Myrothecium verrucaria isolates and formulations as bioherbicide agents for kudzu

The fungus Myrothecium verrucaria (MV) has previously been shown to have potential as a bioherbicide for kudzu (Pueraria lobata) control. It has also been shown that MV wild-type (MV-wt) often forms sectors, when grown on various nutrient media. Experiments compared MV-wt and MV sector efficacy when grown on agar or on rice grains. In greenhouse evaluations of sectors, applied as foliar sprays in water or in other formulations (corn oil, surfactant, and corn oil plus surfactant) for efficacy against kudzu seedlings, some sectors possessed bioherbicidal activity equal that of MV-wt, but others exhibited lower activity. Without a dew period, aqueous formulations of MV-wt, a yellow sector, and a white sector provided zero control, but all three isolates were active without a dew period when formulated in corn oil, Silwet L-77 surfactant, and in surfactant plus corn oil. Generally, the yellow sector was less effective than the other two isolates in any formulations, and the MV-wt and white sector provided approximately 100% mortality of the test plants. Dew (10 h) increased weed control to 100, 33, and 65%, respectively, for MV-wt, the yellow sector and the white sector. All isolates provided nearly 100% control in the oil and surfactant formulations with a dew period compared to treatments receiving no dew. Soil incorporation studies were also performed to compare MV-wt efficacy of preparations grown on agar versus growth on rice grains. Higher efficacies (1.75-3.3-fold increase) were obtained from rice grain preparations compared to preparations grown on agar, when preparations were incorporated at several rates into soil prior to planting. Cell-free extracts of the MV-rice cultures were also phytotoxic to kudzu seedlings up to the eight- to 10-leaf growth stage. Thus, formulation, growth media, and the application method are important determinants in the efficacy of MV and MV sectors on kudzu seedlings.     

1-甲基环丙烯采后处理对樱桃番茄果实成熟过程的影响

研究了不同浓度(0、0.035、0.07和0.11μL/L)的乙烯受体竞争性抑制剂1-甲基环丙烯(1-MCP)采后处理对绿熟期樱桃番茄的乙烯合成、果实软化、果实色素(叶绿素、茄红素、β-胡萝卜素)含量消长的影响.0.07 μL/L及其以上浓度的1-MCP降低了前期乙烯合成,同时推迟了乙烯释放高峰,但0.035 μL/L浓度的1-MCP处理并不能抑制内源乙烯合成.1-MCP显著延迟了果实软化和叶绿素降解,但并不影响这两个过程的启动.茄红素合成的启动和积累均受到了1-MCP抑制,而1-MCP并不推迟β-胡萝卜素合成的启动,只抑制其积累.这些结果提示了乙烯调节成熟生理过程的不同机制.对于绿熟期的樱桃番茄,0.07～0.11μL/L的1-MCP是实用的有效处理浓度.1-MCP有效浓度可能用于了解果实的乙烯受体水平和乙烯敏感性.     

Ca2+对离体培养的番茄花柄脱落的影响以及脱落过程中离区内钙形态的变化

在自然条件下,Ca~(2 )对离体培养的番茄花柄脱落有抑制作用,而对经乙烯处理的则有显著的促进。无论是在自然还是乙烯条件下,未经任何处理的番茄花柄脱落过程中总钙与果胶酸钙含量下降,而水溶性钙含量升高,Ca~(2 )在不同程度上提高脱落过程中离区总钙、果胶酸钙和水溶性钙含量,尤其是在乙烯下的效果更显著,而经EGTA处理的则相反。     

Influence of nicotianamine and iron supply on formation and elongation of adventitious roots in hypocotyl cuttings of the tomato mutant 'chloronerva' (Lycopersicon esculentum)

The influence of nicotianamine (NA) on formation and elongation of adventitious roots in hypocotyls of de-rooted NA-less mutant seedlings of Lycopersicon esculentum Mill, was examined in relation to the iron supply [ferric N-N'-ethylenediaminedi-(2-hydroxyphenylacetate) (FEDDHA), ferric ethylenediaminetetracetate (FeEDTA), ferric N-(2-hydroxyethyl)-ethylenediaminetriacetate (FeHEDTA, Fe-citrate and FeCl₃] in the nutrient solution. The initiation of root primordia in hypocotyl cuttings was independent of NA and occurred with about the same frequency in both, mutant and wild-type. In the mutant the development of primordia to adventitious roots was blocked at all iron sources used, except FeEDTA. Addition of NA (5x 10⁻⁶ to 2 × 10⁻⁵ M ) to the rooting medium resulted in a fast growth of adventitious roots in mutant cuttings with all iron sources tested. Rooting of wild-type cuttings was independent from NA application and iron sources. We suppose that NA is involved in the intracellular transport of iron. Its function is possibly linked with chelation of ferrous iron in the cell.     

外源NO与蔗糖对盐胁迫下番茄(Lycopersicon esculentum Mill)幼苗氧化损伤的保护效应

选取长至6～8片真叶的健康番茄(Lycopersicon esculentum Mill)幼苗,分别进行蔗糖、硝普钠(sodium nitropresside, SNP, 作为外源NO供体)及其体积比例组合(1:1)处理;36h后施以NaCl胁迫,并分别于0h(胁迫前)、24h、48h和72h 取样,进行相关生理生化指标测定.具体5个实验处理如下:A. 蒸馏水(CK); B. 100 mmol/L NaCl;C. 0.1 mmol/L SNP 100 mmol/L NaCl;D. 0.1 mmol/L SNP 1.0mmol/L蔗糖 100 mmol/L NaCl; E. 1.0 mmol/L蔗糖 100 mmol/L NaCl.结果表明:与SNP和蔗糖单独处理相比,二者组合处理对缓解盐胁迫下番茄幼苗的氧化损伤存在正协同效应,主要表现在进一步增强了番茄幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)的活性;提高了脯氨酸(Pro)的含量,同时膜脂过氧化产物丙二醛(MDA)含量显著降低(P＜0.05).采用聚丙烯酰胺浓度梯度凝胶电泳对盐胁迫24 h和48 h材料的POD同功酶检测表明,当NaCl单独处理时,番茄幼苗叶片POD同功酶第V条带缺失,其它谱带酶量减少,抑制了POD同功酶的表达;SNP和蔗糖单独处理能够保护盐胁迫(24、48h)所导致的POD同功酶条带的完整;而组合处理既保证了POD同功酶条带的完整,又加强了酶量的表达.随着盐胁迫时间的延长,其氧化损伤程度愈烈,SNP和蔗糖组合处理能够更有效地缓解盐胁迫对番茄幼苗植株造成的氧化损伤.     

Genetic mapping and protein product diversity of the self-incompatibility locus in wild tomato (Lycopersicon peruvianum)

Phenotypic diversity of self-incompatibility (S) alleles within nine natural populations ofLycopersicon peruvianum was investigated. Only 7 incompatible responses were observed of a total of 276 unique combinations tested, on the basis of controlled pollinations, indicating the large number of alleles that exist within these populations. Molecular weight polymorphism for specific major stylar proteins observed on SDS-PAGE was also evident in two of the populations examined. Five proteins were shown to map to theS locus and to be associated with differentS alleles through controlled pollinations and segregation of the proteins. Two of theseS related proteins had been described previously in terms of spatial and temporal expression consistent with their involvement in self-incompatibility (Mauet al., Planta 169, 184–191, 1986). A mapping population derived from a fully compatible cross was used to establish linkage of theS locus to two DNA markers,CD15 andTG184, that lie on chromosome 1. The order of the markers and estimates of map distances are given.     

Genetic interactions in the control of flowering time and reproductive structure development in tomato (Solanum lycopersicum)

Different tomato (Solanum lycopersicum) mutants, affected in flowering time, reproductive structure or plant architecture, were crossed to produce double mutants in order to investigate gene interactions in flowering regulation in this autonomous species with a sympodial growth habit. The compound inflorescence: uniflora, uniflora: self pruning, uniflora: blind, and jointless: uniflora double mutants all produced solitary flowers like their uniflora parent, instead of inflorescences. All double mutants were late flowering. uniflora: blind and uniflora: self pruning had flowering times intermediate between those of their two parents. jointless: uniflora and compound inflorescence: uniflora flowered later than uniflora, the mutant with the most delayed flowering. All double mutants developed strong lateral shoots at node levels approximately corresponding to the level at which their parent cultivars initiated their first reproductive structure, which is a typical trait of uniflora. These results suggest that the UNIFLORA gene acts upstream of the other investigated genes in controlling flowering in tomato, and that floral transition of the primary shoot and floral transition of sympodial segments are regulated differently.     

The significance of the magnesium to manganese ratio in plant tissues for growth and alleviation of manganese toxicity in tomato (Lycopersicon esculentum) and wheat (Triticum aestivum) plants

Results are reported for tomato (Lycopersicon esculentum L. var. Ailsa craig) and wheat (Triticum aestivum L. cv. Mara) which demonstrate that increasing concentrations of Mg in the plant raises plant tolerance to Mn toxicity.Water culture experiments with tomato show that under conditions of high Mn supply (200 µM, Mn), not only does increasing Mg application (0.75 mM to 15 mM) depress Mn uptake, but the higher Mg concentrations in the shoot counteract the onset of Mn toxicity when the concentrations of Mn in the shoot are also high. The ratio of Mg: Mn in the tissues is a better indicator of the appearance of toxicity symptoms than Mn concentration alone. Toxicity symptoms were observed when the Mg:Mn ratio in the shoot tissue was from 1.13 to a value between 3.53 and 6.54. The corresponding Mg: Mn ratio in the older leaves was from 0.82 to between 2.27 and 3.51.For wheat grown in soil, analyses of leaves revealed that growth could be expressed by the following relationship: Y=A+B exp(-kX), where Y=growth, X=Mg:Mn ratio, A, B and k=constants. Growth was significantly reduced when the Mg:Mn ratio fell below 20:1. From a measurement of this ratio it is therefore possible to predict the appearance of Mn toxicity and its influence on growth.