Average Germination Percentage Research Articles

Effect of Simulated Acid Rain on Seed Germination of Three Solanaceous Vegetables

Tomato, brinjaul and capsicum seeds were treated with simulated acid rain at pH 2.0, 3.0, 4.0, 5.0 and 6.5 (as ck)levels in order to research the effects of acid rain on their germination. According to the four germination indexes of germination percentage, germination energy, germination index and average germination percentage per day, the results showed the germination of tomato seeds was slightly inhibited at pH 2.0～3.0; however, brinjaul seeds was greatly inhibited, especially at pH 2.0 and they almost can’t germinate; capsicum seeds were not affected by the variational pH values, and germinated well. All four germination indexes reduced with pH decreased. Under the acid rain stress from pH 2.0 to pH 5.0, the amplitude difference of water absorbance value was capsicum (13.75) tomato (19.91) brinjaul (20.58), under the same acid rain stress condition, the inhibition index of shoot length, decreasing amplitude difference of protein content and amplitude difference of MDA content was capsicum tomato brinjaul. The results indicated that the resistance ability to acid rain was capsicum tomato brinjaul.

Cardinal temperatures for germination of Kochia scoparia (L.)

In order to examine seed germination responses of kochia ( Kochia scoparia L. Schrad) to temperature regimes, an experiment was performed in a completely randomized design with two replications. The trial was conducted at 8, and 5 °C intervals from 10 to 40 °C. From 8 to 35 °C, average germination percentage was 85%, but when temperature increased to 40 °C, germination percentage decreased to 31%. At 25 °C, 50% germination was achieved within the first 24 h, but when temperature increased or decreased from this level, germination was slower. On the basis of these results, kochia can adjust its germination over a wide range of temperatures, from 3.5 °C ( T b) to 50 °C ( T max), with an optimum germination temperature of 24 °C. This extended temperature range for germination and the ability to germinate rapidly suggest the high potential of kochia to establish in most areas of Iran as a new forage crop.

Armazenamento e germinação de sementes de Tabebuia aurea (manso) Benth. & Hook. f. ex. S. Moore

As sementes foram acondicionadas em sacos de papel, de algodão e plástico de natureza permeável, em ambiente frio e seco (15ºC e 40% de UR) por quatro meses. Inicialmente, testou-se a influência da presença e ausência contínua de luz branca e fotoperíodo de 12 h, a fim de determinar o fotoblastismo das sementes, na temperatura de 25ºC. Verificou-se a influência das temperaturas constantes de 10, 15, 20, 25, 30, 35 e 40ºC na germinação e determinou-se as temperaturas cardeais (mínima, ótima e máxima). Testou-se a viabilidade das sementes aos 60, 90 e 120 dias de armazenamento, empregando-se teste de germinação, e a velocidade de embebição aos 30, 60 e 90 dias, utilizando-se amostras provenientes de cada tipo de embalagem. As embalagens utilizadas no armazenamento não afetaram significativamente as variáveis estudadas. A espécie em estudo pode ser classificada como fotoblástica neutra à 25ºC, com percentagem média de germinação alta, variando de 88 a 98%. A temperatura ótima de germinação foi de 35ºC, a mínima de 20ºC e a máxima de 40ºC, na ausência de luz. As embalagens utilizadas no armazenamento mantiveram a viabilidade das sementes por até 120 dias, com altos percentuais de germinação, variando de 88 a 97%. As sementes apresentaram velocidade de embebição rápida atingindo 100% a partir das quatro horas de embebição.

Germination Percentage and Germination Speed of European Larch (Larix decidua Mill.) Seed After Prolonged Storage

Abstract Thirty European larch seedlots stored in plastic, screw-capped containers at 4°C for 3 to 24 yr were tested for their viability. The average germination percentage was 26.7% per seedlot. Fifty percent of all germinating seeds germinated by the 20th day after sowing and 90% had germinated by the 26th day. Correlation analysis indicated there was a significant negative association between years in storage and germination percentage and a significant positive association between years of storage and the number of days required to reach 15% germination. Although one seedlot germinated no seeds after 10 yr in storage, 21 of 30 seedlots, ranging from 3 to 24 yr in storage, maintained a minimum germination percentage of 20%.

Collection and storage of pollen from Salix (Salicaceae)

Genetic improvement of willows through traditional breeding can be facilitated by pollen collection and storage so that female flower receptivity need not be synchronized with pollen shed for breeding. Two experiments were completed to test the effectiveness of various organic solvents for willow pollen collection. In the first experiment, seven pollen collection treatments and an untreated control were tested with two willow clones. The other experiment tested three treatments that showed promise in the initial experiment and an untreated control with eight willow clones. Toluene and carbon tetrachloride were effective for pollen extraction, with average pollen germination percentages that were >15%, but both chemicals reduced pollen viability by 10-20% compared with an untreated control based on in vitro germination tests. Pollen extracted with carbon tetrachloride or toluene was successfully used in controlled pollination, and >100 new families were produced with this technique. Pollen viability remained high after 18 mo of storage at -20°C. Based on our results, toluene is the preferred solvent for future willow pollen extractions because it is as effective as carbon tetrachloride, is not a known carcinogen, and is less expensive.

Germination responses of temperate Carex-species to diurnally fluctuating temperatures – a comparative study

Summary Effects of diurnal temperature fluctuations on the germination of 34 temperate Carex -species were investigated. Experiments were conducted on recently matured seeds at 22°C mean temperature with fluctuation amplitudes of 0° – 16°C, and at 22/10°C (15°C mean temperature) in light and darkness before and after a cold-wet stratification. At 22°C mean temperature, seed germination increased in almost all investigated species with increasing temperature amplitudes, in both light and darkness. The average germination percentage across all species was 29.4% in light and 5.1 % in darkness. The averaged amplitude required to reach 50% of maximum germination was 9.8°C. Species with little sensitivity to temperature fluctuation in light showed a clear sensitivity in darkness. The germination percentage was 4.0% for species with seed weights >0.9 mg and 23% for species with seed weights Carex species, thus suggesting that their germination behaviour was determined not only by habitat conditions.

Manipulating dormancy of capeweed (Arctotheca calendulaL.) seed

AbstractCapeweed (Arctotheca calendula) seeds were found to be dormant at harvest. Effects of duration and temperature of storage under ‘laboratory’ and ‘natural’ conditions, growth regulators, stratification and age of seeds, were studied on the germination of dormant seeds. Three factors imposed on seeds were found to promote germination of capeweed: (i) allowing seed to age, either in storage, buried in soil or during stratification (germination of 18-month-old seeds was up to 60% higher than that of fresh seeds); (ii) the presence of light (the average germination percentage of seeds exposed to light during storage was 3.2-fold greater than that of seed stored in the dark); and (iii) the application of growth regulators, particularly gibberellic acid, enhanced by scarification (GA3and ethephon promoted germination by up to 58% when applied to scarified seeds). Other factors, e.g. temperature and depth of storage, influenced germination but were less critical to its success. These results provide a preliminary assessment of the importance of these factors in controlling dormancy in seeds of capeweed.

Pollen–pollen interactions in Betula pendula in vitro

Direct pollen interactions, as well as interactions mediated by a recipient, can have a remarkable influence on pollen fertilization ability. Under conditions of pollen competition it could be advantageous if pollen grains interfered with the germination of other pollen. The aim of this study was to find out if there are direct negative or positive pollen–pollen interactions between pollen grains from genetically slightly different donors. The in vitro germinability of the pollen from several Betula pendula Roth clones was investigated. The pollen interactions between the clones were examined pairwise by using equal pollen mixtures. In three of the eight cases the germination percentage of the pollen mixture was significantly higher than the average germination percentage of the separate clones that formed the mixture, which indicates some type of interaction between the pollen populations. We found only positive interactions between the pollen of clones. This study also documented density‐dependent germination of pollen grains in vitro (=pollen population effect). Adding an aqueous pollen extract to the incubation medium increased the germination percentages of poorly germinating pollen and small pollen populations. Germination‐stimulating effects were found to exist both with fresh and dead pollen. Such direct pollen–pollen interactions could be explained by specific water‐soluble substances diffusing from pollen grains.

GERMINAÇÃO, CRESCIMETO INICIAL E NODULAÇÃO EM VIVEIRO DE SABOARANA (Swartzia laevicarpa AMSHOFF)

Swartzia laevicarpaAmshoff ("Saboarana") é uma leguminosa cuja capacidade de se associar simbioticamente a bactérias fixadoras de nitrogênio foi recentemente descoberta. A madeira pode ser explorada economicamente para: marcenaria de luxo, carpintaria e construção em geral, além disso é uma espécie bastante frequente em rios de água preta, e tem boa disponibilidade de sementes. Características da germinação natural de suas sementes e do crescimento inicial e nodulação em 5 substratos no viveiro foram pesquisadas. As sementes têm polimorfismo acentuado, poliembrionia e apresentam alta porcentagem (94%) de germinação hipogeal num período de 18-43 dias após a semeadura (realizado 8 dias após a coleta). Todos os parâmetros de crescimento avaliados como: altura da planta, diâmetro do colo e peso da parte aérea fresca e seca foram maiores nos substratos de baixa fertilidade - Areia com adubo inoculada com rizóbio, convencional (mistura argila e areia 3:2) e terriço de floresta sem adubo. A nodulação foi maior no substrato convencional. Nos substratos de maior fertilidade - solo de várzea e terriço de floresta com adubo - o crescimento e a nodulação foram significativamentes menores. Estes resultados indicam que a "Saboarana" é uma espécie adaptada a condições de baixa fertilidade.

Quality of Durum Seed Planted in North Dakota

Surveys have periodically evaluated the quality of wheat seed being planted by commercial farmers but, little has been published on the field of performance of survey samples. Durum wheat (Triticum durum L.) samples were accumulated from eight North Dakota counties in 2 yr to: (i) evaluate the quality of seed planted by North Dakota commercial farmers, (ii) test the field performance of sampled seed, and (iii) evaluate the economic impact associated with the planting of certified quality seed. Durum wheat samples were accumulated during planting from 152 and 120 farmer drills in 1987 and 1988, respectively. Lab analyses were conducted for germination and purity. Field trials were conducted in subsequent years at Casselton and Prosper, ND, on Bearden silty clay (fine silty, frigid Aeric Calciaquoll) and Perella fine silty (fine-silty, mixed, frigid Typic Haplaquoll) soils, respectively. Overall quality of the seed samples was extremely variable. Average germination percentage was 84.5%, which was below the minimum certified seed standard and noncertified were different from certified seed samples. Mean values for other crop and weed seeds exceeded the maximum level for certified seed, but did not differ significantly from certified seed samples. Plant stand had a significant effect on grain yield, particularly when the environment produced high yield levels. Averaged over the 2 yr, certified seed yield was 7.1% higher than noncertified. These results indicated that producers in North Dakota could have increased their 1988 gross return from durum wheat production by more than $6.0 million with exclusive use of certified quality seed. Research Question Durum wheat is a major crop in North Dakota. Farmers plant durum seed derived from widely varied sources. The primary objective of this study was to accumulate samples from farmers' drills to compare the quality of seed being planted and evaluate the field performance. Literature Summary Numerous studies have related the effect of seed viability and seed vigor to field performance. Seed size or test weight is another component of seed quality that has been studied extensively. Generally large seed with good viability has the best performance. Surveys have been conducted in several states to evaluate the quality of seed being planted. Frequently, these surveys have been used to bring attention to a continuing need for improved purity of seed being sold in commercial channels. No studies, however, have been published to associate the impact of seed quality on economic potential for durum wheat. Study Description Durum seed sources used by farmers were sampled at planting time in eight North Dakota counties during 1987 and 1988. Accumulated samples were analyzed for germination percentage and purity variables in the lab. Replicated field trials were conducted at two locations in the year following sampling to determine emergence, grain yield, and test weight performance. Applied Questions What is the quality of durum seed currently being planted? Overall quality of the seed samples from 274 drills was extremely variable. Germination tests averaged 84.5%, which is below the minimum standard for certified seed. Mean values for purity were excessive for other crops and weed seeds exceeded the maximum level for certified seed, but did not differ significantly from certified seed samples. Field emergence ranged from 26 to 100%. Stand had a significant effect on grain yield, particularly when the environment favored high yield potential (Fig. 1). How does certified seed compare with noncertified in yield performance? The survey indicated that 13.2% of the durum acreage was planted with certified seed. Grain yield from certified seed averaged 7.1070 higher than from noncertified seed. These data indicate the statewide average durum yield and economic return could be increased simply through the exclusive use of seed equivalent to certified seed. Cost inputs associated with additional weed control and possible reduced crop value due to seed impurity would add to the economic value of high quality seed. Figure 1Open in figure viewerPowerPoint Effect of plant stand on durum grain yield averaged over two locations.

Changes in Soybean Seed Quality from High Temperature during Seed Fill and Maturation1

Soybean [Glycine max (L.) Merr.] seed production is often located in areas where high temperatures prevail during part or all of the seed‐filling and maturation phases of seed growth, which may reduce the subsequent quality of harvested seed. Research was undertaken in 1981 and 1982 to study the effect of various lengths of high temperature during seed filling and maturation on soybean seed quality. Potted soybean (cv. Century) plants were transferred from the field to two growth chambers approximately 5 days before growth stage R5. Plants were exposed to a day/night temperature of 32/28°C (high) for 10, 20, 30, and 40 days after flowering and to a 27/22°C (low) temperature during the rest of the seed‐development and maturation period. The seeds were divided into two groups P1 (from main‐stem pods) and P2 (from branch and top main‐stem pods). Exposure to increasing periods of high temperature during seed fill resulted in a linear decline in seed germination, vigor, and physical quality. The average germination percentages were 84 and 50% when the low and high temperatures were extended to pod maturity, respectively. The percentages of small, etched, discolored, and wrinkled seed were 0.1, 3.6, 2.3, and 0.2%, respectively, under constant low temperature, but the percentages increased to 2.7, 20.1, 26.2, and 2.8% under constant high temperature. The high temperature directly influenced germination, vigor, and physical quality even when applied during the first 10 days of the seed‐filling period. Phomopsis sp. (pod and stem blight fungus) seed decay averaged less than 4% and did not account for the reductions observed in germination or vigor. Seedling axes dry weight and final average seed weight were the only measurements that showed any consistent difference between P1 and P2 seeds, with P1 seeds being more vigorous and having greater average seed weight than P2 seeds. The interaction of temperature treatments and seed position on the plant was not significant for any seed and seedling measurements. Factors that shorten the length of high‐temperature exposure during seed filling and maturation should reduce seed damage.

Seed Vigor Measurements for Predicting Field Establishment of Pearl Millet

Seed vigor is one of the many problems that limit grain millet production because it affects field establishment and, thus, yields. The purpose of this study was to measure vigor in grain millet seeds and select from common vigor tests, the one most appropriate for pearl millet. We used 20 varieties in 1977 and 30 in 1978 to investigate the ability of standard germination, electrical conductivity of soaked seeds, NH4Cl and NaOH stress tests, artificial aging, and soil cold testing to predict field establishment. Field establishment counts were made on three planting dates in 1977 and four in 1978 at Manhattan and two planting dates at St. John in 1978. Germination percentages from the stress tests were lower because stress killed seeds of low vigor while vigorous seeds remained relatively unaffected. Criteria used to evaluate laboratory vigor tests included correlation with field establishment and ability to rank millet varieties according to field performance. NaOH, NH4C1, accelerated aging, and standard germination treatments were significantly (0.01 level) similar in ranking seed lots according to vigor. Standard germination results are commonly used to predict field establishment, but standard germination often overestimates field establishment (Vanderlip et al., 1973). Barnes (1960) and Vanderlip et al. (1973) concluded that field establishment of a seed lot should be predicted from germination percentages from a stress test because weaker or nonvigorous seeds would be killed and, as in the field, only vigorous seeds would survive. Seed and seedling vigor particularly affect field establishment of proper plant populations. Algarswamy et al. (1977) indicated that genetic differences Contribution 79-241-J, Agron. Dep., Kansas Agric. Exp. Stn., Manhattan, KS 66506. Part of a thesis submitted by the senior author in partial fulfillment of requirements of the M.S. degree. Supported by funds from the Ford Foundation and USAID, Washington, D.C. Contracts No. AID/ta-c-1458 and AID/DSAN-G-0149, Title XII, INTSORMIL. 2 Present address: Kilombero Sugar Co., Ltd., Kidatu, Tanzania. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 06:23:13 UTC All use subject to http://about.jstor.org/terms 58 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE Table 1. Average germination percentages from indicated laboratory vigor tests. Laboratory test 1977 1978 Standard germination 79.3 85.8 NH4Cl treatment 71.9 81.2 NaOH treatment 51.9 58.7 Accelerated aging 30.8 65.5 Cold test 17.1 Vigor analyzer 30 min soaking 63.8* Overnight soaking 85.4* * Percentage identified as vigorous by the analyzer, not percentage germinated. in seedling vigor among pearl millet [Pennisetum americanum (L.) K. Schum] genotypes could be distinguished by visually scoring the plants under field conditions. Mahadevappa (1968), who found no differences among pearl millet parents and hybrids in germination, reported significant differences in rates of respiration, seedling height, fresh weight, root-to-shoot ratio, total root length, and leaf area. Our research measured vigor in grain pearl millet varieties and evaluated these varieties with vigor tests used on other crops. MATERIALS AND METHODS Laboratory tests Laboratory tests in 1977 were: standard germination (Anonymous, 1954), soaking seeds in 2% ammonium chloride solution for 2 hours (Helmer et al., 1962), artificially aging seeds at 400C and 84% relative humidity for 10 days (Abdullahi and Vanderlip, 1972), soaking seeds in 5% sodium hydroxide solution for 2 minutes (Barnes, 1960), and cold testing (Abdullahi, 1968). Seeds were rinsed in water after NH4C1 and NaOH treatments before germination. Twenty varieties with 50 seeds per seed lot replicated 4 times were used in both field and laboratory tests. In 1978 a different set of 30 seed lots was used and seed number per treatment was increased to 100. The same tests and procedures were used except electrical conductivity (Vigor Analyzer)3 of seeds soaked either for 30 minutes or overnight replaced the cold test. Field experiments At Manhattan in 1977, a split plot design was used with 3 planting dates 3 Equipment provided by AgroSciences, Inc., Ann Arbor, Mich. Use of product names does not imply endorsement over similar products not named. This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 06:23:13 UTC All use subject to http://about.jstor.org/terms VOLUME 89, NUMBERS 1-2 59 Table 2. Simple correlations between pearl millet field establishment and laboratory vigor tests. Laboratory vigor tests Location, year, and date

Germination Responses of Opuntia spp. to Temperature, Scarification, and Other Seed Treatments

Scarification in sulfuric acid consistently increased germination of Opuntia edwardsii sp. nov, O. discata Griffiths, and O. lindheimeri Engelm. ♯ OPULI seeds over that of untreated seeds. Optimum constant temperatures for germination were generally 25 to 35 C and germination was not enhanced by alternating temperatures. There was a trend for increased germination following leaching in water for 12 h which suggested the presence of chemical germination inhibitors. Seeds passed through the digestive tracts of cattle exhibited average germination percentages that were 1.5 times greater than seeds removed from ripe fruits.

Estudos silviculturais de uma população natural de Copaifera multijuga Hayne - Leguminosae, na Amazônia Central. 1 - Germinação

Resumo O autor estuda a germinação da Copaíba (Copaifera multijuga Hayne), como trabalho complementar aos estudos que o mesmo desenvolve na Reserva Ducke, sobre a produção de óleo-resina de uma população natural. Foram estudadas as sementes coletadas de 16 árvores selecionadas, com as quais foram realizados testes de pureza, vitalidade e de germinação. O autor verificou que a espécie apresenta alta percentagem média de germinação com 87,5%, com o início da germinação ocorrendo 14 dias após a semeadura e o período total de germinação de 35 dias, em média.

Effect of freezing and freeze-drying on the viability and storage of Lilium longiflorum L. and Zea mays L. pollen

The freeze-preservation of pollen is dependent on the interaction of several factors such as freezing rate, thawing rate, freeze-drying temperature and duration, storage temperature and environment and rehydration rates. Changes in any of these variables affects the others directly or indirectly. Rapid freezing of pollen at rates of approximately 200 °C/min maintains the highest degree of viable pollen in combination with rapid thawing rates of 218 °C/min. Rapid cooling and slow rewarming resulted in a substantial loss of pollen viability. This might indicate that intracellular ice crystals formed during rapid cooling perhaps grow into larger ice masses during slow rewarming or storage at temperatures above −50 °C. The germinability of pollen freeze-dried at temperatures below −50 °C was also prolonged over that of the controls. Germination values for unfrozen pollen stored for 30 days at 0–5 °C averaged 50% for lily and 20% for corn. Freeze-dried pollen stored for 30 days at the same temperature yielded considerably higher viability percentages for both lily and corn pollen. Drying time is an important factor, perhaps indicating that residual moisture is critical. Freeze-dried pollen can be stored at higher temperatures than frozen and control pollen. Freeze-dried material stored for five months at 0–5 °C, upon slow rehydration yielded intact grains which has average germination percentages of 25 for lily and 15 for corn. The same pollen upon rapid rehydration showed rupturing of 20–40% of the cells and practically no germination.