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1.
爆裂玉米胚乳数量性状的遗传研究   总被引:7,自引:1,他引:6  
采用三倍体胚乳种子遗传模型及其分析方法,研究了4个爆裂玉米膨爆特性的胚乳直接效应、母体效应和细胞质效应。结果表明,百粒重、膨化体积的遗传同时由3套遗传体系所控制,百粒重的细胞质、膨化体积的母体和细胞质遗传率较高。爆花率和膨化倍数受胚乳和母体2套遗传体系的影响,且遗传率相近。爆花率和膨化倍数的直接和母体杂种优势均为负值。要组配出优良爆裂玉米杂交种,必须首先选育出膨爆特性突出的自交系,同时还要注意不同自交系的恰当组配。在6个供试自交系中,必须首先选育出膨爆特性突出的自交系,同时还要注意不同自交系的恰当组配。在6个供试自交系中,P3,P4适宜用作母本,P5则适宜作父本。  相似文献   

2.
Popping expansion volume is the most important quality trait in popcorn ( Zea mays L.), but its genetics is not well understood. The objectives of this study were to map quantitative trait loci (QTLs) responsible for popping expansion volume in a popcorn x dent corn cross, and to compare the predicted efficiencies of phenotypic selection, marker-based selection, and marker-assisted selection for popping expansion volume. Of 259 simple sequence repeat (SSR) primer pairs screened, 83 pairs were polymorphic between the H123 (dent corn) and AG19 (popcorn) parental inbreds. Popping test data were obtained for 160 S(1) families developed from the [AG19(H123 x AG19)] BC(1) population. The heritability ( h(2)) for popping expansion volume on an S(1) family mean basis was 0.73. The presence of the gametophyte factor Ga1(s) in popcorn complicates the analysis of popcorn x dent corn crosses. But, from a practical perspective, the linkage between a favorable QTL allele and Ga1(s) in popcorn will lead to selection for the favorable QTL allele. Four QTLs, on chromosomes 1S, 3S, 5S and 5L, jointly explained 45% of the phenotypic variation. Marker-based selection for popping expansion volume would require less time and work than phenotypic selection. But due to the high h(2) of popping expansion volume, marker-based selection was predicted to be only 92% as efficient as phenotypic selection. Marker-assisted selection, which comprises index selection on phenotypic and marker scores, was predicted to be 106% as efficient as phenotypic selection. Overall, our results suggest that phenotypic selection will remain the preferred method for selection in popcorn x dent corn crosses.  相似文献   

3.
P Vernon  G Vannier  V Arondel 《Cryobiology》1999,39(2):138-143
The influence of the water content of seeds and seedlings of Arabidopsis thaliana (Ecotype Columbia:2) on their supercooling capacity was investigated. Equilibration of the seeds to various air relative humidities resulted in final moisture contents ranging from 8 to 82% (dry weight basis). No supercooling point could be detected when the water content remained below 32.5%, and in seeds at just above this moisture level ice crystals started to form at -26 degrees C. However, cooling partly affected the germination of seeds down to a water content of 26.5%. Upon imbibition, the supercooling point of the seeds remained around -21.6 degrees C and rose sharply to -14.7 degrees C when visible germination started. It remained around -13 degrees C during the following 96 h while the water content of the seedlings increased from 155 to 870%. Hydrated seeds (above 32.5% water content), germinated seeds, and seedlings of Arabidopsis cannot survive being frozen.  相似文献   

4.
A series of experiments were carried out to study the effects of different drying regimes on the survival of newly-germinated (radicle emerged 0·5-1·5 mm through the seed coat) cabbage seeds and to establish a treatment for reducing the moisture content of these germinated seeds. A preliminary surface-drying step proved necessary to avoid seed agglutination during the main drying stage. Of the drying regimes compared both viability and vigour were most effectively maintained in air, conditioned to between 20 and 30°C and with 80% r.h., flowing through the seeds at 0·25 m s-1. Under these conditions, the viability and vigour of newly-germinated seed was maintained during drying to an equilibrium moisture content of c. 14%. At this moisture content further radicle growth was prevented and seeds remained free-flowing and separate for sowing or for further treatment.  相似文献   

5.
ABSTRACT: BACKGROUND: Nuna bean is a type of ancient common bean (Phaseolus vulgaris L.) native to the Andean region of South America, whose seeds possess the unusual property of popping. The nutritional features of popped seeds make them a healthy low fat and high protein snack. However, flowering of nuna bean only takes place under short-day photoperiod conditions, which means a difficulty to extend production to areas where such conditions do not prevail. Therefore, breeding programs of adaptation traits will facilitate the diversification of the bean crops and the development of new varieties with enhanced healthy properties. Although the popping trait has been profusely studied in maize (popcorn), little is known about the biology and genetic basis of the popping ability in common bean. To obtain insights into the genetics of popping ability related traits of nuna bean, a comprehensive quantitative trait loci (QTL) analysis was performed to detect single-locus and epistatic QTLs responsible for the phenotypic variance observed in these traits. RESULTS: A mapping population of 185 recombinant inbred lines (RILs) derived from a cross between two Andean common bean genotypes was evaluated for three popping related traits, popping dimension index (PDI), expansion coefficient (EC), and percentage of unpopped seeds (PUS), in five different environmental conditions. The genetic map constructed included 193 loci across 12 linkage groups (LGs), covering a genetic distance of 822.1 cM, with an average of 4.3 cM per marker. Individual and multi-environment QTL analyses detected a total of nineteen single-locus QTLs, highlighting among them the co-localized QTLs for the three popping ability traits placed on LGs 3, 5, 6, and 7, which together explained 24.9, 14.5, and 25.3 % of the phenotypic variance for PDI, EC, and PUS, respectively. Interestingly, epistatic interactions among QTLs have been detected, which could have a key role in the genetic control of popping. CONCLUSIONS: The QTLs here reported constitute useful tools for marker assisted selection breeding programs aimed at improving nuna bean cultivars, as well as for extending our knowledge of the genetic determinants and genotype x environment interaction involved in the popping ability traits of this bean crop.  相似文献   

6.
Lettuce seeds were stored under aerobic conditions at varioustemperatures from 20 ?C to 35 ?C, under anaerobic conditionsat 35 ?C, and at various moisture contents ranging from 17%to 44%, controlled osmotically by polyethyleneglycol. Survivalof these seeds was compared with others maintained over a similarrange of temperatures and moisture contents but in which themoisture contents were controlled by hermetic storage. Irrespectiveof the method of controlling moisture content, under anaerobicconditions the trend (shown previously in drier seeds) of decreasein longevity with increase in hydration continued up to about27% moisture content, but above this value there was no furtherchange in longevity. In contrast, under aerobic conditions longevityincreased exponentially up to 44% moisture content, this increasestarting at about 15% moisture content at 20 ?C and at about24% at 35 ?C. Under all circumstances longevity was less athigher temperatures. On a water substrate, thermodormant seeds showed a rapid increasein rate of oxygen uptake, followed by a rapid decline, and thena slower decline to a steady state. Similar phases were shownin seeds of various moisture contents controlled osmoticallydown to 17%, although the corresponding rates were lower withdecrease in moisture content and temperature, and the phaseswere extended at lower temperatures. The implications of these results are discussed in relationto the conditions needed to sustain sub-cellular repair andturnover as postulated by Villiers. Key words: Lettuce, Lactuca sativa L, Seed viability, Seed storage, Respiration  相似文献   

7.
Since moisture loss of popcorn can cause an increase in the number of unpopped kernels, pericarp properties of popcorn hybrids were analyzed to understand factors affecting moisture loss rate during microwave heating. Differential scanning calorimetry profiles of ground pericarp displayed a notable exothermal event, and hybrids with superior microwave popping performance (fewer unpopped kernels) exhibited significantly higher enthalpies. The number of unpopped kernels was highly correlated (r = 0.826, p = 0.011) with pericarp enthalpy values. X-ray analysis confirmed that cellulose and arabinoxylan are the major structural components of the pericarp. Structural changes in cellulose were induced by moisture and heat, and considerable enhancement in crystallinity occurred when the pericarp was heated in the presence of water. Results of this study indicate that the cellulose component of the pericarp is responsible for the development of exothermal events and increased crystallinity. Thus, the propensity of cellulose to form crystalline structures in the popcorn pericarp during microwave heating improves moisture retention and hence popping performance.  相似文献   

8.
Effects of 2 °C chilling on the threshold moisture contentsand water potentials for various physiological processes wereestimated forAesculus hippocastanumL. seed. Seed harvested atthe time of maximum seed fall exhibited a dual response to drying:partial drying from near 50% to 32–40% moisture contentprogressively increased germination percentage (at 16 °C)up to various peak values; further desiccation was detrimental,confirming that the seeds are ‘recalcitrant’. Themoisture content for optimum germination was increased by atleast 10% as the chilling period was raised from 0 to 9 weeks.A negative linear relationship was found between log10mean timeto germinate and probit final germination, regardless of pre-treatment,indicating that partial desiccation and chilling are interchangeablein promoting germination of hydrated seed. For nearly fullyhydrated seeds, increasing the chilling period from 6 to 26weeks increased the viability-loss onset point for desiccationinjury from near 40% to about 48% moisture content without alteringthe drying rates of seed tissues. Extending moist chilling invarious seed lots from 0 to 26 weeks decreased subsequent longevityat 16 °C. For 26-week-chilled seeds longevity (the periodto lose one probit of germination) differed above and belowa threshold moisture content of 48%. It remained constant inthe moisture-content range 48–38%, but increased progressivelyas moisture content was raised above 48%. This threshold moisturecontent coincided with the value above which chilled seed pre-germinatedin storage. The results indicate that post-harvest desiccationand chilling alter the water relations of various physiologicalprocesses and a schematic summary is presented which relatesthe results to an axis water sorption isotherm.Copyright 1998Annals of Botany Company Aesculus hippocastanumL., horse chestnut, chilling, moisture content, water potential, desiccation tolerance, longevity, recalcitrant seed, embryo axis, maturation, germination.  相似文献   

9.
文章对竹柏(Podocarpus nagi)种子的脱水耐性和贮藏特性进行了研究,结果表明:竹柏种子成熟时初始含水量约为(35±0.7)%,种子对脱水敏感,其最低安全含水量约为(16.86±0.73)%,具有顽拗性种子的典型特征;湿藏和半干藏都可以作为短期保存竹柏种子的方法,且以4℃保存优于15℃保存,但不管种子含水量如何,零下低温保存对竹柏种子都是致命的;半干藏法保存实验中,未进行脱水处理的种子(对照)在4℃贮藏6个月,种子萌发率没有发生明显下降,但贮藏期延长到9个月时,临界含水量的种子萌发力保存最高;不管贮藏介质的含水量高低,也无论贮藏在4℃还是15℃,湿藏种子在9个月的贮藏期内萌发率均没有明显的降低,但当贮藏到12个月时,15℃湿藏种子的萌发率显著高于4℃贮藏的种子,但15℃湿藏的种子在贮藏到3个月时即发现种子在贮藏期间萌发,且随着贮藏介质含水量的升高和贮藏期的延长,萌发的种子增多;竹柏的离体胚经过2 h硅胶快速脱水至含水量7%后再冷冻即可获得90%以上的融后存活率,且超低温保存1年的离体胚解冻后,与只保存1周的存活率没有明显差异,表明超低温长期保存竹柏种子是可行的。本研究可以为进一步探究顽拗性种子的短期贮藏和长期保存提供理论基础和基础资料。  相似文献   

10.
Sun-dried French bean seeds, moisture content 10 ± 0·8%, aged at ambient temperature for 2 months, 1, 2, 3 and 4 yr were incubated in hot water at 58 × 1°C for 30 min. Buffering capacity of incubation water (IWBC) due to solutes leaked out into hot water was highly correlated with electrolyte leakage into single seed steep water. The IWBC was examined for its ability to predict seed quality of ageing stocks. The technique does not require any instrument. Thus it may prove useful as a rapid, simple, inexpensive and highly predictive vigour test.  相似文献   

11.
Summary The formation and subsequent growth of roots by cuttings of poinsettia, hydrangea, rose and azalea in various propagation media, Jiffy-7, Jiffy-9 and Grodan under different conditions of aeration was investigated. The interrelationships of the effects of air content of the media, temperature and light intensity on the rooting of poinsettia cuttings was also studied.With low air contents (0 cm moisture tension) in the propagation media the formation and growth of roots was strongly inhibited. The rooting performance of rose appeared to be less affected by the poor aeration. Increasing air content improved rooting but best results were obtained at moisture tensions of 4 to 8 cm. Rooting seems to be better correlated with oxygen diffusion rate (ODR) than with air content.For poinsettia cuttings the optimum temperature for rooting was 24 to 28°C. At low temperatures rooting was delayed while at higher temperatures it was almost completely inhibited. Callus formation increased with temperature but decreased with increasing moisture tension. Conditions which induced large callus formation inhibited root formation.High light intensity during rooting reduced overall rooting performance and the inhibition was most pronounced in conjunction with high moisture tensions.Report No. 255.  相似文献   

12.
Study and characterization of a novel functional food: purple popcorn   总被引:1,自引:0,他引:1  
Many phytonutrients seem to be able to combat the effects of oxidants which may lead to chronic diseases. Among them, anthocyanins have been studied for a long time, and different types of functional foods rich in these pigments are already available on the market. In particular, wine, berries and various cereals have already aroused consumers’ awareness, and in this context we propose a new and attractive healthy food: purple popcorn. Popcorn is the most popular American snack, now well known all over the world. A corn rich in anthocyanins, suitable to be transformed into a snack, could help to introduce healthy antioxidant compounds into the diet of many people, contributing to the prevention of chronic diseases. In this work we developed a coloured popcorn variety rich in anthocyanins (about 66 mg/100 g, mainly cyanidin) by a recurrent selection scheme, with the aim of obtaining a healthier snack. The selection was based on some quality characteristics such as anthocyanin content, popping ability and the popping expansion volume. The purple popcorn obtained was further analyzed by high pressure liquid chromatography and 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability, before and after microwave treatment. The results obtained showed that, even though the microwave treatment reduced the anthocyanin content to about 46 %, the remaining anthocyanins exhibited a marked antioxidant capacity compared to the colourless control. Finally taste perception was also checked between coloured and uncoloured popcorn, and no difference was perceived.  相似文献   

13.
The relationship of seed moisture content (fresh weight basis) to germination, and the effect on viability of various storage conditions were examined for five species of the tropical forest tree genus Dipterocarpus. It was shown that seeds fall into two groups with regard to desiccation tolerance. Firstly, D. obtusifolius and D. turbinatus cannot be dried below about 45% moisture content without damage; a sigmoid curve was found to fit the relationship between germination and moisture content for the latter species. Secondly, D. intricatus, D. tuberculatus and D. alatus can be safely dried to 10%, 12% and 17% moisture contents respectively, but desiccation to near 7% moisture content reduced viability by at least a half. Storage studies showed that seed of D. intricatus and D. tuberculatus possessed increased longevity as moisture contents were reduced within the range 6–20%. It was concluded that seeds in the first group are ‘recalcitrant’ and that those in the second group are ‘orthodox’ in their storage physiology, according to the categories described by Roberts (1973). Wide differences between species in seed desiccation rates were observed. In 15% relative humidity D. intricatus dried to 7% moisture content within a week, whilst D. obtusifolius retained 30% moisture content even after 5 wk; other species had intermediate desiccation rates. Seed size and structure may partly account for the differences observed. Correlations were observed between seed storage physiology and other factors which were investigated. ‘Orthodox’ seeds had quicker desiccation rates, were derived from drier habitats, and had smaller embryos than those of ‘recalcitrant’ seeds. ‘Orthodox’ seeds, with the possible exception of D. alatus, should be kept at 0–3°C with about 12% moisture content in the short term and, provided less than 10% germination is lost on freezing, at-18°C with about 8% moisture content in the long term. ‘Recalcitrant’ seeds should be stored in ventilated containers at 21°C and with moisture contents above 45–50%.  相似文献   

14.
Amaranth is a dicotyledonous plant whose major seed storage proteins are globulins and glutelins. An unique feature of amaranth seeds is the presence of a fraction named albumin-2, that is extractable with water only after an exhaustive extraction of globulins and albumin-1. In this work, we tested the hypothesis that albumin-2 fraction could be constituted by a non-processed 11S globulin (proglobulin). To this end, the gene encoding the amaranth 11S subunit was cloned and expressed in Escherichia coli. Subsequently, the recombinant proglobulin and albumin-2 purified from seeds were treated with a sunflower vacuolar processing enzyme (VPE). A 55 kDa component of albumin-2 was specifically cleaved into 38 and 17-15 kDa polypeptides, as a consequence of this endoproteolytic cleavage a change of the oligomeric state from trimeric to hexameric was observed. Amaranth 11S globulin fraction was not modified under these proteolysis conditions. Using VPE-specific antibodies, it was shown that amaranth expresses a 57 kDa VPE, and that both developing and mature amaranth seeds have VPE activity, although the increase of this activity during amaranth seed development is higher than that observed for sunflower seeds. These results confirm the presence of unprocessed 11S precursors in mature amaranth seeds; this phenomenon cannot, however, be attributed to low VPE activity during developing of amaranth seeds.  相似文献   

15.
Mango (Mangifera indica L.) seed is recalitrant which taken from ripened fruits con,ained as high as 69.2'–75.5% moisture content (The moisture content of embryonic axis is 73.8–86.3%). When seeds were naturally dried for 8 days, the moisture content declined to 39.1% (in embryonic axis the moisture content declined to 46.5%) and the viability of seeds completely lost. Embryonic axis lost water slower than whole seed because of the prevention of desiccation by the large cotyledons. During natural desiccation, the conductivity of leachate increased rapidly from 2.2 μΩ·cm-1·g-1 (the same unit below) to 56.7, whereas the activities of dehydrogenase and acid phosphatase decreased drastically. When seeds were rapidly dried for 42 hours, the moisture content declined from 75.5 to 29.9%, the conductivity of leachate increased from 1.8 to 36.9 and the percentage germination changed from 100% to 10%. Desiccation damaged the cell membrane and decreased the activities of enzymes. Rapid drying was better for maintaining longevity than natural (slow) drying because the former did less damage to the cell membrane than natural (slow) drying as shown in the conductivity changes. The moisture content of excised embryonic axis decreased to 11.8% when they were dried for 8 hours by silicagel. The survival percentage of these embryonic axis was 80% when they were incubated in MS+0.2 mg/L BA+2.0 mg/L NAA+500 mg/L gln+3% sucrose+0–9% agar medium. Seeds with 51.0% moisture content (rapidly dried for l0 hours by electric fan blowing) had 65% viability after 7 months wet storage with the polyethylene bag at 15℃.  相似文献   

16.
Relationship between water content and afterripening in red rice   总被引:2,自引:0,他引:2  
Reactions regulating seed dormancy can proceed at water contents which are probably too low to permit metabolic activity. The loss of dormancy via afterripening of red rice. ( Oryza sativa L.) seeds was examined as a representative case. Equilibration of seeds to various moisture contents showed that afterripening was most rapid at 6–14% moisture content (dry weight basis). Afterripening did not occur at > 18% moisture content and was severely inhibited at < 5% moisture content. Seed viability was greater than 95% for all treatments. Utilization of moisture isotherms to calculate water-binding enthalpy values identified the optimal afterripening range as approximately the boundary between water-binding region 1 and region 2. From these findings, it is suggested that afterripening may involve some oxidative reactions which are inhibited at lower water contents by the rising free-energy and at the higher side by metabolic reactions.  相似文献   

17.
茸毛赤瓟种子自花后30 d发育至55 d,发芽率、发芽指数和活力指数由0升至最大;含水量逐渐下降,但下降速率不等,发育后期存在显著的成熟脱水期。花后45 d果实干重接近最大,种子干重在45 d达到最大,种子和果实的发育基本同步。自然风干1d后,花后40~50 d的种子含水量下降2%~4%。花后40 d的种子发芽力显著提高,花后45~50 d的种子无明显变化,继续干燥,发芽率、发芽指数和活力指数均有不同程度的降低,而花后50 d的种子直到含水量低至4%后才明显下降;花后35 d和55 d的种子经过不同天数干燥后,发芽力均下降。不同发育时期茸毛赤瓟种子耐脱水力有差别,由强至弱依次为花后50、45、55、40、35 d。用半致死含水量可准确地反映不同发育时期茸毛赤瓟种子的脱水敏感性的强弱。  相似文献   

18.
TOMPSETT  P. B. 《Annals of botany》1982,50(5):693-704
Seeds of Araucaria hunsteinii K. Schum. dried quicker at 29°Cthan at 19°C and quicker with the seed-coat removed thanwhen intact; seeds enclosed in polyethylene bags increased inmoisture content. At 15°C, seeds in a flow of air driedquicker than seeds in a box with silica gel, which in turn driedquicker than seeds in a box with no desiccant. No loss of germinationability occurred on drying fresh seed from 53 to about 32 percent moisture content (fresh weight basis); during further desiccationthe percentage germination was related to percentage moisturecontent in the form of a sigmoid curve, culminating in a completefailure to germinate at approximately 14 per cent moisture content.A consistent relationship was observed for all treatments andthe mean critical moisture content for seed death (failure togerminate) was near 23 per cent. Excised embryos grew on 1 percent agar but died if previously subjected to 14 h of desiccationat 15°C. In contrast, no relationship was found between germination andmoisture content of A. cunninghamii D. Don on desiccation from21 to 7 per cent moisture content. Possible causes for the observeddifference in response to desiccation are discussed and methodsfor seed storage are considered. Araucaria hunsteinii, Klinkii pine, Araucaria cunninghamii, Hoop pine, desiccation, seed longevity, storage of seeds  相似文献   

19.
When watermelon seeds were cultured in a Petri dish together with amaranth, barnyard grass, cockscomb, lettuce or tomato seeds, the shoot growth of amaranth and cockscomb was markedly promoted, whereas the shoot growth of lettuce and tomato was inhibited. The shoot growth of barnyard grass was not affected. These results suggest that plant-selective allelopathic substance(s) affecting the shoot growth of other plant seedlings were exuded from watermelon seeds. An allelopathic substance was isolated from the exudates of germinating watermelon seeds and identified as vanillic acid by its spectral analysis and Rf value on TLC. Vanillic acid promoted the shoot growth of cockscomb at the concentrations of 300 to 10 mg/l and that of amaranth at the concentrations of 30 to 3 mg/l, although the shoot growth of amaranth was inhibited by 300 mg/l of vanillic acid. The shoot growth of lettuce and tomato was inhibited at the concentrations higher than 30 mg/l by vanillic acid. However, the shoot growth of barnyard grass was not affected at the concentrations used. All these results suggest that vanillic acid may play as a major component of allelopathic substance(s), which shows plant-selective activity, in the exudates of germinating watermelon seeds.  相似文献   

20.
Legume seed products are used extensively in human and animal nutrition, but high levels of inclusion are often avoided as their secondary compounds can interfere with digestion and absorption of nutrients in the digestive tract. Due to the well-known benefits of some physicochemical treatments on nutritional value, this experiment was completed to assess effects of soaking and heat treatment on the nutritional value of dehulled and hulled X’pelon seeds (Vigna unguiculata (L.) Walp) to Nile tilapia (Oreochromis niloticus) fingerlings. Seeds were soaked for 16 h in a 2 g/kg sodium bisulphate solution in water. Seeds were divided into two lots, being hulled and dehulled. Three heat treatments were used to convert the seeds to meal, being 5 h of hot air flow (70 °C); autoclaving at 119 °C for 30 min to 1.05 kg/cm2, and 7 h in a forced air oven at 48 °C. The resultant crude protein (CP) quality of each meal was evaluated by amino acid analysis and by a tilapia feeding study in which fingerlings were fed one of eight diets, each containing 350 g CP/kg of DM, of which seven diets were formulated with 0.80 of CP provided by fish meal and 0.20 by the X’pelon meals and one control diet was formulated with fish meal as the sole CP source. The study encompassed 9 weeks during which fingerlings were fed ad libitum. Chemical and secondary compound analysis of treated seeds showed that heat flow reduced phytic acid by 34.9% and trypsin inhibitors and hemaglutinin decreased by 94.5%, while complete elimination was obtained with autoclaving. Soaking and heat treatment are suitable for partial or complete elimination of the secondary compounds of X’pelon seeds without affecting the content and bioavailability of amino acids, with heat treatment by hot air flow the best. Partial replacement of fish meal with X’pelon meal improved growth and feed efficiency of Nile tilapia, whether the meal was treated or raw.  相似文献   

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