首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 453 毫秒
1.
Secondary metabolites (SMs), such as alkaloids and raffinose oligosaccharides (RFOs), play important roles in plant physiology. Although alkaloid and RFO phenotypic variation has been reported for yellow lupin (Lupinus luteus L.), most evaluations have used a reduced number of accessions; thus, limiting the understanding of accumulation patterns and variation ranges. The main goal of this research was to assess alkaloid and RFO content in a diverse L. luteus sample to understand possible SM accumulation patterns across this legume species. Eighteen yellow lupin accessions were analyzed using high performance thin layer chromatography to provide insights on seed and leaf RFO and alkaloid phenotypic variation. Co-dominant markers (170) were used to examine genetic relationships among L. luteus accessions and possible accumulation patterns across closely related genotypes. Significant differences were observed for seed and leaf RFOs. Total seed RFO accumulation ranged from 79.738 to 131.079 mg g?1. Raffinose, stachyose, and verbascose were observed in all genotypes’ seeds, but at different RFO concentrations. Raffinose was the only RFO detected in leaves (2.793–0.4224 mg g?1). Total alkaloid accumulation ranged from 0.22 to 15.12 and 0.00 to 8.007 mg g?1 for seeds and leaves, respectively. Lupinine, sparteine, and gramine were observed in seeds and leaves, and showed a wide range of variation. Neighbor-Joining (NJ) analysis showed an apparent pattern of seed alkaloid accumulation, most likely due to domestication events. However, high RFO accumulating accessions were scattered across the NJ tree. Alkaloid and RFO significant phenotypic variation will not only help to understand the roles of these SMs in L. luteus, but also to uncover the genetic basis behind their accumulation.  相似文献   

2.
Plants of the Pilocarpus genus (Rutaceae) are popularly known as jaborandi and are the only source of pilocarpine, an imidazole alkaloid used in eye-drops for the treatment of glaucoma as well as for the stimulation of sweat and lachrymal glands. Alkaloid extracts from leaf samples of seven species of Pilocarpus, from the states of São Paulo and Maranhão in Brazil, were analyzed using HPLC–ESI–MS/MS. The samples contained between 0.88 ± 0.04 and 1.00 ± 0.14% of alkaloids in relation to the dry weight of their leaves, with significant differences in results (P ≤ 0.05) found only between Pilocarpus microphyllus planted in the state of Maranhão and Pilocarpus spicatus, Pilocarpus trachyllophus, Pilocarpus pennatifolius and Pilocarpus jaborandi; as well as between Pilocarpus spicatus and Pilocarpus racemosus. Pilocarpine was not found in P. spicatus, whereas in the other species it ranged from 2.6 ± 0.1 to 70.8 ± 1.2% of total alkaloids. P. microphyllus planted in the state of Maranhão for pilocarpine extraction had the highest total alkaloid content, but it had only 35% of pilocarpine in relation to total alkaloids. Three other species contained more pilocarpine in relation to total alkaloids: P. jaborandi (70.8%), P. racemosus (45.6%) and P. trachyllophus (38.7%); and could be candidates for pilocarpine extraction. Differences in alkaloid content were significant for all these samples (P ≤ 0.05). Imidazole alkaloids were observed and partially characterized based on their retention times and high resolution mass. The seven species analyzed had different imidazole alkaloid profiles, but only one did not present quantifiable pilocarpine contents in its leaves. The Pilocarpus genus shows potential for the prospection of novel alkaloids.  相似文献   

3.
The content of raffinose family oligosaccharides (RFOs) in pea seeds constrains their usage in feeding humans and animals. In our research, the content of soluble carbohydrates—particularly α-d-galactosides of sucrose (RFOs)—was analyzed. The materials were as follows: 248 accessions from the Polish Pisum Genebank including representatives of taxa (from species to convarietas), type lines for genes controlling seed characters, and breeding materials and cultivars. Accessions were divided into homogeneous groups considering content of total soluble carbohydrates, total RFOs and individual RFOs: raffinose, stachyose and verbascose. The highest content of total soluble carbohydrates and total RFOs were stated for accessions with wrinkled seeds (r and rb genes) and the lowest content for seeds of the wild species P. fulvum Sibth. et Sm. Accessions valuable for breeding (for further decreasing of anti-nutritional compounds) were found among domesticated taxa (P. sativum subsp. sativum convar. vulgare Alef. and speciosum (Dierb.) Alef.), breeding lines, and some wild taxa. Accessions with decreased content of a total RFOs and verbascose are particularly valuable. It was found that the content of total RFOs was the most highly, frequently, and positively correlated with a stachyose and verbascose content. However, in P. fulvum seeds with the lowest content of RFOs and verbascose, a high correlation between the content of total RFOs and stachyose was revealed. Contents of all oligosaccharides were substantially lower in lines with dominant alleles of main pea seed genes (R, A, and I). It can be assumed that wild, primitive peas were characterized by not-all-to-high (rather not high) content of oligosaccharides; then recessive mutations in mentioned genes resulted in an increased content of RFOs. It seems to be an interesting observation from an evolutionary point of view.  相似文献   

4.
The paper assess the variability of fat content and fatty acids profiles in seeds of a white lupin (Lupinus albus L.) domestic collection. The initial material comprised 371 accessions originated from 30 countries of Europe, Asia, Africa, North- and South America and Australia. According to data given by accession donors the material is divided into four classes of origin: wild lines, landraces, lines created by man and cultivars. Variability of fat content and fatty acids composition were estimated in seeds of each accession. The average fat content for analyzed collection is 9.81%. The broadest range of fat content was noticed for landraces and cultivars as compared to narrowest represented by lines created by man. Fat content ranged from 6.9% (induced mutant Wt 95497) to 14.1% (Polish cultivar Wt 95420 and the landrace Wt 95212 from Jordan). From a dietetic point of view, oil quality is more important than oil quantity in lupin seeds. On average the fatty acid (FA) in examined accessions ranked in following order of abundance: oleic acid (C18:1) > linoleic acid (C18:2) > linolenic acid (C18:3) > palmitic acid (C16:0) > eicosenoic acid (C20:1) > stearic acid (C18:0) ≈ erucic acid (C22:1). In respect to unsaturated fatty acid (UFA), monounsaturated oleic acid in each of estimated classes of accessions was predominant and most abundant (55.7%) in broad range of minimum–maximum values from 41.2 to 66.2%. The second examined monounsaturated fatty acid was erucic acid (1.74%) found in seeds of almost all studied accessions. An exception were four accessions defined similarly to rapeseeds as “zero erucic” forms. In seeds of few accessions a content of erucic acid exceeded 3%. Among polyunsaturated fatty acids linoleic FA (ω?6) dominated followed by linolenic FA (ω?3). Both FA were in the range 13.7–33.2% and 5.6–12.8% with mean values on the level 19.6 and 10.1%, respectively. As a consequence, the examined white lupin seeds showed a very favourable ω?3/ω?6 FA ratio (0.51), ranging from 0.21 to 0.87, much higher than that of most vegetable oils. Fat content was positively correlated with stearic and oleic fatty acids and negatively with palmitic, linoleic, linolenic and erucic acid.  相似文献   

5.
Yam bean [Pachyrhizus DC.] is a legume genus of the subtribe Glycininae with three root crop species [P. erosus (L.) Urban, P. tuberosus (Lam.) Spreng., and P. ahipa (Wedd.) Parodi]. Two of the four cultivar groups found in P. tuberosus were studied: the roots of ‘Ashipa’ cultivars with low root dry matter (DM) content similar to P. erosus and P. ahipa are traditionally consumed raw as fruits, whereas ‘Chuin’ cultivars with high root DM content are cooked and consumed like manioc roots. Interspecific hybrids between yam bean species are generally completely fertile. This study examines the genetic diversity of the three crop species, their potentials for breeding and the identification of useful traits to differentiate among yam bean genotypes and accessions. In total, 34 entries (genotypes and accessions) were grown during 2000?2001 at two locations in Benin, West Africa, and 75 morphological and agronomical traits, encompassing 50 quantitative and 25 qualitative characters were measured. Diversity between entries was analyzed using principal component analysis, cluster analysis, multivariate analysis of variance and discriminant function analysis. Furthermore, phenotypic variation within and among species was investigated. Intra- and interspecific phenotypic diversity was quantified using the Shannon–Weaver diversity index. A character discard was tested by variance component estimations and multiple regression analysis. Quantitative trait variation ranged from 0.81 (for total harvest index) to 49.35% (for no. of storage roots per plant). Interspecific phenotypic variation was higher than intraspecific for quantitative traits in contrast to qualitative characters. Phenotypic variation was higher in overall for quantitative than qualitative traits. In general, intraspecific phenotypic variation ranged from 0.00 to 82.61%, and from 0.00 to 80.03% for quantitative and qualitative traits, respectively. Interspecific phenotypic variation ranged from 0.00 to 95.02%, and 0.00?81.58% for the two trait types, respectively. The Shannon–Weaver diversity index (H′) was in general high and over 0.80 for most of the trait. Diversity within P. tuberosus was higher than within P. erosus and P. ahipa. Across the 50 quantitative and 25 qualitative traits, the Shannon–Weaver diversity index of intra- and interspecific variation was around 0.83 and 0.51, respectively and was lower for qualitative than for quantitative traits. Monomorphism was observed in eight qualitative traits and one quantitative character. The first, second and third principal components explained, respectively, 39.1, 21.3 and 8.3% of the total variation in all traits. Pachyrhizus erosus, P. ahipa, and P. tuberosus (‘Chuin’ and ‘Ashipa’) were clearly separated from each other by these analyses. Multivariate analysis of variance indicates significant differences between Pachyrhizus species for all individual or grouped traits. Discriminant function analysis revealed that the first two discriminant functions were almost significant. Biases due to unbalanced sample size used per species were small. Within each species a similar amount of diversity was observed and was determinable to 70% by only ten traits. We conclude that the cultivated yam bean species represent distinct genepools and each exhibits similarly large amounts of genetic diversity.  相似文献   

6.
Significant genetic diversity was observed in 218 out of a total of 1309 accessions of amaranth (Amaranthus hypochondriacus L.) and its seven wild relatives, A. spinosus L., A. dubius Mart. ex Thell., A. hybridus L., A. tricolor L., A. cruentus L., A. caudatus L., A. retroflexus L. for 24 nutritional parameters including total oil content, fatty acid profile, total protein content and amino acid profile. Diversity for total oil content (6.42–12.53%), linoleic acid (25.68–54.34%), oleic acid (21.97–42.01%) of the total fatty acids, total protein content (7.84–18.01%), among important essential amino acids; lysine content (0.66–11.12 g/16 g N), methionine (0.35–4.80 g/16 g N) and half cystine and (0.12–8.32 g/16 g N) was reported. The un-weighted pair-group method using arithmetic average cluster analysis based on pair wise Euclidean genetic distance grouped the accessions into seven major clusters. Histidine, half cystine, tyrosine, essential amino acids, total oil content, linoleic acid and oleic acid content were the major parameters contributing significantly to genetic diversity. Present findings indicate that significant diversity exists for nutritional parameters in amaranth germplasm. The promising accessions with higher multiple nutritive traits; protein content (>16%), oil content (>11%), lysine content (>7.5 g/16 g N) and EAA higher than the FAO reported values, were identified. This is the first report on detailed nutritional analysis of diversity collected worldwide. These could be used as potential breeding material for nutritional enhancement through genetic improvement. This will help in overcoming the “triple burden” of malnourishment, hidden hunger, and obesity.  相似文献   

7.
The modern plant breeding is generally considered to be a practice that leads to a narrowing in genetic diversity of crops. The objective of the present study was to assess whether this practice has led to the reduction of genetic diversity in modern Chinese wheat cultivars. A set of 80 dominant Chinese wheat cultivars released from 1942 to 2011 was used to describe the genetic diversity based on 137 simple sequence repeat (SSR) and 52 functional markers. Several important properties about the genetic diversity were revealed. First, relative low genetic diversity level was detected on a genome-wide scale. A total of 752 alleles were detected with a range from 1 to 15, and the mean polymorphic information content value was 0.53 with a range from 0.00 to 0.87. Second, the genetic diversity significantly decreased from 2001 to 2011 at the genome-wide level. More importantly, significant differences of genetic diversity among the three different genomes were observed by the analysis of variance (ANOVA). The three genomes had clearly different changing trends over time: the A genome displayed a decreasing trend (regression coefficient (b) = ?0.01); in contrast, the other two genomes, B and D, showed the increasing trends (b = 0.01 for the B genome, P = 0.05; b = 0.01 for the D genome, P = 0.05). Third, the analysis of qualitative variations in allelic composition over time indicated that, the more recent the cultivars were, the more similar they were to each other. Finally, the frequencies of favorable alleles related to important agronomic traits had been increasing over time or maintained high frequencies in all seven temporal groups. These findings indicate that modern wheat breeding results in not only a qualitative, but also a quantitative change in genetic diversity in the dominant Chinese wheat cultivars. A special attention should be paid to broaden the genetic base in the A genome.  相似文献   

8.
The intake of lupin-based foods could imply the exposure of consumers to quinolizidine alkaloids. The objectives of this study were to assess the genetic variation among and within 11 geographic regions of Lupinus albus ecotypes, verify the quinolizidine alkaloids amount of alkaloid-poor L. albus and Lupinus angustifolius varieties, and assess the effect of two climatically contrasting Italian environments on the alkaloid content. The quantitation was performed by GC-MS, and in all samples lupanine was the most abundant quinolizidine alkaloid, followed by albine and 13alpha-hydroxylupanine for L. albus and by 13alpha-hydroxylupanine and angustifoline for L. angustifolius. Some regions tended to have a high (Azores) or low (Egypt, Near East, Maghreb) total alkaloids content, but the variation among ecotypes within regions was larger than that among regions following the estimation of variance components. Alkaloid-poor varieties tended to have higher total alkaloid contents when grown in the subcontinental climate site, exceeding in some cases the limit of 0.200 mg/g.  相似文献   

9.
Two Gram-negative bacterial strains capable of using lupanine, the predominant quinolizidine alkaloid in Lupinus albus, as a sole carbon source were isolated from soil in which L. albus and L. luteus had been grown [Santana, F. M. et al. J. Ind. Microbiol. 1996, 17, 110-115]. In the present study, we present results suggesting that these isolates are of potential interest for removing lupanine and other quinolizidine alkaloids (QA) from the effluent resulting from the wet processing of Lupinus seeds, at temperatures within the range 20-34 degrees C. Growth in L. albus aqueous extract was diauxic, with a first period of rapid growth leading to the simultaneous consumption of a significant part of the initial concentration of QA (3 g L(-1), being 2 g L(-1) lupanine) and amino acids (1.5 g L(-1)). This period was followed by a second period of slower growth corresponding to the subsequent partial utilization (25%) of the carbohydrates (initial concentration of 20 g L(-1)) together with further removal of QA and amino acids. Despite the differences detected in the susceptibility of the two strains to lupanine toxicity, in particular at supraoptimal temperatures, and in the efficiency of lupanine catabolism, their performance on L. albus extract did not vary significantly.  相似文献   

10.
After a century of banishment, both euphoric (“marijuana”) and non-euphoric (“industrial hemp”) classes of Cannabis sativa are attracting billions of dollars of investment as new legitimate crops. Most domesticated C. sativa is very tall, a phenotype that is desirable only for hemp fibre obtained from the stems. However, because the principal demands today are for chemicals from the inflorescence and oilseeds from the infructescence, an architecture maximizing reproductive tissues while minimizing stems is appropriate. Such a design was the basis of the greatest short-term increases in crop productivity in the history of agriculture: the creation of short-stature (“semi-dwarf”), high-harvest-index grain cultivars, especially by ideotype breeding, as demonstrated during the “Green Revolution.” This paradigm has considerable promise for C. sativa. The most critical dwarfing character for breeding such productivity into C. sativa is contraction of internodes. This reduces stem tissues (essentially a waste product except for fibre hemp) and results in compact inflorescences (which, on an area basis, maximize cannabinoid chemicals) and infructescences (which maximize oilseed production), as well as contributing to ease of harvesting and efficiency of production on an area basis. Four sources of germplasm useful for breeding semi-dwarf biotypes deserve special attention: (1) Naturally short northern Eurasian wild plants (often photoperiodically day-neutral, unlike like most biotypes) adapted to the stress of very short seasons by maximizing relative development of reproductive tissues. (2) Short, high-harvest-index, oilseed plants selected in northern regions of Eurasia. (3) “Indica type” marijuana, an ancient semi-dwarf cultigen tracing to the Afghanistan-Pakistan area. (4) Semi-dwarf strains of marijuana bred illegally in recent decades to avoid detection when grown clandestinely indoors for the black market. Although the high THC content in marijuana strains limits their usage as germplasm for low-THC cultivars, modern breeding techniques can control this variable. The current elimination of all marijuana germplasm from breeding of hemp cultivars is short-sighted because marijuana biotypes possess a particularly wide range of genes. There is an urgent need to develop public gene bank collections of Cannabis.  相似文献   

11.
  相似文献   

12.
Agaves are long-lived semelparous plants that produce a high number of seeds, in dehiscent capsules, on the apical section of a stalk, up to 5 m long, after 8–25 years. These and other characteristics such as yield and yield components are scarcely evaluated in the plants of the Agave genus. The objective of this study was to quantify the capsules and seeds yield of A. salmiana Otto ex Salm-Dyck plants simultaneously maturing and growing in the same region. Infructescences of three plants simultaneously growing at San Luis Potosí, Mexico, were harvested. On them we evaluated the number of umbels, capsules and seeds (normal and sterile) and their mass per plant. The study was developed on a completely randomized design with each infructescence as an experimental unit. Also, the type distribution of the number and mass of these yield components along the stalk was evaluated with the Chi square test for goodness of fit, the Shapiro–Wilks for normality tests, asymmetry and kurtosis. Data were analyzed with the ANOVA and multiple comparisons by the Tukey test (p?≤?0.05). The number of umbels per plant (17–25), capsule per umbel (2–179) and per plant (554–1990), normal seed per capsule (0–297), normal seeds per plant (30,610–186,209) and sterile seeds per plant (211,059–619,251) widely and significantly varied among infructescences. Biomass of capsules per plant umbel (3–795 g), biomass of sterile and normal seeds per capsule (0.071–1.449 and 0–3.320 g), per umbel (0.34–97.76 and 0.21–185.26 g) and per plant (182–1052 and 334–2069 g) also varied widely. Seed yield was statistically different between plants simultaneously growing and maturing at the same site.  相似文献   

13.
Raspberry cane disease, caused by a complex of fungi, is amongst the most devastating problems for raspberry production. Using resistant or highly tolerant genotypes is a promising strategy. However, until now, cultivars with good field resistance for German fruit growers as well as the primary causal pathogens of cane disease present in the eastern part of Germany, Saxony state are still unknown. The primary objective of this study was to identify the primary disease causing organisms and resistant Rubus germplasm for future breeding efforts. From 2012 to 2014, we evaluated the degree of susceptibility to cane diseases on 213 raspberry cultivars at two different locations using a rating scale. We also identified the main fungi growing on infected canes. Our results suggest that Fusarium avenaceum is the main fungus causing cane disease in Saxony. The Rubus hybrid cultivars ‘Tayberry’ (2n?=?6x?=?42), ‘Buckingham Tayberry’ (2n?=?6x?=?42) and ‘Dorman Red’ (2n?=?2x?=?14) displayed the highest levels of field resistance at both locations. Moreover, we established an in vitro assay for resistance evaluation which correlates significantly with field data and is particularly suitable for quick assessment of resistance against F. avenaceum in breeding material. Future breeding programs, aiming at cultivars with enhanced resistance towards cane diseases can use the presented data for parental selection and may employ our in vitro F. avenaceum inoculation method for parental testing and progeny selection.  相似文献   

14.
Developing a molecular tool kit for hybrid breeding of Osmanthus species and related genera is an important step in creating a systematic breeding program for this species. To date, molecular resources have been aimed solely at Osmanthus fragrans with little work to develop markers for other species and cultivars. The objectives of this study were to (1) determine cross-transferability of O. fragrans and Chionanthus retusus derived SSRs in diverse Osmanthus taxa, (2) quantify the influence of locus-specific factors on cross-transferability, and (3) determine the genetic relationships between accessions. We tested 70 SSR markers derived from O. fragrans and C. retusus in 24 accessions of Osmanthus. Sixty-seven markers showed transfer to at least one other Osmanthus species with an overall transfer rate of 84% of loci across taxa. Genotyping with 42 microsatellite markers yielded a total of 367 loci. Number of alleles per locus ranged from 2 to 17 with a mean of 8.7 ± 4.8. Mean observed and expected heterozygosities were 0.560 ± 0.225 and 0.688 ± 0.230, respectively. Percent of polymorphic loci ranged from 40% in Osmanthus delavayi to 100% in O. fragrans. Osmanthus fragrans had the highest mean number of alleles per locus (4.2) while O. delavayi had the lowest (1.1). A reduced suite of eight-markers can distinguish between accessions with non-exclusion probabilities of identity from 3.91E?04 to 2.90E?07. The SSR markers described herein will be immediately useful to characterize germplasm, identify hybrids, and aid in understanding the level of genetic diversity and relationships within the cultivated germplasm.  相似文献   

15.
Spider plant (Gynandropsis gynandra) is a traditional leafy vegetable widespread in sub-Saharan Africa and tropical Asia that is also valued for its medicinal properties. Developing a breeding program for the species requires detailed knowledge of its phenology, floral morphology and pollination system. This study investigates the effects of floral morphology and pollination mechanisms on the reproductive success in G. gynandra. The experiments were conducted in two locations in Benin. A split-plot design was used with four randomized complete blocks. Three accessions were randomly assigned to the whole plots and five treatments including natural self-pollination, hand self-pollination, geitonogamy, open pollination and hand cross-pollination were randomized over the sub-plots. We observed that individual plant exhibited 70% of staminate (male) flowers and 30% of hermaphrodite flowers. G. gynandra was andromonoecious. Open pollination and hand cross-pollination led to higher fruit and seed set. Natural self-pollination and hand self-pollination resulted in lower fruit and seed production. G. gynandra is a self-compatible and predominantly out-crossing species. Cross-pollination resulted in a significant increase in fruit set. This study set the ground for the development of improved cultivars in G. gynandra.  相似文献   

16.
Diversity and structure of populations may differ substantially between morphological traits and molecular markers. Explanations of such discrepancies are crucial for further progress in breeding as well as for the maintenance of genetic resources. Our objective was to compare indices of among-cultivars differentiation for morphological traits (QST) and molecular markers (FST) in alfalfa (Medicago sativa), a legume forage species. Ten cultivars representing the Northern and Southern types commonly grown in Europe were investigated. For each cultivar, 40 genotypes were analysed with 16 SSR markers and four morphological traits measured in two locations and several cuts. QST values were in general high (0.02–0.39) compared to the differentiation observed with molecular markers (FST = 0.01), especially for growth habit, indicating that morphological traits were more efficient to structure the diversity than molecular markers. For morphological traits, a clear separation of Northern and Southern cultivars was observed, whereas for molecular markers, no clear structure was detected. Nevertheless, the grazing type cultivar Luzelle was separated from the rest of the cultivars for both morphological traits and molecular markers. Although pairwise differences between cultivars were significant for both morphological traits and molecular markers, the main part of the variation was found within cultivars. This large within-cultivar variation may be explained, besides the outcrossing reproductive mode and autotetraploid genetics, by the recent history of M. sativa domestication in Europe and the frequent seed exchanges. Selection for morphological traits (QST > FST) was achieved without modification of within-cultivar neutral diversity.  相似文献   

17.
The present study investigated genetic diversity, structure and hybridization in a collection of the endangered wild pear species Pyrus pyraster (L.) Burgd. A total of 278 putative ‘true type’ P. pyraster trees originating from seven populations in the federal state of Saxony in Germany were analyzed along with 35 pear cultivars commonly cultivated in Saxony. The genetic analysis was performed using nine nuclear microsatellite markers (ncSSR) and two paternally inherited chloroplast marker (cpDNA) amplifying in the intergenic spacer region trnQ–rps16 and the intron region rps16. On basis of the ncSSR dataset after STRUCTURE analysis 80 % of the wild pear individuals were assigned as ‘true type’ P. pyraster genotypes. The cpDNA analysis showed shared haplotypes in P. pyraster and P. communis but with an unequal frequency in both species. The analysis of molecular variance resulted in a moderate (ncSSR) and great (cpDNA) variation among ‘true type’ P. pyraster and the pear cultivars. The genetic diversity in the ‘true type’ P. pyraster populations was still high and the genetic structure between the populations low (ncSSR and cpDNA) indicating a genetic exchange between the populations by pollen and seeds. The clear discrimination between the P. pyraster and P. communis confirms our expectation of the existence of ‘true type’ P. pyraster individuals in the study area. The existing genetic integrity and the high genetic diversity argue for the implementation of preservation measures in P. pyraster.  相似文献   

18.

Purpose

Eucalyptus forest plantations are normally devoid of understory vegetation that is often assumed to be associated with Eucalyptus allelopathic effects. The objective of this study was to determine the influence of high soil compaction and low soil moisture content on inhibition of the germination of understory seeds in Eucalyptus forests and thus would result in the scarcity of understory vegetation.

Materials and methods

The soil water content above the depth of 1 m of six major understory vegetation types was analyzed to determine if there was a correlation between soil water content and understory vegetation. The effects of soil treatment (soil-loosening vs. no soil-loosening) and water supply amount (2500, 2000, 1500, 1000, 500, 250, or 0 ml of water per day) on the seed germination rate of Stylosanthes sp. were explored using an artificial climate chamber experiment. Influence of soil source (five Eucalyptus forest soils vs. two non-Eucalyptus forest soils) and water supply (0, 50, 150, 200, or 400 ml of water every day) on the germination rate of five types of seed were assessed using a three-factor analysis of variance (ANOVA).

Results and discussion

Soil-loosening and water supply significantly (P?<?0.05) increased seed germination rate with the contribution rates of 26.14 and 42.93 %, respectively. Analysis of variance for three-factor experiments revealed a significant (P?<?0.05) effect of water supply and vegetation seed type on the germination rate of plant seeds. No significant effect of soil type was observed on germination rate, indicating that germination rate was not affected by soils in Eucalyptus forest.

Conclusions

The conservation of soil characteristics, such as water content and compaction, during the development of a Eucalyptus forest plantation may be an effective strategy for encouraging the growth of understory vegetation. This study highlights the importance that in dry areas or areas prone to long-term drought, it would be preferable to retain native vegetation.
  相似文献   

19.
Iran is amongst the countries in the world widely known for cultivation of Prunus spp. (or stone fruits). It is both a centre of origin and diversity of the stone fruits. Numerous wild species as well as many cultivars and landraces of these fruit crops are important genetic resources today in Iran and can be used for improvement and breeding of scion and rootstock cultivars which are resistant to many biotic and abiotic stresses through modern genomics and genetic technologies. This paper discusses the distribution, ethno-botany, diversity and utilization of wild and domesticated genetic resources of stone fruits including almond (Prunus dulcis (Miller) D. A. Webb.), peach and nectarine (P. persica Batsch), European and Japanese plum (P. × domestica L., and P. salicina L., respectively), sweet and sour cherry (P. avium L., and P. cerasus L., respectively), and apricot (P. armeniaca L.), all of which are members of the Rosaceae family. The goal of this paper is to highlight the importance of Iran as a main contributor to the diversity of Prunus genetic resources in the world, as well as, present major achievements regarding identification, collection, evaluation, conservation and utilization of this valuable genetic resource in Iran.  相似文献   

20.
Cyclopia (honeybush) species are widely-used in the production of a South African herbal tea and are endemic to the fynbos region of the Western and Eastern Cape Provinces. Honeybush is still one of the orphan agriculture crops and recent breeding efforts by researchers are hampered by the lack of basic genetic information e.g. basic chromosome numbers and ploidy levels. This study determined nuclear DNA content and ploidy level of various genotypes of three Cyclopia species using flow cytometry and cytological counting of chromosomes. Nuclei analysis of young leaves of C. genistoides, C. longifolia and C. subternata were done using a flow cytometer, while root tip squashes were carried out in order to correlate flow cytometry results. Flow cytometry analysis indicated differences in the nuclear DNA content among and within species whilst the DNA ploidy level only differed among species. Cyclopia genistoides had a higher DNA ploidy level (≥?10C) and DNA content (10.63 pg) than C. longifolia (6.09 pg) and C. subternata (5.99 pg), with no differences observed between the ploidy level of the latter two species (6C). The inferred ploidy level from nuclear DNA content by flow cytometry was consistent in all 30 genotypes of C. longifolia, and 24 of the 25 C. subternata and in only four of the 15 C. genistoides studied genotypes. These findings are important in breeding new cultivars with desired horticultural traits, thus improving the commercial characteristics for the sustainable production of honeybush.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号