vol 20 (2) ◽  
pp. 191
Author(s):  
Sofía Basto ◽  
Claudia Ramírez

Tabebuia rosea germination capacity and rate have been examined under light and dark conditions. However, seeds responses to light quality, in particular to short and mid-wavelengths, are not well known. We hypothesized that short wavelengths would have a positive effect on rosea germination. The effects of short, mid and long-wavelengths on germination capacity, rate (germination rate index, germination rate R50, a devised index of germination rate R50´ and peak value), mean daily germination and germination value were evaluated. Light quality had little effect on germination capacity; it was reduced only in darkness. Seeds under short and mid-wavelengths germinated faster (germination rate) than under any other light treatments. We concluded that althoughlt T. rosea seeds respond to all light quality treatments, the short and mid-wavelengths are the cue for increasing germination speed. For synchronizing germination, short and mid-wavelengths transmitted by red cellophane paper can be used as a pre-germinative treatment for restoration and silvicultural purposes.



Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 671
Author(s):  
Tim L. Springer ◽  
Dolores W. Mornhinweg

The impacts of climate change may increase the duration and frequency of droughts, which would have deleterious effects on crop establishment. The objectives of this study were to determine the effects of moisture stress on seed germination and seedling growth of six winter barley (Hordeum vulgare) lines and discuss how the data are used to select plant materials for rapid germination. Twenty-five seeds of each line were germinated in water of potentials of −2.0, −1.6, −1.2, −0.8, −0.4, and 0 MPa for 4- and 7-days. The experimental design was a factorial arrangement of treatments (barley lines and water potential treatments) in a randomized block replicated four times and repeated twice. The 4- and 7-day percentage seed germination varied with line (p < 0.01), water potential treatment (p < 0.01), and line × treatment interactions (p < 0.01). The seed germination rate varied with water potential treatment (p < 0.01), and line × treatment interactions (p < 0.01). The data indicated that enough variation was present to effectively select and breed cultivars for improved germination at a negative water potential. Studying seed germination under moisture stress is the first step for developing an effected selection pressure for identifying plant materials with rapid seed germination.



Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 728
Author(s):  
Sandra Weller ◽  
Singarayer Florentine ◽  
Muhammad Mansoor Javaid ◽  
Amali Welgama ◽  
Aakansha Chadha ◽  
...  

Amaranthus retroflexus L. (Amaranthaceae), Redroot pigweed, is native to North America, but has become a weed of agriculture worldwide. Previous research into competition with food crops found it significantly reduces yields. Additionally, taxonomy, biomass allocation, physiological responses to light intensity, water stress, elevated CO2, and herbicide resistance have been investigated. To extend other research findings, we investigated growth and biomass yield in response to (i) soil moisture stress, and (ii) drought and elevated CO2. Additionally, we investigated seed germination rates following exposure to three elevated temperatures for two different time periods. Overall, moisture stress reduced plant height, stem diameter, and number of leaves. Elevated CO2 (700 ppm) appeared to reduce negative impacts of drought on biomass productivity. Heating seeds at 120 °C and above for either 180 or 300 s significantly reduced germination rate. These results inform an understanding of potential responses of A. retroflexus to future climate change and will be used to predict future occurrence of this weed. The finding that exposing seeds to high temperatures retards germination suggests fire could be used to prevent seed germination from soil seed banks, particularly in no-till situations, and therefore may be used to address infestations or prevent further spread of this weed.



2019 ◽  
Author(s):  
Chathurika Wijewardana ◽  
K. Raja Reddy ◽  
L. Jason Krutz ◽  
Wei Gao ◽  
Nacer Bellaloui

AbstractEffects of environmental stressors on the parent may be transmitted to the F1 generation of plants that support global food, oil, and energy production for humans and animals. This study was conducted to determine if the effects of drought stress on parental soybean plants are transmitted to the F1 generation. The germination and seedling vigor of F1 soybean whose maternal parents, Asgrow AG5332 and Progeny P5333RY, were exposed to soil moisture stress, that is, 100, 80, 60, 40, and 20% replacement of evapotranspiration (ET) during reproductive growth, were evaluated under controlled conditions. Pooled over cultivars, effects of soil moisture stress on the parents caused a reduction in the seed germination rate, maximum seed germination, and overall seedling performance in the F1 generation. The effect of soil moisture stress on the parent induced an irreversible change in the seed quality in the F1 generation and the effects on seed quality in the F1 generation were exasperated when exposed to increasing levels of drought stress. Results indicate that seed weight and storage reserve are key factors influencing germination traits and seedling growth. Our data confirm that the effects of drought stress on soybean are transferable, causing reduced germination, seedling vigor, and seed quality in the F1 generation.



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