Effect of soil moisture during stratification on dormancy release in seeds of five common weed species

Although the effects of cold stratification on the release of physiological dormancy in seeds have been studied extensively, knowledge of the role of soil moisture content on seed dormancy release during cold stratification is limited. Our study determined seed dormancy characteristics and the effect of soil moisture content on seed dormancy breakage during cold stratification in the five common weed species Amaranthus retroflexus, Chenopodium album, Chenopodium hybridum, Plantago lanceolata and Setaria glauca. Seeds of all five species were dormant at the time of harvest and their germination response to light and temperature varied. Soil moisture content had a significant effect on seed dormancy release of all species except P. lanceolata. Germination percentage of A. retroflexus, C. album, C. hybridum increased and then decreased as soil moisture content increased, regardless of germination test temperature. The optimal soil moisture content and seed moisture content for dormancy breakage of A. retroflexus, C. album, C. hybridum were 8%, 12%, 8% and 22.0%, 37.7%, 25.7% respectively. Dry storage (after‐ripening) significantly increased germination of S. glauca. Moreover, increasing soil moisture content first slowed and then increased dormancy breakage in S. glauca. These results suggest that data on soil moisture content should be incorporated into models that predict weed seed dormancy breakage and timing of seedling emergence as well as those for weed management.     

Determination of Festuca filiformis seedbank characteristics,seedling emergence and herbicide susceptibility to aid management in lowbush blueberry (Vaccinium angustifolium)

Festuca filiformis is a common perennial grass in lowbush blueberry fields, but little is known about the general biology, seedbank characteristics, seedling recruitment or susceptibility of seedlings to currently registered herbicides. The objectives of this research were to determine (i) the presence of F. filiformis seedbanks in lowbush blueberry fields, (ii) whether F. filiformis seedbanks accumulate near the soil surface in lowbush blueberry fields, (iii) the dormancy status of fresh F. filiformis seeds, (iv) the temporal patterns of seedling recruitment in established F. filiformis populations, (v) whether F. filiformis has a vernalisation requirement for flowering in lowbush blueberry and (vi) susceptibility of F. filiformis seedlings to various herbicides currently registered in lowbush blueberry. Festuca filiformis formed a seedbank in lowbush blueberry fields, with an average of 1660 ± 272–5680 ± 1409 seedlings m^?2 emerging from soil cores collected from two infested fields. Most seeds were located at the soil surface, providing opportunities for seedbank management through predation or burning. Fresh seeds lacked dormancy and readily germinated, although germination was reduced by dark conditions. New seedlings emerged in spring and autumn and required vernalisation to flower. Seedlings were susceptible to several currently registered herbicides in lowbush blueberry, although mortality rates were highest in plants treated with glufosinate, flumioxazin, glufosinate + flumioxazin and terbacil. Growers should avoid movement of seeds on machinery, and additional research should be conducted to determine the effects of registered herbicides on F. filiformis seedling recruitment under field conditions in lowbush blueberry.     

不同处理对解除小麦种子休眠效果的研究

以发芽势、发芽率作指标，采用ＧｒｉｆｆｉｎｇⅡ设计，研究了４因素共１１种组合（包括对照）对解除两种不同上色的小麦种子休眠的效果。结果表明：１μｍｏｌ／Ｌ的ＧＡ３（赤霉素ＧＡ３）效果较好，在所有组合中，以５０℃的高温处理２４ｈ后用１μｍｏｌ／Ｌ的ＧＡ３浸种１２ｈ最好，能显著提高种子的发芽势和发芽率，在小麦夏繁中有一定应用价值。     

Role of Testa, Cotyledons and Embryonic Axis in Seed Dormancy of Groundnut (Arachis hypogaea L.)

Experiments were carried out during winter–summer (January–June) season to understand the role of seed testa, cotyledons and embryonic axis in imparting dormancy of some groundnut cultivars belonging to different habit groups. Crop was harvested at four maturity stages; 90, 100, 110 and 121 days after emergence (DAE). After drying the pods in shade for 2 days, the germination of seeds with (GST) and without (GSW) testa in rolled germination towels and seeds, and embryonic axes (GEM) in culture media from individual plants of a cultivar was studied. Seed testa played an important role in imparting dormancy followed by the cotyledons, and embryonic axis. However, the nature of dormancy of embryonic axis appeared to be different from that of the testa and cotyledons. Results suggested that the dormancy in groundnut is regulated mainly by testa (a maternal tissue) in the Spanish type, but by cotyledons, and embryonic axis (both zygotic tissue) as well as testa in Virginia types. Thus the genetic control of seed dormancy in groundnut appears to be quantitative in nature.     

Identification of differentially expressed genes associated with bud dormancy release in tree peony （Paeonia suffruticosa） by suppression subtractive hybridization

A subtractive cDNA library was developed to study genes associated with bud dormancy release in tree peonies.In order to identify genes that are highly expressed in buds released from dormancy,588 clones were examined by differential screening.Of these,185 clones were selected to be sequenced.A total of 37 unique sequences were obtained of which only 31 sequences have matches in the NCBI database or the Arabidopsis thaliana protein database.Semi-quantitative RT-PCR was used to confirm further the expression...     

激素和热水处理对姜荷花种子发芽的影响

【目的】以姜荷花杂交种子为研究对象，通过不同浸种处理试验，打破姜荷花种子休眠，缩短姜荷花育种周期。【方法】利用激素、热水组合处理的方式，设置不同的浓度和浸种时间，以清水为对照，在 28 ℃条件下采用培养皿滤纸法催芽 60 d，统计发芽势和发芽率。【结果】与对照相比，外源激素和热水处理均能有效打破姜荷花种子休眠，使其提前 1 个月开始发芽。外源激素浸种试验中，400 mg/L GA3 浸种处理效果最好，发芽势和发芽率分别为 29.3%、50.7%；80 ℃热水浸种 5 min 效果最好，发芽势和发芽率分别为 10.3%、17%，但部分种子出现烫死现象；在组合浸种处理试验中，60 ℃热水浸种 10 min + 400 mg/L GA3 浸种 24 h 为最佳的处理组合，发芽势为 40.7%，播种 60 d 发芽率达到 64.3%。【结论】激素和热水组合处理对姜荷花种子解除休眠的效果显著优于其他处理，浸种后种子发芽提前，出苗更加整齐，适合育种实践中推广应用。     

野老鹳草Geranium carolinianum种子的萌发条件

为明确野老鹳草Geranium carolinianum种子的休眠特性及萌发适宜的环境条件，采用培养皿法和盆钵法研究野老鹳草种子萌发和出苗适宜的条件，记录种子萌发数，计算种子萌发率、平均萌发时间及萌发指数。结果显示，野老鹳草具有较长的休眠期，新采集的野老鹳草种子在室温干储210 d后可以解除休眠；在10~25℃的恒温条件下种子萌发率均在93.8%以上；有无光照及光周期的长短对种子的萌发无影响；对酸碱度不敏感，在pH 4~10范围内种子萌发率均在91.3%以上；对水势具有一定耐受力，抑制50%种子萌发率所需的水势为-0.42 MPa；盐分对野老鹳草种子萌发具有一定抑制作用，当盐浓度达到160 mmol/L时基本不能萌发；此外，种子在土壤垂直深度5 cm以内时仍然可以出苗，对播种深度适应性较强。表明野老鹳草种子具有较长休眠期，土壤层积可解除种子休眠；而且野老鹳草种子对温度、光照、土壤酸碱度、播种深度适应性较强，水势及盐分对种子萌发有一定影响。     

Effect of temperature on bulb growth capacity and sensitivity to summer sprouting in Lilium longiflorum Thunb.

The production of Lilium longiflorum bulbs in The Netherlands, with its cool climate, has been a problem because of unsatisfactory bulb growth and the risk of premature sprouting of the daughter bulbs (summer sprouting). To investigate the possibilities of breeding a type of L. longiflorum that can be grown under cool climatic conditions, a collection of 27 L. longiflorum cultivars from Japan, The Netherlands and the United States was tested, together with two Asiatic hybrids and a L. speciosum cultivar, under low phytotron temperatures (10, 14, 17°C) and in field experiments.‘Mount Everest’, ‘Saeki’, ‘Indian Summer’ and ‘White American’ were among the best L. longiflorum cultivars, with less than 20% summer sprouting and good bulb production. This was in contrast to ‘Hinomoto’, ‘Ace’ and some American introductions, which showed more than 60% summer sprouting and low bulb production. The lower the phytotron temperature, the more summer sprouting occurred. The differences observed between the cultivars in the field experiments were in agreement with those observed in the phytotron. The genetic variation proved large enough to start a breeding program for L. longiflorum adapted to cool climate conditions.     

Effects of variation in seed sources and pre-sowing treatments on seed germination of Tamarindus indica: a multi-purpose tree species in Bangladesh

We investigated the morphology and germination of Tamarindus indica seeds in order to discover the effects of variation in seed sources and pre-sowing treatments on germination. The experiment was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh. Seeds were collected from different but healthy trees from various locations in Bangladesh and subjected to four pre-sowing treatments, i.e., control, immersion in cold water (4°C for 24 h), immersion in hot water (80°C for 10 min) and scarification with sand paper. Seed germination was carried out in poly-bags with a mixture of topsoil and cow dung in the ratio of 3:1. The average length of the fresh seeds was 1.35±0.26 cm, their width 1.07 ±0.20 cm and thickness 0.69±0.11 cm. The results revealed that pre-sowing treatments affected the germination process of seeds, which significantly increased the germination percentage with the cold water (81.67%) and scarification with sand paper (82.33%) treatments, compared with those in the control (58.33%) and hot water treatment (59.00%). In all treatments germination started on average within 5 to 7 days after the start of the treatments and were completed from 13 to 19 days later. The greatest success in germination (82.33%) was found in scarification with sand paper, followed with 81.67% in the cold water treatment. The results of analyses of variance (ANOVA) showed significant differences (p<0.05) in germination closing dates, seed germination periods and germination percentages among the treatments but no significant difference among seed sources. However, the effect of the interaction between seed source variation and pre-treatment differed significantly in seed germination closing dates and germination percentages. We recommend cold water treatment (submersion of seed at a temperature of 4°C for a 24-h period) for seed germination of T. indica in rural Bangladesh.     

老芒麦种子人工加速老化条件的筛选比较

以4份不同发芽水平的老芒麦(Elymus sibiricus Linn.)种子作为试验材料,研究比较老化温度(39、41、43℃和45℃)和老化时间(1、2、3、4、5、6、7 d)处理对种子发芽率的影响,筛选确定老芒麦种子进行人工加速老化测定的适宜条件,并建立标准化的测定程序。结果表明:随着老化温度升高,Lot1、Lot2和Lot3样品种子发芽率均下降,且各处理间均差异显著(p<0.05),只有Lot 3在45℃条件下老化后发芽率下降的比例最低;Lot 4样品种子老化后发芽率较低,且45℃处理与其他各处理间均差异显著(p<0.05)。随着老化时间延长,Lot 1和Lot 2老芒麦种子老化发芽率不断降低,老化1、2 d处理与其他各处理发芽率间差异显著(p<0.05);Lot 3和Lot 4老芒麦种子老化至第4天后发芽率出现峰值。老化温度与老化时间互作效应与种子发芽率和休眠程度有关,且对老芒麦种子老化发芽率具有极显著(p<0.01)的影响。老芒麦种子人工加速老化处理的适宜条件为温度45℃老化2 d。