Effects of temperature and seed coat treatments on germination of sweet pea

Tests on seeds of sweet pea (Lathyrus odoratus L.) were set up to examine responses to temperature during germination and to investigate the effects of mechanical and chemical treatments on the permeability of the seed coat to water.Optimum temperatures for germination occurred at about 21 °C, and higher temperatures resulted in the production of fewer seedlings. Although temperatures below c. 15 °C also reduced the numbers of seeds which germinated, even at 2 °C more than 50 % germinated within 60 days.Treatments with concentrated sulphuric acid or the mechanical removal of part of the seed coat by filing greatly increased permeability to water and under some conditions improved germination responses. Filing, followed by exposure to excess free water, reduced germination rates, possibly as a result of loss of solutes from the seed during imbibition.     

The germination of watercress (Rorippa nasturtium- aquaticum) seeds. I. The effects of age,storage, temperature,light and hormones on germination

The upper temperature limit for germination of watercress seeds was higher in the light than in the dark. Seeds became progressively less dormant following harvest, the upper temperature limit for germination in both light and dark becoming higher and the rate of germination increasing. Earlier-ripening seeds were more dormant than later-ripening ones. High humidity or a short period at high temperature during storage hastened dormancy loss. Germination at 20 °C in the dark could be induced by treatment with a combination of GA₄, GA₇ and benzyladenine. The promotion of germination by red light was nullified by immediate exposure to far-red light, indicating that the effect of light was mediated through phytochrome. The practical relevance of the results is discussed.     

Effect of stratification temperature,stratification period and seed coat on seed germination of peach cultivar ‘Sharbati’

Freshly harvested seeds of peach cultivar ‘Sharbati’ were found to be dormant and did not germinate at all. A specific low-temperature stratification treatment was required to overcome seed dormancy. 10° C stratification was found to be the best for breaking seed dormancy. Increased seed germination was recorded when the seeds were after-ripened without seed coats as compared to the seeds after-ripened with seed coats. There was no further increase in germination when seeds without seed coats were stratified beyond 60 days at 10° C, while a significant increase was recorded up to 75 days of stratification in the case of seeds with seed coats. Unstratified seed coats, soaked in water for 72 h, leached out a water-soluble inhibitor, which could suppress the germination of stratified peach seeds without seed coats. When this leachate was bioassayed by a cress-seed germination test, it showed the presence of an inhibitor at Rf 0.7-0.9. Hence, delayed germination of seeds with seed coats may be due to the presence of an inhibitor in seed coats.     

Fast germination of parsley seeds

The time from sowing to 50% radicle protrusion of parsley seeds (Petroselinum crispum L.) was about 1 month at 5°C and about 1 week at 15°C. Osmotic pre-treatment (“priming”) with a polyethylene glycol “6000” solution of ?12 bars water potential (302 g PEG “6000” per 1 kg distilled water) at 15°C for 3 weeks under aerobic conditions reduced this median radicle protrusion time at 15°C to 1 or 2 days for seeds which had been surface-dried after treatment, 2 or 3 days when they had been air-dried and stored for 1 week, and 3 or 4 days after 10 weeks' dry storage. The uniformity in germination time of an untreated seed population was usually good, and care was needed not to make this worse by “over-priming”. An appropriate pre-treatment could, however, slightly improve the uniformity. Germination percentage remained unaffected but the pre-treatment could appreciably improve the emergence percentage of seeds sown in wet soil. In a small-scale experiment out of doors, the weight of plants from certain seed treatments was significantly greater after 14 weeks' growth than that from untreated seeds.     

Physical dormancy in myrtle seed

The nature of dormancy in seeds of myrtle (Myrtus communis L.) was investigated. Scarification with cold acid or sand paper and soaking in water increased seed germination, whilst stratification, inserting the seeds in boiling water or hot acid treatment decreased the number of germinating seeds. The highest germination was obtained by treating the seeds with 100 % cold acid for 60 min or 80 % cold acid for 120 min. Hard seed coat was found to be the principal cause of poor seed germination.Scarified and non-scarified seeds were germinated for 2 weeks at 6 temperatures between 5 and 30° C, and 20° C was optimum.     

The Effect of Scion on Root.: II. Stem-Worked Apples.

Summary

The effects of seed coat removal and chilling on the germination of seeds of ten cultivars of ornamental peach (Prunus persica Batsch) were investigated. Seeds were rinsed in running tap water for 48 h in order to facilitate seed coat removal. Only a few non-chilled, intact seeds germinated (e.g., 6% of ‘Hito’ seeds). Seed coat removal and no chilling resulted in some seed germination in eight of the ten cultivars, ranging from 6% to 83%. Chilling intact seeds at 5°C for up to 10 weeks resulted in greater frequencies of germination (average = 85% germination) than seed coat removal before (average = 80%) or after chilling (average = 73%). There was a linear decrease in the germination percentage with an increase in abscisic acid (ABA) content for ‘Yaguchi’,‘Kanpaku’, and ‘Kikumomo’ seeds (R = –0.66; P <0.001). The most consistent decrease in total seed ABA content (average of 64%) occurred during the 48 h rinsing period. In ‘Kanpaku’, dry seeds had an intermediate ABA content (13 ng per seed); but, in the embryonic axes, this increased from 0.03 ng to 1.2 ng per seed with an increase in the duration of the chilling period. The lowest germination percentages were found in this cultivar. These results suggest that ABA synthesis in the embryonic axes during chilling may affect the varietal characteristic of seed dormancy, and that rinsing seeds for >48 h could remove sufficient ABA to allow seed germination with minimum chilling.     

A cold-treatment technique to improve the germination of vegetable seeds prior to fluid drilling

A simple method capable of treating large quantities of seeds prior to germination and fluid drilling is described. After an initial imbibition period at 20°C, seeds were placed at a temperature of 1°C; high enough for continued metabolism but too low for radical emergence. This treatment reduced the spread of time of germination, increased the percentage of seeds germinating and brought forward the mean germination time of seeds when transferred back to 20°C. Treated seeds emerged earlier and more uniformily than untreated seeds following pre-germination and fluid drilling in the field.     

Seed germination of seven pepper cultivars at constant or alternating high temperatures

Summary

Seeds of seven pepper (Capsicum annuum L.) cultivars (Anaheim TMR 23, California Wonder 300, Coronado, Jalapeno M, Ma Belle, Mercury, and Yolo Wonder B) were germinated at constant day and night temperatures of 25,30,35 and 40°C or at alternating temperatures of 40/25,40/30 and 40/35°C for 14 days. Germination percentages and rates were similar at 25 and 30°C. Largest differences in cultivar responses occurred at 35°C where germination percentages ranged from 24 to 96%, and rates, calculated as summation of the number of seeds germinated on a given day divided by day number, varied from 3 to 26 (theoretical maximum value of 100). At 40°C, germination percentages were less than 5% and rates were less than one for all cultivars. Cultivars with the most heat tolerance were ‘Mercury’ and ‘Yolo Wonder B’. At alternating temperatures, germination percentages and rates were higher than those at constant 40°C. The increases were greatest when the temperature was lowered by 15°C (40/25°C) and least when temperatures were lowered by 5°C (40/35°C). Tetrazolium tests showed that a large percentage of the ungerminated seed was still viable from the highest temperature. At lower temperatures, fewer ungerminated seeds were viable with no viable ungerminated seeds from the lowest temperature.     

Bioassay of germination inhibitors in extracts of Sapium sebiferum seeds of different provenance

Sapium sebiferum seeds from Huangshan, Wuhan, and Guiyang in China were studied to identify differences in their 1,000-seed mass and in concentrations of inhibitors of germination in the seed coat or endosperm extracted using methanol or acetone. Seed mass varied significantly in relation to origin, with the highest mass observed in seeds from Wuhan, followed by seeds from Huangshan and Guiyang. Extracts of seed coats or endosperm caused a marked inhibition of the germination index of cabbage seeds, but less inhibition of germination percentages. Endosperm extracts had a stronger inhibitory effect on cabbage seed germination than seed coat extracts. Inhibitor concentrations in whole seeds also varied with seed origin. Seeds from Wuhan exhibited a significantly higher level of inhibition than those from Guiyang or Huangshan, but no significant differences were observed between seeds from Guiyang and Huangshan. The efficacy of methanol or acetone extraction was also evaluated. For whole seeds from Huangshan and Guiyang, methanol was more effective than acetone, while acetone performed better than methanol for seeds from Wuhan.     

提高草莓种子离体培养发芽率的研究

该文以EMC、‘哈尼’‘丰香’‘北辉’等10份草莓为试材,研究了培养基质和种子处理对发芽的影响．以提高草莓种子的发芽率。结果表明：草莓种子处理、培养基质、品种等对发芽率、发芽速度有很大影响。种子整粒培养,栽培品种发芽困难,而野生品种发芽较容易,种子切开处理的,在不同的培养基质上,供试各品种的种子发芽率超过60％．最高达100％。培养基质以1,2MS＋3％蔗糖＋0．6％琼脂的为好,发芽率达90％以上。     

Electrolyte efflux into hot water as a test for predicting the germination and emergence of seeds

Summary

The leakage of electrolytes from ageing stocks of French bean, tomato and onion seeds into cold water was highly correlated (r = 0.776, P = 0.001) with electrolyte efflux into hot water (EEHW) at 58 ± 1°C for 0.5 or 1.0 h. The EEHW was highly correlated (r = 0.968–0.991, P = 0.001) with the duration of incubation. The EEHW was examined for its ability to predict the germination of seed stocks of each of these crops ranging in age from two to five months to four years. A high correlation of EEHW with germination percentage (r = 0.717, P = 0.001) and time to 50% emergence of those seeds which emerge (r = 0.589, P = 0.001), are evidence of the potential of this test to indicate seed quality. The ability of EEHW in predicting germination was comparable to electrolyte efflux into an 8 or 18 h bulk soak of cold water, and the EEHW test is quicker. It may therefore be a useful rapid method for predicting the germination and emergence of seeds.     

The effect of seed treatment on the germination and early growth of Euterpe edulis (family Palmae)

The germination rate of palm seeds can be improved by pre-treatment of the seed. Several methods proved effective for Euterpe edulis seed, but sulphuric acid immersion and hydrogen peroxide leaching treatments both decreased emergence of germinated seedlings and restricted plant growth up to 6 months after germination.The best overall results in germination and subsequent seedling development were from seed leached in water for 72 hours at 30°C. This treatment can be related to the natural conditions encountered by the seed in the highly leached soils of a tropical rain forest.     

Temperature requirements for the germination of olive seeds (Olea europaea L.)

Summary

Olive seeds cv Chondrolia Chalkidikis were subjected to temperatures of 5°, 10°, 15°, 20°, 25° and 30°C for one, two or three months, and were then transferred to 20°C. Exposure to 10° and 15° for one month or more caused higher emergence percentages compared to that at a constant 20°C. The highest germination rate was observed when seeds subjected to 10°C for one month were then transferred to 20°C. Seeds at 5°, 25° and 30°C did not germinate while being held to these temperatures; even when transferred to 20°C the percentage and rate of emergence were lower than those of seeds held at constant 20°C. In another experiment, in which seeds were subjected to 10°C for 0, 2, 4, 6 and 8 weeks before being transferred to 20°C, it was found that four weeks exposure to 10°C was near optimal. Emergence percentages of seeds at constant 10°C or at diurnally alternating temperatures of 10° for 16 h/20° for 8 h were high and equal (92%), but emergence in the latter treatment was slower. Alternating 10° with 25°C resulted in a 95% reduction of the emergence percentage. Transferring seeds immediately after chilling at 10°C for three or four weeks to 25°C, partially reversed the effect of the low temperature. However, the chilling effect could not be reversed when the seeds were subjected to 10°C for five weeks.     

Effect of stratification-temperature,chemical treatments and seed coat on the growth of peach seedlings cultivar ‘Sharbati’

In order to obtain normal seedlings of peach cultivar ‘Sharbati’ before the commencement of winter, treatments with GA₃, thiourea and kinetin were given to seeds before stratification at 7°C, 10°C or 24°C. The seedlings raised from the treated seeds and after-ripened at 24°C were dwarf. The seedling growth was increased when the treated seeds were stratified at 10°C or 7°C and the stratification period was prolonged from 15 days to 75 days. 10°C stratification-temperature was better than 7°C. The seedling growth was improved when the seed coat was removed before the treatments. With respect to both seed types, 1000 mg/l GA₃ produced the tallest seedlings at all the after-ripening temperatures and during each stratification period. The next best treatment was 100 mg/l kinetin.     

Low temperature and gibberellic acid stimulation of germination in Sambucus caerulea Raf

Sambucus caerulea (elder) seeds did not germinate after 4°C cool treatments for up to 30 days, when monitored for a further 30 days at 21°C. When seeds were soaked for 24 h in gibberellic acid (GA₃) prior to and during cold treatment, germination percentage depended on GA₃ concentration and duration of cold treatment. The highest germination percentage was 55 (1000 mg l⁻¹ GA₃ for 30 days at 4°C). When seeds were treated with ethephon at 0, 100 or 1000 mg l⁻¹, no germination was recorded after a subsequent 30-day 4°C treatment. Ethephon added to GA₃ gave a strong interaction, leading to further promotion in germination. Optimal germination was obtained after 1000 mg l⁻¹ GA₃ and 100 mg l⁻¹ ethephon for 30 days at 4°C (69%).The addition of ethanol, acetone, dimethyl sulfoxide or polyethylene glycol to the GA₃ soak as infusion agents either reduced or did not change the germination percentage.     

Partial vacuum extends the longevity of primed bitter gourd seeds by enhancing their anti-oxidative activities during storage

This study evaluates the effects of partial vacuum storage on longevity and anti-oxidative responses of primed bitter gourd (Momordica charantia L.) seeds. Priming was achieved by mixing the seeds with moist vermiculite 25 °C for 36 h, followed by air-drying to the original moisture level. Primed seeds were vacuum-packed and stored at 25 °C for up to 12 months. Priming improved seed germination, reduced lipid peroxidation and enhanced anti-oxidative activity prior to storage. However, primed seeds accumulated more total peroxide than non-primed control after 12 months non-vacuum storage, and this led to a marked decrease in seed longevity. Increased total peroxide levels were associated with decreased percentage of 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical inhibition. Partial vacuum storage proved useful in extending the longevity of primed seeds for up to 12 months. Improved longevity was related to enhanced anti-oxidative activity that minimized the accumulation of total peroxide during long-term storage.     

孟士德薰衣草种子萌芽生物学特性研究

以孟士德薰衣草为试验材料,研究温度、光照以及赤霉素等外界条件对孟士德薰衣草种子萌发的影响,以期找到提高孟士德薰衣草种子萌芽率的有效方法,为孟士德薰衣草的播种繁殖及育种工作提供科学的理论依据。结果表明:(1)孟士德薰衣草的种子黑褐色,表皮光滑,种皮坚硬角质化,外包蜡质,种子千粒质量(0.947±0.045)g;(2)200 mg/L赤霉素浸泡处理6 h孟士德薰衣草种子萌芽率最高,达到94.6%;(3)15℃黑暗环境下孟士德薰衣草种子萌芽率最高,达到95.2%,20℃次之,为94.6%,但相比15℃幼苗长势更好;(4)光照10 h处理有利于孟士德薰衣草种子萌芽,萌芽率为94.6%,且幼苗长势最好;(5)采用不同浓度GA3对孟士德薰衣草种子进行处理,以200 mg/L的GA3处理种子萌芽效果最佳,萌芽率达到94.0%。     

Seed viability,seed deterioration and seed quality improvements in stored onion seeds: a review

Nowadays, the area under onion production through seeds is increasing in India and especially in Tamil Nadu. Onion (Allium cepa L.) seeds are naturally less viable and more hygroscopic than seeds of most common vegetables. Moreover, in most areas, storage of onion seeds in improper or adverse conditions results in a serious problem called seed deterioration, which is characterised by loss of viability, loss of vigour, and loss of seed quality. Therefore, there is a significant demand for quality onion seeds in the seed chain. Hence, here, the literature pertaining to onion seed viability, seed deterioration and seed quality improvements have been reviewed. Scrutiny of the literature reveals that storage of onion seeds at low seed moisture content, low storage temperature and low relative humidity and exploitation of seed invigoration treatments like hydration-dehydration would significantly help in delaying the seed deteriorative processes and, thereby, increasing the viability and longevity of seeds during storage. Importantly, it can be concluded that germinability and vigour of onion seeds can be maintained for more than one year by reducing the seed moisture content to 6 ± 1% and storing them in moisture impervious containers at 4 -15°C and 40 -60% relative humidity (RH).     

Effect of seed coat on peach seed germination

Various treatments to remove the seed coat surgically revealed its role in preventing germination of non-stratified peach seed. The peach embryo from a non-chilled seed is not dormant, as it germinates readily when the seed coat is completely removed. The peach seed coat provides a physical impediment — commonly referred to as mechanical resistance to germination. Incision through the seed coat around the seed at the cotyledonary gap allowed germination even though the seed coat remained in contact with the embryo. No role for inhibitors extracted from the seed coat could be elucidated.     

Effects of Pre-Stratification Storage Conditions on Black Walnut Seed Post-Stratification Germination Capacity

The objective of this work was to quantify changes in the germination capacity of Juglans nigra seeds following storage and then artificial stratification. Seeds were stored at 5 and –20 °C under 5% and 14% internal moisture content (IMC) for 0, 8, 10, and 12 months under conditions with oxygen or under vacuum. Germination percentage (GP) was affected by storage temperature, IMC, and storage period. Seeds stored with 5% IMC succeeded in germinating regardless of the temperature. Seeds stored with 14% IMC did not germinate (–20 °C) or germinated during storage (5 °C). The GP was reduced with the time of storage in seeds at –20 °C and 5% IMC and this effect was avoided in storage under vacuum. In conclusion, the germination capacity of black walnut seeds did not change for up to 12 months at low above-zero temperature and low IMC (5 °C, 5% IMC), being the most cost-effective alternative for long-term storage of black walnut seeds in commercial nurseries. Vacuum storage avoided the decrease of around 50% in average germination capacity of seeds stored for a year at –20 °C.