生物可降解地膜对马铃薯生长及水分利用效率的影响

为研究旱作条件下生物降解地膜对马铃薯生长及水分利用效率的影响,以‘紫花白’作为试验材料,设置裸地(CK)、聚乙烯塑料地膜、生物可降解A膜、玉米秸秆、生物可降解B膜5种覆盖材料来研究生物可降解地膜对马铃薯耕层土壤温度、土壤含水量以及产量的影响。结果表明,与传统裸地(CK)相比,聚乙烯塑料地膜、生物可降解A膜、玉米秸秆、生物可降解B膜4种覆盖材料处理下耕层土壤(0~ 25 cm)日平均温度提高2.02、1.67、1.40、1.47℃;各覆盖材料均可提高土壤含水量,聚乙烯塑料地膜、生物可降解A膜、玉米秸秆、生物可降解B膜覆盖耕层土壤(0~25 cm)平均含水量提高3.12%、2.00%、1.92%、2.48%;各覆盖材料较对照马铃薯块茎产量增加6.25%、21.18%、17.07%、31.71%。试验结果表明,生物可降解地膜覆盖可以提高土层的温度、土壤含水率以及马铃薯产量,在不同覆盖方式中,生物可降解B膜覆盖效果最好。     

不同膜上遮挡措施对旱地玉米土壤理化性状及产量的影响

针对西北雨养旱作地区玉米长期地膜覆盖下出现的植株早衰现象,从不改变地膜保水功能的角度出发,采取地膜玉米膜上遮挡降温覆盖措施,研究不同膜上遮挡措施下土壤温度变化及对玉米产量形成的影响,分析不同膜上遮挡措施下玉米耕层土壤物理化学性状变化,为解析普通地膜玉米生育后期早衰提供理论参考。试验以陕单609为材料,基于2年田间试验,对比分析普通地膜覆盖+膜上覆黑色遮阳网(A)、普通地膜覆盖+膜上覆盖秸秆(B)与普通地膜覆盖(C) 3种模式对农田土壤温度、土壤养分及玉米干物质量积累、产量和水肥利用效率的影响。结果表明:(1)在普通地膜覆盖的基础上添加遮挡物(黑色遮阳网、秸秆)可以有效降低土壤温度和紧实度,其中玉米生育前期降温效果最为明显。(2)与对照处理C相比,膜上遮挡降温处理A和处理B玉米生长后期土壤的有机质和全氮、全钾含量均增加,玉米肥料偏生产力分别提高7.24%和6.97%。(3)降温处理能够延缓玉米生长后期绿叶面积的衰减速率,提高植株干物质量的积累,增加玉米粒重。与处理C相比,降温处理A和处理B的2年平均玉米产量分别较普通地膜覆盖处理提高6.39%和5.93%,平均水分利用效率分别提高8.17%和7.67%。在西北雨养旱作区,适当降低普通地膜玉米的膜下温度有助于改善土壤理化性状,促进玉米籽粒干物质积累和产量形成,提高肥水利用效率。     

不同覆盖处理对土壤酶活性和土壤养分的影响

为了探索华北平原生物可降解地膜对土壤酶活性和土壤肥力的影响,以及为寻求更加环保的替代方式,解决地膜覆盖带来的"白色污染"问题.设置普通PE地膜覆盖(PM)、生物可降解地膜覆盖(BM)、秸秆覆盖(SM)3种不同覆盖处理,以裸地不覆盖(CK)作为对照,研究不同覆盖处理对春玉米农田土壤酶活性和土壤养分含量的影响.试验结果表明:3种不同覆盖处理对于土壤过氧化氢酶和脲酶活性的影响在春玉米生育期内变化趋势大致相同,呈现先减小后增大再减小趋势,而土壤纤维素酶活性在生育期内先减小后增大.在春玉米收获期,2种不同覆膜处理均能提高上述3种酶活性,秸秆覆盖只对土壤过氧化氢酶、脲酶活性有提高作用.其中,对于土壤脲酶活性各个覆盖处理的提升效果明显,在0～10 cm和10～20 cm土层分别较CK处理提高了58.73％,33.65％,83.84％和26.19％,50.98％,61.21％.与CK相比,各个覆盖处理都提高了表层0～10 cm土层内的土壤有机碳、碱解氮、速效钾含量,且以秸秆覆盖效果最优,分别显著提高了24.68％,11.10％,23.34％,而2个覆膜处理之间无显著性差异;对于土壤有效磷含量,各个覆盖处理没有显著的提高作用.综上所述,在华北平原地区覆盖生物可降解地膜对于上述3种土壤酶活性和土壤养分含量的影响与覆盖普通PE地膜的效果相似.因此,生物可降解地膜代替普通PE地膜覆盖到农田当中解决"白色污染"问题具有良好的应用前景.     

可降解地膜降解性能及对棉花生长的影响

为了解决棉田使用PE地膜导致土壤污染问题,探讨可降解地膜的降解性能及对土壤水分、温度和棉花生长的影响。进行了3种可降解(氧化-生物降解)地膜、普通地膜和露地栽培棉花对比试验,设置5个处理,3次重复。结果表明:3种可降解地膜降解速率及强度不同,当季质量损失率达26.06%~79.96%,降解效果明显;降解诱导期相差15 d左右,具有一定可控性,降解后地膜残片变薄、变脆并紧贴地面,继续起到一定的增温、保墒作用。棉花地膜覆盖与露地栽培相比,播种后50 d内日平均地温提高2~3℃,单株结铃增加1.3个,铃重增加0.7 g,籽棉产量增加583.5 kg/hm2,达显著水平。可降解地膜覆盖与PE地膜覆盖栽培相比,对土壤温度、水分的影响差异不显著,籽棉产量无显著差异。以氧化-生物双降解地膜替代普通地膜应用于棉花覆盖栽培具有可行性。     

不同覆膜处理对土壤水分温度及春玉米产量的影响

为了研究可降解地膜的农用特性以及对不同种可降解地膜进行择优,试验通过对比研究的方法,对一般大田条件下普通地膜,不同可降解地膜以及露地栽培条件下土壤的温度、水分以及产量性状进行了对比研究。结果表明：在玉米生育前期,各地膜组均可以有效提高地下0~40 cm土壤水分含量,地下5~25 cm土壤温度,保温作用持续65天,其保水保温作用均表现为普通地膜与可降解地膜1差异不大,可降解地膜2次之,露地处理最差。普通地膜、可降解地膜1、可降解地膜2玉米增产率分别为19.5%,22.0%和13.1%,说明可降解地膜1和普通地膜对玉米产量影响显著且差异不大。由此可得,可降解地膜1代替普通地膜从事农业活动具有实际可操作性。     

不同类型地膜降解特征及其对马铃薯产量的影响

为探究不同类型降解地膜的降解特征及其对土壤温度、水分和马铃薯产量的影响,在即墨市蔬菜科技示范园进行了不同类型降解地膜覆盖马铃薯栽培试验。结果表明:全生物可降解膜的降解效果较好,0.006、0.008、0.010 mm的全生物可降解膜在收获前的降解程度已分别达到5级、4级和3级,而普通PE地膜降解效果只达到了1级。全生物可降解膜有较好的增温保墒作用,但增温保墒性能较PE膜差。对不同地膜覆盖的地块进行马铃薯产量测定,0.006、0.008、0.010 mm全生物可降解膜及PE膜与未覆盖地膜相比,分别增产12.9%、33.3%、33.6%、14.9%。试验结果表明:全生物可降解膜覆盖可以提高土壤温度和马铃薯产量,且自身降解程度较快,无需再增加人工清理费用,对环境的污染较小。综合考虑不同厚度全生物可降解地膜的价格等因素,0.008 mm厚度全生物可降解地膜更适合青岛地区马铃薯生产使用,对马铃薯有明显增产作用,同时也为残膜污染治理提供替代产品,有利于控制农业面源污染。     

不同类型地膜的降解特征及其对马铃薯产量的影响

为探究不同类型降解地膜的降解特征及其对土壤温度、水分和马铃薯产量的影响，在即墨市蔬菜科技示范园进行了不同类型降解地膜覆盖马铃薯栽培试验。结果表明：全生物可降解膜的降解效果较好，0.006 mm，0.008 mm，0.010 mm的全生物可 降解膜在收获前的降解程度已分别达到5级，4级和3级，而普通PE地膜降解效果只达到了1级。全生物可降解膜有较好的增温保墒作用，但增温保墒性能较PE膜差。对不同地膜覆盖的地块进行马铃薯产量测定，0.006 mm，0.008 mm，0.010 mm全生物可降解膜及PE膜与未覆盖地膜相比，分别增产12.9%、33.3%、33.6%、14.9%。试验结果表明：全生物可降解膜覆盖可以提高土壤温度和马铃薯产量，且自身降解程度较快，无需再增加人工清理费用，对环境的污染较小。综合考虑不同厚度全生物可降解地膜的价格等因素，0.008mm厚度全生物可降解地膜更适合青岛地区马铃薯生产使用，对马铃薯有明显增产作用，同时也为残膜污染治理提供替代产品，有利于控制农业面源污染。     

不同生物降解地膜对花生光合特性和产量的影响

为探讨生物降解地膜的控温控水效应及对花生生长发育和产量的影响, 进行了 4种全生物降解地膜、 普通地膜与不覆盖地膜的对比试验。结果表明： 地膜覆盖均优于不覆膜处理。生物降解地膜 Q2降解速度过快, 其他生物降解地膜降解期适宜。生物降解地膜 Q3更利于花生的光合特性和产量的形成, 效果优于普通地膜; Q4 与普通地膜相近, 效果略差于普通地膜; Q1、 Q2 2 种地膜效果差于普通地膜。生物降解地膜降解期适中, 能达到与普通地膜相似的保温保墒效果, 在提高叶绿素含量, 叶片净光合速率, 延缓叶片衰老方面优于普通地膜处理。Q3、 Q4 2种生物降解地膜能满足花生不同生育期对土壤温度、 水分的需要, 前期增温保水, 后期降温增渗, 促进光合作用, 并且可以减少白色污染, 减轻对土壤性质的破坏, 生态效益和经济效益良好, 具有广阔的应用前景。     

不同覆盖材料对花生养分吸收和土壤养分变化的影响

针对花生种植使用普通地膜造成的环境污染问题,通过大田小区试验,对比了生物降解膜(BD)、普通地膜(PE)和不盖膜(CK)处理对花生不同生长时期的养分吸收、土壤的养分变化以及产量等方面的影响。结果表明：收获期PE和BD处理的产量分别为7098.09、6868.92 kg/hm ²,较CK处理显著增产25.85%和21.78%。PE和BD处理土壤中的碱解氮和有效磷含量均呈现出"先减少后增加"的趋势,而有效钾含量表现为逐步下降的趋势,苗期为最大值,此后逐渐最低。不同覆盖条件下,花生植株地上部分的养分吸收量逐步增加,花生各生长时期的氮、磷、钾累积吸收量均表现为PE>BD>CK。该试验从土壤营养和花生养分吸收利用方面展开研究,为生物降解膜应用于花生生产可行性提供了理论依据。     

可降解地膜覆盖对土壤水热及春玉米产量的影响

为探讨可降解地膜在晋东南地区玉米生产中的实际意义,从土壤保温性、土壤保水性、玉米生育进程与产量、田间降解等方面对3种地膜进行分析比较。结果显示：与不覆膜裸地相比,两种降解地膜能显著提高土壤温度和土壤水分,但效果稍逊于普通地膜,两种降解地膜之间差异不显著;地膜覆盖可显著加快玉米生育进程和增加玉米产量,降解地膜使生育期缩短4天,普通地膜使生育期缩短了9天,分别增产9.06%、9.72%、14.54%,普通地膜优于可降解地膜的促进效果,但普通地膜与降解地膜产量之间差异未达显著水平。在地膜降解方面,2种可降解地膜破裂启动期较为一致,发生于覆膜后约40～50天,可基本满足玉米苗期对温度、水分的需要; 覆膜 90～100天后可降解地膜从土壤表面基本消失。以上结果显示,供试的2种可降解地膜不仅具有显著的生物学效应和经济学效果,其降解特性也基本符合玉米生长对环境条件的要求,且较普通地膜既省工省时,并可降低环境污染,所以降解地膜替代普通地膜应用于晋东南玉米生产具有可行性。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...