The induction of lincomycin resistance in Lycopersicon peruvianum and Lycopersicon esculentum

Lincomycin-resistant calli were induced from both Lycopersicon esculentum and Lycopersicon peruvianum using N-mitroso-N-methylurea (NMU) mutagenesis. From these calli lincomycin-resistant plants were regenerated. For L. peruvianum it was shown that the resistant plants could be divided in two classes with respect to their resistance to lincomycin and its derivative clindamycin. The first class comprised plants which were resistant to 500 mg/l lincomycin and showed no shoot or root formation in the presence of clindamycin; the second class consisted of plants resistant to 2000 mg/l lincomycin and these plants were able to form shoots and roots on clindamycin containing media. Lincomycin is an inhibitor of peptidyltransferase; chloroplast encoded parts of this enzymatic function are sensitive for this antibiotic. Reciprocal crosses between our lincomycin resistant and wild type L. peruvianum plants indicated a maternal inheritance of the mutation.     

Relationship between tomato fruit growth and fruit osmotic potential under salinity

To investigate the relationship between fruit growth and fruit osmotic potential (Ψ_s) in salty conditions, a sensitive tomato cultivar (Lycopersicon esculentum Mill.) and a tolerant accession of the wild species Lycopersicon pimpinellifolium Mill. were grown in a greenhouse with 0 and 70 mM NaCl, and the growth of the fruit studied from 15 to 70 days after anthesis (DAA). L. pimpinellifolium did not reduce significantly fruit weight in salty conditions throughout the growth period, whereas L. esculentum fruit weights decreased significantly with salinity from 45 DAA. L. esculentum fruit fresh weight reductions resulted from both less dry matter and water accumulation, although the fruit water content was affected by salinity before the fruit weight. In both species, fruit osmotic potential (Ψ_s) decreased significantly with salinity during the rapid fruit growth phase, although the changes were different. Thus, fruits from L. pimpinellifolium salt treated plants showed a Ψ_s reduction at the beginning (15 DAA) twice as high as that found in L. esculentum. As the advanced growth stage (from 15 to 55 DAA), the Ψ_s reduction percentages induced by salinity were quite similar in L. pimpinellifolium fruits, while increased in L. esculentum. Under saline conditions, the solutes contributing to reduce the fruit Ψ_s during the first 55 DAA were the inorganic solutes in both species, while in the ripe fruits they were hexoses. L. esculentum fruits accumulated K⁺ as the main osmoticum in salty conditions, while L. pimpinellifolium fruits were able to use not only K⁺ but also the Na⁺ provided by the salt.     

Antioxidants and antioxidative enzymes in wild-type and transgenic Lycopersicon genotypes of different chilling tolerance

The Mehler–Ascorbate–Peroxidase cycle is a protection system against reactive oxygen species (ROS) occurring during over-excitation of the photosynthetic apparatus. In the cultivated tomato, Lycopersicon esculentum, long-term chilling under moderate light leads to oxidation of the Calvin cycle key enzyme, ribulose-1,5-bisphosphate carboxylase (rubisco), presumably by generation of ROS. In contrast, high-altitude lines of the wild tomato species L. peruvianum were tolerant against the same chilling stress. In the present study, we analysed leaf contents of antioxidants (ascorbate, glutathione) and activities of enzymes of the Mehler–Ascorbate–Peroxidase cycle in the two Lycopersicon species. While antioxidant levels and activities of chloroplast superoxide dismutase (SOD) and ascorbate peroxidase (APX), both inducible by chilling stress, were similar in chilling-tolerant and chilling-sensitive genotypes, chilled L. esculentum showed lower glutathione reductase (GR) activities than high-altitude L. peruvianum. We constructed transgenic plants overexpressing an Escherichia coli GR in the chloroplast (approximately 60-fold of the wild-type (WT) activity). However, these plants resembled identical chilling sensitivity of the photosynthetic apparatus as WT plants as measured after a photoinhibition treatment and by the effect of long-term chilling on rubisco activity. We conclude that the Mehler–Ascorbate–Peroxidase cycle is not the limiting factor for the sensitivity of the photosynthetic apparatus of L. esculentum towards long-term chilling under moderate light. We suggest that a possible cause for the higher chilling tolerance of L. peruvianum is prevention of ROS formation by better conversion of light energy to photochemistry at suboptimal temperatures.     

Selection and characterization of somatic hybrids between Lycopersicon esculentum and Lycopersicon peruvianum

Somatic hybrids of the cultivated tomato, Lycopersicon esculentum, and a wild species, L. peruvianum, were obtained by fusion of leaf protoplasts from both species in the presence of poly-ethylene-glycol (PEG) or in an electric field. The somatic hybrids were selected on the basis of kanamycin resistance of L. esculentum and the plant regeneration capacity of L. peruvainum. Chromosome counts in root tips and the determination of the number of chloroplasts in guard cell pairs revealed that the majority of these hybrids was tetraploid (2n = 4x = 48). The remaining hybrids were at the hexaploid level with chromosome numbers between 64 and 72. The hybrid nature of the regenerated plants was confirmed by analysis of isozyme markers and by their morphology. Most hybrids did flower and set fruits and seeds after selfing. According to RFLP analysis 6 out of the 10 hexaploid hybrids contained two genomes of L. esculentum and four genomes of L. peruvianum. One of these hexaploids had genomes of two different L. peruvianum genotypes and was therefore considered to be derived from a triple protoplast fusion. The hexaploid plants were less fertile than the tetraploids and more resembled L. peruvianum.     

Cloning of tomato nuclear ribosomal DNA. rDNA organization in leaves and suspension-cultured cells

The rDNA fragments of EcoRI digested tomato nuclear DNA were detected by cross-hybridization with cloned Aspergillus nidulans rDNA. Two fragments coding for 18S and 25S rRNA, respectively were cloned and characterized. They were used to study structural organization of rRNA genes of a tomato cell suspension culture by hybridization with specifically cleaved nuclear DNA. The repeating units found were variable in restriction sites and in size with a basic unit of 8.6 kbp. Additionally, the analysis clearly demonstrates that nuclear DNA isolated from tomato leaves (Lycopersicon esculentum cv. Lukullus) and cultured cells derived therefrom bear significant differences in the structural organization of their ribosomal DNA.     

Both action potentials and variation potentials induce proteinase inhibitor gene expression in tomato

Tomato plants (Lycopersicon esculentum) accumulate proteinase inhibitor 2 (pin2) mRNA in response to insect attack, crushing and flaming in leaves distant from those treated. Most earlier work suggests that the systemic wound signals are chemical; here we try to determine whether electrical or physical (hydraulic) signals can also evoke pin expression. We used a mild flame to evoke a systemic hydraulic signal and its local electrical aftermath, the variation potential (VP), and we used an electric stimulus to evoke a systemic electrical signal, the action potential (AP). We determined the kinetic parameters of both the VP and AP. Flame-wounded plants essentially always exhibited major electrical responses throughout the plant and a several-fold increase in pin2 mRNA within 1 h. Electrically stimulated plants that generated and transmitted a signal (AP) into the analyzed leaf exhibited similarly large, rapid increases in pin2 mRNA levels. Plants which generated no signal, or signals of just a few microvolts, had unchanged levels of pin2 mRNA. Since the AP and VP both arrived in the receiving leaf before accumulation of pin2 mRNA began, we conclude that, in addition to the previously shown chemical signals, both hydraulically induced VPs and electrically induced APs are capable of evoking pin2 gene expression.     

基于线粒体COI基因的海蜇不同地理群体遗传特征

对采自辽东湾和韩国江华岛的2个海蜇群体56个个体的线粒体COI基因序列进行扩增,并结合GenBank上其他15个海蜇样品的同源序列对其进行序列变异分析,研究海蜇群体的遗传特征和群体遗传结构状况.在所分析的71个个体中共检测到28个多态位点,定义了32种单倍型.海蜇群体呈现出高的单倍型多样性(0.91±0.06～0.94±0.01)和中等或较低的核苷酸多样性[(0.60±0.34)%～(0.68±0.40)%].与其他几种大型水母相比,海蜇群体的遗传多样性水平较高.系统分析结果显示,海蜇群体间具有2个明显的单倍型谱系分支.比较海蜇不同群体间的遗传分化指数(F_ST)和分子变异分析(AMOVA)发现,在本研究取样范围内不同海蜇群体间存在明显的遗传结构.不同海蜇群体存在复杂的遗传模式,海蜇独特的生活史特征、其分布海域的海流状况及人为因素如增殖放流等可能是造成海蜇这种复杂遗传模式的原因.     

不同干旱水平下蚯蚓对番茄抗旱能力的影响

土壤无脊椎动物可能会通过促进土壤持水能力和增加土壤肥力而缓解植物的干旱胁迫。本研究采用蚯蚓和干旱水平的双因子完全交互设计, 模拟了干旱胁迫条件下蚯蚓对土壤性质及番茄抗旱性的影响。结果表明, 在高干旱胁迫时, 蚯蚓通过增加番茄茎叶抗氧化能力提高了植物抗旱性, 上调番茄茎叶脱落酸和茉莉酸生物合成过程的基因表达(NCED、NSY、OPR、AOS和LOX), 促进脱落酸和茉莉酸含量分别增加43.2%和33.6%, 过氧化氢酶、过氧化物酶和超氧化物歧化酶含量分别增加12.9%、8.4%和47.3%。在低干旱胁迫时, 蚯蚓上调茉莉酸合成通路基因表达, 但降低了脱落酸含量, 对转录因子ABF4、MYC2基因表达和植物抗氧化能力无明显影响。干旱导致的土壤水分和养分条件变化影响着蚯蚓介导的植物抗旱性响应。本研究证明了土壤动物对植物抗旱的重要作用, 如蚯蚓对植物激素合成、信号传导和抗氧化能力的影响。了解土壤动物影响植物抗旱的内在机制, 有助于深挖和利用土壤动物的多样化生态功能。     

Temporal and ontogenetic aspects of protein induction in foliage of the tomato, Lycopersicon esculentum

Damage to foliage of the tomato, Lycopersicon esculentum, causes the induction of proteinase inhibitors and of the oxidative enzymes polyphenol oxidase, peroxidase, and lipoxygenase. The time courses of induction of these proteins by feeding of two caterpillar species (Manduca sexta and Helicoverpa zea) were studied in a series of experiments. In another series of experiments, the effects of plant age on the inducibility of these proteins were studied. In the time course experiments, induction of proteinase inhibitors and oxidative enzymes in the damaged leaflet was rapid, with higher protein activities evident in damaged leaflets within 12–24 h of damage, depending on the enzyme and the species of insect used to damage the plant. Systemic induction of proteinase inhibitors was also rapid, but systemic induction of polyphenol oxidase was delayed relative to systemic induction of proteinase inhibitors, possibly because high constitutive polyphenol oxidase activities obscured expression of systemic induction at earlier time points. Lipoxygenase and peroxidase were not induced systemically. Induction of all proteins persisted for at least 21 days. In the phenology experiments, inducibility of all proteins decreased in magnitude and was less consistent as plants aged. The results of these experiments exemplify the numerous constraints on induction in tomato plants. Knowledge of these physiological constraints is important to an understanding of the ecological role and causal basis of induced resistance.     

Temperature dependence of the germination of tomato seeds

1. 1.|The germination of tomato “C38” seeds exposed to periodical white incandescent light occurs from 6.0° ± 0.2°C to 37.5° ± 0.2°C, being rate-limited for 10.3° T 25.9°C, and elsewhere limited by the germination capacity.

2. 2.|Rate averages are linearly T-dependent outside their optimum range (25.9° T 29.5°C) and rate variances are typically heterogeneous.

3. 3.|The smooth curvilinear Arrhenius plot indicates that diffusion processes cannot be rate-limiting outside the interval 25.9° T 29.5°C, whereas phase transitions and (or) transconformation of proteins may limit the rate above 34.9°C and, by opposite effects, below 15.3°C.

4. 4.|The thermal communication between the environment and the germinating seed proceeds by a temperature signal which is quenched by random thermal noise at T 11.2°C and at T 34.0°C.

Staining Tomato Fruit Cuticle and Exocarp Tissues

Immature fruit of tomato, Lycopersicon esculentum (Celebrity), was examined to observe the cuticle, its interface with the epidermis, and the general histology of the outer exocarp. Paraffin sections were stained first with Bismarck brown Y. Structures already stained in various hues of brown were stained again with either azure B, aluminum hematoxylin and alcian blue 8GX, or the periodic acid-Schiff (PAS) reaction. Bismarck brown-azure B displayed the cuticle in strong contrast with subjacent tissue; however, nuclei were not easily identified at low magnification. Bismarck brown-hematoxylinalcian blue produced a sharply contrasted combination of yellow cuticle, bright blue cell walls and purple nuclei. Nuclei stained purple with hematoxylin were easily identified at × 100. Bismarck brown-PAS stained the cuticle golden brown and subjacent tissues magenta red. Surprisingly, epidermal cells stained specifically and intensely with PAS while pretreatment with an aldehyde blockade and omission of periodic acid prevented staining of all other tissues.     

Germination ecology of three endangered river corridor plants in relation to their preferred occurrence

As a contribution to conservation, we investigated germination requirements of three perennial, endangered river corridor plants of Central European lowlands coexisting in subcontinental flood meadows, but preferring particular zones of decreasing flooding frequency and duration along the elevational gradient of the banks. It was hypothesized that the species have specific germination requirements to respond successfully to open patch creation depending on their occurrence along the gradient of spring flooding in the field. This study involved controlled experiments and phenological studies.     

基于ITS和ndhF-rpl32序列的荞麦种间亲缘关系分析

荞麦起源于我国, 演化形成了丰富的物种和遗传多样性。为了有效研究和利用荞麦及其野生种资源, 以从四川、甘肃、贵州等地采集的荞麦属(Fagopyrum)10个种(含变种、亚种和复合体种)共71份材料为对象, 通过ITS和叶绿体ndhF-rpl32序列分析, 利用MEGA5.0构建系统进化树, 探讨了荞麦种内及种间亲缘关系。结果表明, 在ITS序列矩阵中, 序列长度为725 bp, 信息位点为150个, 占序列总长度的20.7%; 在ndhF-rpl32序列矩阵中, 序列长度为940 bp, 信息位点为158个, 占序列总长度的16.8%。由ITS序列和ndhF-rpl32序列构建的两个进化树都可以将71份材料分为大粒荞麦种组和小粒荞麦种组; 其中, 大粒荞麦种组包括栽培苦荞和米苦荞(F. tataricum)、金荞复合体(F. cymosum complex)、栽培甜荞(F. esculentum)和野生甜荞(F. esculentum ssp. ancestralis); 小粒荞麦种组包括齿翅野荞(F. gracilipes var. odontopterum)、疏穗小野荞(F. leptopodum var. grossii)、小野荞(F. leptopodum)、密毛野荞(F. densovillosum)、细柄野荞(F. gracilipes)和硬枝万年荞(F. urophyllum)。而ndhF-rpl32序列构建的系统发育树还能区分栽培甜荞和野生甜荞, 具有更好的聚类效果。另外, 与栽培甜荞相比, 金荞复合体与栽培苦荞的亲缘关系更近。该研究为荞麦属种的分类和条形码研究提供了一定的科学依据。     

海南杜鹃在河岸带弯道两侧的空间分布格局和年龄结构差异

河岸带是河流与陆地生态系统的交错带, 孕育了丰富的生物多样性。河流的冲刷与地势的作用使得河岸带往往形成弯道, 弯道内外两侧水流速度、泥沙性质与植物繁殖体聚集程度不同, 影响到植物生长与种群动态, 可能导致河岸带弯道凸岸、凹岸两侧植物空间分布格局和种群结构存在较大差异。该研究以中国特有、狭域分布的海南杜鹃(Rhododendron hainanense)为例, 揭示溪流弯道对其两侧海南杜鹃种群空间分布格局与种群动态的影响。在海南岛3个国家级自然保护区内各设置2个河岸弯道样带, 用方差/平均值法对弯道凸岸、凹岸两侧海南杜鹃的空间分布格局和种群动态进行对比研究。结果显示: (1)海南杜鹃弯道凸岸的种群结构呈增长型, 凹岸基本呈衰退型; (2)凸岸一侧上下游的海南杜鹃种群基本呈增长型, 凹岸一侧上下游的海南杜鹃则出现断龄现象; (3)距离弯顶位置或河岸越远, 各龄级海南杜鹃种群个体数量基本呈下降趋势; (4)在2 m × 2 m尺度下, 弯道凸岸及其下游的海南杜鹃主要呈聚集分布, 上游近似随机分布, 凹岸及其上下游则均呈随机分布。海南杜鹃分布的山区河岸带水流较快、坡度较大, 可能是导致弯道凹岸个体较少、种群结构呈衰退型的主要原因。因此, 河岸弯道内外两侧可能存在个体生长与群体差异, 在开展河岸带植物种群动态与物种保育研究中需给予重视。     

Difference in spatial distribution patterns and population structures of Rhododendron hainanense between both sides of riparian bends

河岸带是河流与陆地生态系统的交错带, 孕育了丰富的生物多样性。河流的冲刷与地势的作用使得河岸带往往形成弯道, 弯道内外两侧水流速度、泥沙性质与植物繁殖体聚集程度不同, 影响到植物生长与种群动态, 可能导致河岸带弯道凸岸、凹岸两侧植物空间分布格局和种群结构存在较大差异。该研究以中国特有、狭域分布的海南杜鹃(Rhododendron hainanense)为例, 揭示溪流弯道对其两侧海南杜鹃种群空间分布格局与种群动态的影响。在海南岛3个国家级自然保护区内各设置2个河岸弯道样带, 用方差/平均值法对弯道凸岸、凹岸两侧海南杜鹃的空间分布格局和种群动态进行对比研究。结果显示: (1)海南杜鹃弯道凸岸的种群结构呈增长型, 凹岸基本呈衰退型; (2)凸岸一侧上下游的海南杜鹃种群基本呈增长型, 凹岸一侧上下游的海南杜鹃则出现断龄现象; (3)距离弯顶位置或河岸越远, 各龄级海南杜鹃种群个体数量基本呈下降趋势; (4)在2 m × 2 m尺度下, 弯道凸岸及其下游的海南杜鹃主要呈聚集分布, 上游近似随机分布, 凹岸及其上下游则均呈随机分布。海南杜鹃分布的山区河岸带水流较快、坡度较大, 可能是导致弯道凹岸个体较少、种群结构呈衰退型的主要原因。因此, 河岸弯道内外两侧可能存在个体生长与群体差异, 在开展河岸带植物种群动态与物种保育研究中需给予重视。     

Alternative soilless media for growing Petunia x hybrida and Impatiens wallerana: physical behavior, effect of fertilization and nitrate losses

The use of alternative soilless media for the production of potted plants requires knowledge of their physical and chemical characteristics to result in the best conditions for plant growth. We investigated the use of alternative soilless media based on river waste and Sphagnun sp. and Carex sp. from Argentinean peatlands on Petuniaxhybrida and Impatiens wallerana production at two fertilization levels (200 and 400mgl(-1)N). River waste or 'temperate peat' is the name given to a material, resulting from the accumulation of aquatic plant residues under an anaerobic subtropical environment, which is dredged from river banks. Our results showed that alternative substrates based on river waste can be used to grow high quality plants. This result was not fully explained on the basis of established methods to evaluate substrate quality. Highly concentrated fertigation solution decreased the substrate quality parameters and plant growth. Nitrate leaching from the alternative substrates containing river waste was lower than the standard peat-based materials, which makes river waste desirable from a sustainable pot production system perspective. River waste and Carex peat are suitable alternatives to Sphagnum peat from the Northern Hemisphere.     

番茄属(Lycopersicon)四个种的过氧化物酶同工酶分析

本文报告了应用连续浓度梯度聚丙烯酰胺凝胶电泳对番茄属Lyco-persicon的四个种:秘鲁番茄L.peruviaunm Mill.,多毛番茄L.hirsutum Humb.et Bonp,醋栗番茄L.pimpinellifolium(Jusl)Mill和普通番茄L.esculentum Mill.的86份材料,15个不同生育时期,不同器官以及同一器官的不同部位的过氧化物酶同工酶的分析结果。结果表明:L.Peruvianum的各个生育期和不同器官的过氧化物酶同工酶谱带叠加共有28条带,L.hirsutum有29条带,L.pimpinellifolium有28条带,L.esculentum有27条带。种间过氧化物酶同工酶谱型差异明显,种内不同生育期叠加总酶谱基本一致。在根、茎和叶中,这四个种的过氧化物酶同工酶酶谱和活性具有相似的生育期变化规律和器官分布规律.在果实发育过程中,种间过氧化物酶同工酶酶谱、活性及变化律规都不相同。本文还就同工酶谱型相似值的意义,野生资源及同工酶分析技术在番茄育种中的应用等问题进行了讨论。     

黄河流域湿地水鸟多样性保护对策

黄河是中华文明的发源地, 被誉为母亲河, 是两岸社会经济发展的保障, 切实保护好黄河流域湿地生态系统, 事关中华民族伟大复兴的千秋大计。黄河流域湿地总面积为391万ha, 其中80.4%分布在上游, 中游和下游分别仅12.5%和7.1%。黄河流域是东亚-澳大利西亚候鸟迁徙路线和中亚候鸟迁徙路线上水鸟的关键栖息地, 一些迁徙水鸟最关键的栖息地均分布在黄河流域, 如黑颈鹤(Grus nigricollis)、白鹤(G. leucogeranus)、丹顶鹤(G. japonensis)、斑头雁(Anser indicus)、大鸨(Otis tarda)、东方白鹳(Ciconia boyciana)、大天鹅(Cygnus cygnus)、疣鼻天鹅(C. olor)、青头潜鸭(Aythya baeri)等。尽管黄河流域湿地提供的水资源仅占全国的2%, 但维持着全国12%的人口饮水安全和15%的耕地用水, 湿地生态系统的脆弱性较高。截至2017年底, 黄河流域已建立各类湿地自然保护地230处, 其中国家公园2处、国家级自然保护区9处、地方级自然保护区68处、国家湿地公园145处、省级湿地公园6处, 湿地保护率达到65%, 高于我国湿地保护53%的平均水平。然而, 流域尺度现有水鸟生物多样性保护仍然面临不少挑战, 包括全球气候变化、水资源过度利用、水环境污染、栖息地丧失等。为此, 我们提出了建立以国家公园为主体的湿地保护地体系、开展濒危候鸟栖息地修复和强化黄河流域综合管理的体制机制建设等建议。