对TMV不同抗性番茄品种叶绿体DNA的RAPD分析

本实验对ＴＭＶ抗性和敏感的两个番茄品种ｃｔ－ＤＮＡ进行ＲＡＰＤ分析,结果发现在２０个引物中有４个引物的扩增产物存在明显差异,共显示出１４条差异带。这可能是由于ｃｔ－ＤＮＡ碱基顺序变异或小片段ＤＮＡ插入或缺失造成的,深入研究将对探讨番茄抗ＴＭＶ的分子机理,进而用遗传工程方法培育抗病品种具有重要意义。     

Chloroplast and mitochondrial DNA composition of triploid and tetraploid somatic hybrids between Lycopersicon esculentum and Solanum tuberosum

The chloroplast (cp) DNA type and mitochondrial (mt) DNA composition of 17 somatic hybrids between a cytoplasmic albino tomato and monoploid potato (A7-hybrids) and 18 somatic hybrids between a nitrate reductase-deficient tomato and monoploid potato (C7-hybrids) were analyzed. Thirteen A7-hybrids and 9 C7-hybrids were triploids (with one potato genome); the other hybrids were tetraploid. As expected, all A7-hybrids contained potato cpDNA. Of the C7-hybrids 7 had tomato cpDNA, 10 had potato cpDNA and 1 hybrid contained both tomato and potato cpDNA. The mtDNA composition of the hybrids was analyzed by hybridization of Southern blots with four mtDNA-specific probes. The mtDNAs in the hybrids had segregated independently from the cpDNAs. Nuclear DNA composition (i.e. one or two potato genomes) did not influence the chloroplast type in the C7-hybrids, nor the mtDNA composition of A7- or C7-hybrids. From the cosegregation of specific mtDNA fragments we inferred that both tomato and potato mtDNAs probably have a coxII gene closely linked to 18S+5S rRNA genes. In tomato, atpA, and in potato, atp6 seems to be linked to these mtDNA genes.     

Effects of aluminium on nitrate uptake and assimilation

A study was conducted to examine the hypothesis that the effects of external Al on NO₃^? uptake and assimilation depend upon the concentration of Al present. Young soybean seedlings [Glycine max (L.) Merrill, cv. Essex], growing under moderate acidity stress at pH 4-2, were exposed to a range of {A1³⁺} in solution for 3d, and to labelled 99 atom %¹⁵NO₃^? during the final hour of Al exposure. Uptake of ¹⁵NO₃^?g^?1 root dry weight was increased by about 28% in the presence of Al at {A1³⁺} below 10 mmolm^?3, and NO₃^? uptake was decreased by about 12% when the {A1³⁺} increased to 44mmoln^?3. The stimulation phase closely paralleled stimulation of root elongation. At higher {A1³⁺}, the inhibition of root elongation was much more severe than that of NO₃^? uptake. There was no indication of a separate effect of Al on root ¹⁵NO₃^? reduction in situ, as the accumulation of reduced ¹⁵N in the root remained a similar percentage of ¹⁵NO₃^? uptake at all {A1³⁺}. At higher {A1³⁺}, the atom %¹⁵N enrichment of the insoluble reduced-N (protein) fraction of root tips increased. This suggests that the Al inhibition of root elongation did not result from disruption of the N supply to the root apex.     

AtPLC2, a gene encoding phosphoinositide-specific phospholipase C,is constitutively expressed in vegetative and floral tissues in Arabidopsis thaliana

A cDNA encoding a phosphoinositide-specific phospholipase C (PI-PLC) from the higher plant Arabidopsis thaliana was cloned and characterized.The gene corresponding to this cDNA is designated AtPLC2. The overall structure of the predicted AtPLC2 protein is similar to those of plant PI-PLCs and mammalian -type PI-PLCs. Northern blot analysis revealed that AtPLC2 is expressed constitutively whereas AtPLC1S, another gene for PI-PLC of Arabidopsis, is induced by environmental stresses such as dehydration and salinity, indicating that the function of AtPLC2 is distinct from that of AtPLC1S. The AtPLC2 mRNA was detected in vegetative and floral tissues. We determined the positions of these two PI-PLCs genes on Arabidopsis chromosomes by RFLP mapping using P1 genomic clones.     

Interaction of Glomus mosseae and Paecilomyces lilacinus on Meloidogyne javanica of tomato

The effects of Glomus mosseae and Paecilomyces lilacinus on Meloidogyne javanica of tomato were tested in a greenhouse experiment. Chicken layer manure was used as a carrier substrate for the inoculum of P. lilacinus. The following parameters were used: gall index, average number of galls per root system, plant height, shoot and root weights. Inoculation of tomato plants with G. mosseae did not markedly increase the growth of infected plants with M. javanica. Inoculation of plants with G. mosseae and P. lilacinus together or separately resulted in similar shoots and plant heights. The highest root development was achieved when mycorrhizal plants were inoculated with P. lilacinus to control root-knot nematode. Inoculation of tomato plants with G. mosseae suppressed gall index and the average number of galls per root system by 52% and 66%, respectively, compared with seedlings inoculated with M. javanica alone. Biological control with both G. mosseae and P. lilacinus together or separately in the presence of layer manure completely inhibited root infection with M. javanica. Mycorrhizal colonization was not affected by the layer manure treatment or by root inoculation with P. lilacinus. Addition of layer manure had a beneficial effect on plant growth and reduced M. javanica infection.     

锌对番茄叶绿体亚显微结构的影响与光强度的关系(简报)

番茄植物缺锌时,茎尖停止生长,叶部和茎上出现褐色斑点,有明显的小叶病症状。此外,叶绿素含量减少,光合强度降低,叶绿体结构遭到破坏。陈保生和崔澂发现叶绿体含锌量显著降低,并提出缺锌阻碍了叶绿体的发育。Hoagland发现锌在植物中的生理作用与光有关,此后,不少人对植物需锌与光的关系进行了研究,证明植物在光下较暗中需锌较多。通过进一步研究,李佳格和崔澂证明锌对自养生长的绿色植物的作用与光有关,而对异养的非绿色植物的作用与光无关。Spencer还报道锌和光影响叶绿体希尔反应活性。由此看来,锌与叶绿体的结构和功能是密切相关的。但锌在     

Host Differences among Florida Populations of Belonolaimus longicaudatus Rau

Three populations of Belonolaimus longicaudatus from Gainesville, Fuller''s Crossing, and Sanford, all in Florida, were tested for parasitism on Citrus jambhiri (rough lemon), Arachis hypogaea (''Early Runner'' peanut), Fragaria sp. (''Florida 90'' hybrid strawberry), and Lycopersicon esculentum (''Rutgers'' tomato). The three populations were found to be three different physiological races because: (i) the Fuller''s Crossing population reproduced well on and caused injury to rough lemon and tomato but not strawberry; (ii) the Gainesville population reproduced well on and caused injury to peanut, strawberry and tomato but not on rough lemon; (iii) the Sanford population reproduced well on and caused injury to peanut, reproduced well on tomato, but neither reproduced upon nor caused injury to strawberry or rough lemon. Morphologically, females of the Sanford population have a lower "c" value and a greater number of tail annules than those of the Gainesville and Fuller''s Crossing populations. Females and males of the Fuller''s Crossing population had higher "a" values than those of the other two populations.     

Relationship between cell number,cell size and fruit size of seeded fruits of tomato (Lycopersicon esculentum Mill.), and those induced parthenocarpically by the application of plant growth regulators

Application of GA₃, IAA or 4-CPA to tomato ovaries induced the development of parthenocarpic fruit, which showed different growth rates. In the pericarp cell division and cell enlargement was affected differentially. GA₃-induced fruits had considerably less but larger cells than seeded control fruits, IAA treatment resulted in the same number of cells but these were smaller and 4-CPA treatment induced fruits with about 20% more cells. Reduction in cell number had a similar effect on final fruit size as diminution of cell size. A reduction in the number of cell division centres (area around vascular bundles) as well as changes in the degree of endoploidy are possible reasons for the observed reductions in cell numbers. Hormonal causes for the different number and size of pericarp cells after the various treatments are discussed.     

The effect of assimilate supply on fruit growth and hormone levels in tomato plants

Rates of dry matter accumulation and contents of starch, sugars and abscisic acid (ABA) of tomato fruits differed significantly during development at three positions (proximal, middle and distal) on a truss. Proximal fruits, which accumulated dry matter most rapidly during early development, generally had least ABA (per g DW).Partial defoliation reduced carbon accumulation by all fruits but increased ABA, especially in distal fruit, and indoleacetic acid (IAA), particularly in proximal fruits. The ABA content of leaves in partially defoliated plants was similar to that of leaves on non-defoliated plants.Removal of distal fruits on a truss enhanced carbon movement to the remaining proximal fruits and also increased their ABA content early in development but did not affect their IAA content. On the other hand, when proximal fruit were removed there was no large or lasting increased accumulation of carbon by the remaining distal fruits and they contained less ABA and IAA than fruits on plants without fruit thinning. Leaf carbon and ABA levels showed no marked trend in response to fruit thinning.The amount of carbon in the stems was increased by fruit thinning but decreased by partial defoliation.The possible roles of ABA and IAA in regulating fruit growth are discussed.Part of this work has been presented to a Symposium on Phloem loading and related processes at Bad Grund/Oberhar, W. Germany, July 1979.