农五师葡萄钾素动态变化及调节措施研究

通过叶分析研究了不同葡萄品种叶柄全钾5～9月含量动态变化规律.结果表明:葡萄叶柄钾含量在生育期内整体呈波浪式下降趋势,前期下降迅速,中期平缓,进入浆果成熟期后又趋于下降；强势品种在整个生长季节内对钾的吸收大于弱势品种；早熟品种叶柄内钾含量变化趋势比晚熟品种提前.根据新疆农五师葡萄园区土壤有效钾含量分布现状,建议生产中应根据葡萄钾元素动态变化特点,不同团场应结合当地土壤有效钾含量相应补充.     

高温胁迫下AM真菌对牡丹叶片解剖结构和蒸腾特性的影响

作者研究了高温胁迫下丛枝菌根(arbuscular mycorrhizal,AM)真菌对盆栽牡丹幼苗叶片解剖结构和蒸腾特性的影响。结果表明,供试AM真菌摩西球囊霉(Glomus mosseae)和地表球囊霉(Glomus versiforme)均能侵染牡丹根系,其侵染率分别为47%和44%。接种AM真菌的比未接种对照(CK)植株的叶片细胞排列紧密,叶片厚度、栅栏组织和海棉组织厚度均表现为接种G.mosseae植株>接种G.versiforme植株>CK。在相同高温下接种AM真菌处理的牡丹叶片蒸腾速率、气孔导度和气孔开度均显著低于CK。AM真菌提高了牡丹植株的抗热性,这对于高温胁迫下保持和提高光合效率是十分重要的。其中接种G.mosseae处理的效果优于G.versiforme     

Histological and proteomics analysis of apple defense responses to the development of Colletotrichum gloeosporioides on leaves

Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. is an important fungal pathogen known to cause glomerella leaf spot (GLS). The objective of this study was to analyze the infection of C. gloeosporioides on leaves of apple cv. Fuji (resistant) and cv. Gala (susceptible) and apply proteomics techniques to study the apple defense responses 48 h after inoculation (h.a.i.). On both of cultivars, C. gloeosporioides started to germinate at 3 h.a.i. on adaxial surface and produced appressoria adhering to epidermal cell juxtapositions. Histological analysis showed more stratified parenchyma in leaves of cv. Fuji than cv. Gala associated with differences in the chemical composition of cell walls. Total and unique proteins expressed by cvs. Fuji and Gala at 3, 12, 24 and 48 h.a.i. were detected by comparative proteomes analysis. A total of 42 unique proteins expressed at 24 and 48 h.a.i. were identified by MALDI/TOF mass spectrometry, and most of these proteins were identified as directly involved in defense responses.     

水稻半外卷叶突变体sol1的表型分析与基因定位

适度卷曲有利于提高水稻叶片的光合效率,增加植株光合产物的有效积累量。我们利用甲基磺酸乙酯(EMS)处理籼型水稻保持系西农1B,获得一个稳定遗传的水稻半外卷叶突变体。该突变体从十叶期开始各叶片逐渐向外卷曲直至半卷状,并伴随茎秆半矮化和叶片披垂,暂被命名为semi-outcurved leaf 1(sol1)。与野生型(WT)相比,sol1的叶片卷曲指数均达到30%以上(P<0.01);倒一、倒二、倒三、倒四节节间长度和穗长极显著缩短,倒一、倒二、倒三叶的叶夹角显著或极显著增加;有效穗数、千粒重、每穗实粒数、结实率显著或极显著下降,一次枝梗数则增加11.3%(P<0.05)。sol1的蒸腾速率、胞间CO2浓度、气孔导度显著高于野生型。石蜡切片显示,sol1倒一叶的泡状细胞体积变小,数量显著增多,表皮细胞体积略微增大。遗传分析表明,sol1的半外卷叶性状受1对隐性核基因调控,定位于6号染色体标记JY6-3和JY6-10之间165 kb的物理范围内,共含15个注释基因。qRT-PCR结果表明,与泡状细胞相关的内卷基因和外卷叶基因RL14、Roc5、REL1在突变体sol1中呈不同程度的上调,NRL、BRD1、OsHox32、ADL1、LC2则呈不同程度的下调。研究结果为SOL1基因的克隆和功能研究奠定了基础。     

南瓜银叶突变体48a的表型特征及其遗传学分析

南瓜银叶突变体48a是在嫩食型中国南瓜中分离筛选到的稳定遗传自交系,银色叶不仅可以作为标记性状应用到育种中,还可为南瓜抗虫、抗病、耐寒等一系列研究提供重要的材料基础。笔者对银叶突变体的表型特征及叶片的解剖结构进行鉴定分析,发现植株整体长势、熟性与野生型无明显差异;成熟叶片正面全部呈银灰色,叶绿素含量明显降低,叶片上表皮细胞与栅栏细胞间明显剥离,存在明显的空隙。利用突变体48a和野生型49a南瓜自交系构建的六世代遗传群体,调查发现F2的绿叶与银叶符合3∶1的分离比,回交群体BC1P1分离比符合1∶1,表明南瓜银色叶性状由单隐性基因控制。     

The mechanical roles of the clasping leaf sheath in cereals: Two case studies from oat and wheat plants

Stem lodging is a common problem in cereal crop production and a main constraint for grain yield improvement. The leaf sheath that surrounds and protects the hollow internodes of stem could provide the plants with a great physical support. However, this biomechanical function has been ignored for several decades in cereal crops. This study aimed to examine the biomechanical properties of basal stem internodes and lodging susceptibility of the whole plants with or without the clasping leaf sheath in wheat (Triticum aestivum L.) and oat (Avena sativa L.) among different genotypes and agronomic practices (including planting densities and nitrogen application rates). The main objective was to quantify the mechanical role of the leaf sheath in oat and wheat crops by a “safety factor” method. On average, the leaf sheath contributed 40%, 68% and 38% of the overall stem bending strength, flexural rigidity and safety factor, in oat, while it accounted for 11%, 24% and 10%, respectively, in wheat plants. The significant contribution of the leaf sheath is due to its vital role in enlarging the peripheral position (i.e., second moment of area) and stiffness (i.e., Young's modulus). The contribution ratios (%) were found to be higher in oat than in wheat plants, due to the greater mass density of leaf sheath and more proficient/prevailing stay-green capability in oat genotypes. This study emphasizes the important mechanical role of clasping leaf sheath on stem internodes of cereals and indicates that the stay-green trait of the leaf sheath can be exploited to design appropriate varieties with improved lodging resistance and great yield potential.     

Identification of a phytoplasma associated with pomegranate little leaf disease in Iran

During 2012–2014 surveys for the presence of phytoplasma diseases in Fars province (Iran), pomegranate little leaf symptoms were observed in several orchards in Khafr and Neyriz areas. Samples collected from symptomatic plants positively reacted in nested PCR assays using P1/P7 followed by R16F2n/R16R2 primer pairs producing the expected 1,250 bp DNA fragments. Real and virtual RFLP analysis showed that the sequences of phytoplasma strains from Khafr and Neyriz (KPLL and NPLL strains, respectively) were identical to each other and belong to 16SrII phytoplasma group, subgroup D. Phylogenetic analysis of the R16F2n⁄R16R2 DNA region confirmed that KPLL and NPLL phytoplasmas were enclosed in the same clade as other 16SrII-D subgroup phytoplasmas. This is the first reported occurrence of a 16SrII phytoplasma infecting pomegranate trees.     

东北“三大硬阔”叶片和叶轴质量分配比较

以3个树种健康复叶为试材,研究了叶内光合构件和支撑构件的生物量投资的种内种间变化规律。结果表明:水曲柳、胡桃楸和黄檗叶轴质量占复叶质量的比例分别为0.18、0.26和0.17,胡桃楸显著大于其它2个树种。跨物种尺度上,复叶大的树种需要更多的叶内支撑结构投资。但物种水平上,水曲柳叶片投资随叶增大而增大,胡桃楸则降低,黄檗基本稳定,表现出与跨物种水平上的叶片投资随叶增大而降低的普遍规律不同。今后需要加深物种水平上叶内生物量分配的异速生长的了解。     

Density responses and spatial distribution of cotton yield and yield components in jujube (Zizyphus jujube)/cotton (Gossypium hirsutum) agroforestry

Trees are the dominant species in agroforestry systems, profoundly affecting the performance of understory crops. Proximity to trees is a key factor in crop performance, but rather little information is available on the spatial distribution of yield and yield components of crop species under the influence of trees in agroforestry systems. Also, little information is available on how crop density may be exploited to optimize the yield in such systems. Here we studied the performance of cotton in jujube/cotton agroforestry. Field experiments were conducted in 2012 and 2013 in Hetian, Xinjiang, China. Cotton was grown at a row distance of 60 cm in three densities, 13.5, 18.0 and 22.5 plants m⁻² in six m wide paths between tree lines in a jujube plantation. Plant density affected both cotton aboveground dry matter and yield significantly. The highest yield was attained at the intermediate density of 18.0 plants m⁻² (20.0 plants m⁻² corresponding in sole cotton), lower than the optimal density in sole cotton (25.0 plants m⁻²). Yield at the lower density was constrained by the low number of bolls per m² as a direct consequence of the low density, whereas at the high plant density yield was constrained by a lower allocation of assimilates to cotton seed and lint, as a consequence of intraspecific and interspecific competitions. There were strong gradients in yield and yield components in relation to the distance from the tree rows. Leaf area and total dry matter of cotton in rows close to the tree lines were reduced, especially in the rows next to the trees. Moreover, biomass allocation to cotton fruits was reduced in these rows. Competitive influences from the trees on cotton performance extended two rows deep in a six-year old jujube stand, and even three rows deep in a seven-year old stand. Shading effects on cotton yield were compensated by increasing plant density as a result of greater boll numbers per unit ground area. Data from this study help guide the design of optimal plant density of cotton in jujube plantations and give insight in the spatial distribution and dynamics of competitive effects in agroforestry systems in general.