Effects of rotation length and oxamyl on potato yield and the potato cyst-nematode, Globodera rostochiensis, in a sandy loam soil

In sandy loam infested with golden potato cyst-nematode, Globodera rostochiensis, oxamyl at 5.6 kg a.i. ha^-1 incorporated in the top 15 cm of the soil just before planting potatoes greatly reduced nematode population increase on susceptible cv. Désirée grown six, seven or eight years after the last susceptible potato crop, but did not significantly increase tuber yields. In four-course and two-course rotations, oxamyl also controlled increase of G. rostochiensis and greatly increased yields of both cv. Désirée and resistant cv. Maris Piper. Oxamyl maintained tuber yields in a four-course rotation at the same level as in a six to eight-course rotation. Decline of G. rostochiensis in the soil was much faster under barley in some two-course rotations than under barley in four-course rotations.     

137Cs uptake in spring wheat (Triticum aestivum L.cv. Tonic) at varying K supply

Spring wheat (Triticum aestivum L. cv. Tonic) was grown for 16 days in a sandy loam soil which was contaminated with ¹³⁷Cs. The soil was fertilised with K at three rates (0,1 and 2 mmol K per 950 g dry soil) and with NO₃ ^--N at two rates (0 and 2 mmol per 950 g dry soil) in a factorial design. The ¹³⁷Cs Activity Concentration (AC) in the shoot tissue significantly reduced 8.2-fold (nil N treatment, p<0.001) and 9.3-fold (highest N dose, p<0.001) with increasing K supply. In contrast, the K application increased the ¹³⁷Cs AC in soil solution 1.7 fold (nil N treatment) or had no significant effect (highest N dose). At similar K application, the application of N increased the ¹³⁷Cs AC in the shoot compared to the control. This effect is most probably due to the increased NH₄ ⁺ concentration in soil solution which increased the ¹³⁷Cs AC in soil solution. The soil solution composition (¹³⁷Cs and K concentration) in the rhizosphere was estimated from the average soil solution composition at day 16 and solute transport calculations. The ¹³⁷Cs AC in the shoot tissue was predicted from the estimated soil solution composition in the rhizosphere and the relationship between K concentration and ¹³⁷Cs uptake derived from a nutrient solution experiment. The predictions of ¹³⁷Cs AC's in the shoot are qualitatively correct for the fertiliser effects but underestimate the observations between 1.4 and 9.9 fold.     

Salinity and drought tolerance of mannitol-accumulating transgenic tobacco

Tobacco plants (Nicotiana tabacum L.) were transformed with a mannitol-1-phosphate dehydrogenase gene resulting in mannitol accumulation. Experiments were conducted to determine whether mannitol provides salt and/or drought stress protection through osmotic adjustment. Non-stressed transgenic plants were 20–25% smaller than non-stressed, non-transformed (wild-type) plants in both salinity and drought experiments. However, salt stress reduced dry weight in wild-type plants by 44%, but did not reduce the dry weight of transgenic plants. Transgenic plants adjusted osmotically by 0.57 MPa, whereas wild-type plants did not adjust osmotically in response to salt stress. Calculations of solute contribution to osmotic adjustment showed that mannitol contributed only 0-003-0-004 MPa to the 0.2 MPa difference in full turgor osmotic potential (π_o) between salt-stressed transgenic and wild-type plants. Assuming a cytoplasmic location for mannitol and that the cytoplasm constituted 5% of the total water volume, mannitol accounted for only 30–40% of the change in π_o of the cytoplasm. Inositol, a naturally occurring polyol in tobacco, accumulated in response to salt stress in both transgenic and wild-type plants, and was 3-fold more abundant than mannitol in transgenic plants. Drought stress reduced the leaf relative water content, leaf expansion, and dry weight of transgenic and wild-type plants. However, π_o was not significantly reduced by drought stress in transgenic or wild-type plants, despite an increase in non-structural carbohydrates and mannitol in droughted plants. We conclude that (1) mannitol was a relatively minor osmolyte in transgenic tobacco, but may have indirectly enhanced osmotic adjustment and salt tolerance; (2) inositol cannot substitute for mannitol in this role; (3) slower growth of the transgenic plants, and not the presence of mannitol per se, may have been the cause of greater salt tolerance, and (4) mannitol accumulation was enhanced by drought stress but did not affect π_o or drought tolerance.     

Plant regeneration from protoplasts ofCapsicum annuum L. cv. California Wonder

Plant regeneration from mesophyll protoplasts of pepper,Capsicum annuum L. cv. California Wonder has been demonstrated via shoot organogenesis. Protoplasts isolated from fully expanded leaves of 3-week-old axenic shoots when cultured in TM medium supplemented with 1 mg l ⁻¹ NAA, 1 mg l ⁻¹ 2,4-D, 0 5 mg l ⁻¹ BAP (CM 1) resulted in divisions with a frequency ranging from 20–25 %. Antioxidant ascorbic acid and polyvinylpyrrolidone (PVP) in the medium and incubation in the dark helped overcome browning of protoplasts. Microcalli and macrocalli were formed in TM medium containing 2 mg l ⁻¹ NAA and 0.5 mg l ⁻¹ BAP (CM II) and MS gelled medium containing 2 mg 1 ⁻¹ NAA and 0 5 mg 1 ⁻¹ BAP (CM III), respectively. Regeneration of plantlets was possible via caulogenesis. Microshoots, 2–5 percallus appeared on MS gelled medium enriched with 0.5 mg l ⁻¹ IAA, 2mg l ⁻¹ GA and l0mg l ⁻¹ BAP (CM IVc). Rooting of microshoots was obtained on half strength gelled medium containing 1 mg l ⁻¹ NAA and 0.5mg l ⁻¹ BAP. Protoplasts isolated from cotyledons failed to divide and degenerated eventually.     

Effect of nicotianamine on iron re-mobilization in de-rooted tomato seedlings

Summary An exogenous supply of nicotianamine is essential for the redistribution of⁵⁹iron via the symplast and the phloem to newly developing organs in de-rooted seedlings of the nicotianamine-less tomato mutantchloronerva. This observation supports the idea that nicotianamine could function as a translocator of iron within the symplast and the phloem.Abbreviations EDDHA ethylenediamine-N,N-bis(o-hydroxy-phenylacetic acid) - NA nicotianamine=(2S, 3S,3S)-N-[N-(3-amino-3-carboxypropyl)-3-amino-3-carboxypropyl]-azetidine-2-carboxylic acid This paper is part 36 in the seriesThe normalizing factor for the tomato mutant chloronerva. For part 35 see Stephan and Grün (1989)     

Voltage transients elicited by sudden step-up of auxin

Abstract It is hypothesized (i) that the molecular mechanism for the reception of friction and flexure and the mechanism by which auxin enhances ethylene production have in common a release of free calcium into the cytosol, (ii) that elevated cytosolic calcium initiates vesicle exocytosis, and (iii) that the vesicles release a factor or set of factors which depolarizes the plasmalemma and promotes ethylene synthesis. One consequence of such exocytosis should be small, extracellularly observable voltage transients. Transients, ranging in size up to 600 μV and possessing risetimes (10–90%) of approximately 200 ms, are known to be elicited in etiolated stems of Pisum sativum L. by friction and are here shown to be elicited by sudden increase of auxin concentration and also by a Ca²⁺ ionophore.     

Cloning,characterization and localization of <Emphasis Type="Italic">CHS</Emphasis> gene from blood orange, <Emphasis Type="Italic">Citrus sinensis</Emphasis> (L.) Osbeck cv. Ruby

Chalcone synthase (CHS) is involved in the biosynthesis of anthocyanin. In this study, a full-length DNA of CHS gene (named as CsCHS-bo) was cloned from the blood orange, Citrus sinensis (L.) Osbeck cv. Ruby. The gene was 1,512 bp in size containing an open reading frame (1,176 bp) encoding 391 amino acids. Comparative and bioinformatic analyses revealed that the deduced protein of CsCHS-bo was highly homologous to CHS from other plant species. The protein of CsCHS-bo had four CHS-specific conserved motifs and a CHS-family signature sequence GFGPG. Phylogenetic analysis indicated that the protein of CsCHS-bo was in a subgroup with CHS of Ruta Palmatum. The CsCHS-bo was localized to the chromosomes 2p, 4p and 6p by an improved fluorescence in situ hybridization technique, indicating that at least three copies of CsCHS-bo were present in the genome. The novel nucleotide sequence data published here have been deposited in the EMBL/DDBJ/GenBank databases under accession number EU410483.     

灵武长枣果实发育结构特征研究

采用石蜡切片法,研究不同发育时期灵武长枣果实的结构特征。结果表明:(1)缓慢生长期细胞增长缓慢,外果皮细胞5~6层,表皮细胞由1层薄壁细胞构成,呈长矩形或长椭圆形,表皮细胞以内的薄壁细胞不断增生,形成内表皮细胞。果实体积增大伴随着空腔的出现,中果皮维管束数量多;(2)第一次快速生长期细胞增长迅速,表皮细胞排列疏松,中果皮中的空腔增大速度最快,维管束主要分布在靠近外果皮和内果皮的中果皮部位;(3)减缓生长期表皮细胞变成圆形或椭圆形等不规则形状,细胞排列松散,内表皮细胞形状、大小不一,细胞排列疏松。中果皮中的空腔继续增大,维管束数目逐渐减少,但变化幅度较小;(4)第二次快速生长期外果皮细胞层数减少到3~4层,表皮细胞和内表皮细胞难以区分,空腔随着果实体积的增大达到最大,许多细胞单列排成网状结构,形成更大的腔,果皮中的维管束分布最少。在灵武长枣果实发育过程中,不同发育时期的不同部位其果实的形态解剖特征不同。     

A Preliminary Study on Direct Regeneration of Flower Buds from Peduncle Calli in Dracaena fragrans cv. massangeana

Flower buds were directly regenerated from calli in vitro in the woody plant Dracaena fragrans cv. massangeana Hort. On modified MS medium supplemented with 1.0 mg/L 6-BA and 1.0 mg/L IBA, two kinds of calli, A and B, were formed from the peduncle explants cultured for 5 months. Calli A were loose and on their surface there were many irregular granule-like structures (GLC); Calli B were compact and had bigger tumor-like structures (TLC) on their surface. When the GLC and TLC were transferred onto the medium respectively with 0.4 mg/L 6-BA and 1.0 mg/L IBA, flower buds were differentiated directly from the GLC but only vegetative buds and roots were differentiated from the TLC after culturing for 4 weeks. The GLC could be partly transformed into TLC in the continuous passage culture. Assays on hormones revealed that at a fixed IBA concentration of 0.4 mg/L the defferentiation frequency of flower budding was increased as the 6-BA concentration was decreased from 2.0 mg/L to 10 mg/L. Alternatively, at a fixed 6-BA concentration of 2.0 mg/L, the flower budding frequency was increased when the IBA concentration was changed from 0.4 mg/L to 1.0 mg/L. Moreover, the addition of 2.0 mg/L zeatin to the culture medium containing 2.0 mg/L 6-BA and 0.4 mg/L IBA was favorable to the regeneration of the flower buds. Nevertheless supplementing 1.0 mg/L GA3 into the medium on which the calli had differentiated into flower buds, the flower buds would gradually wither after 2 weeks in culture.     

在培养基中加入抗生素防止万年青茎段培养污染的研究

以玛丽安万年青茎段为试验材料,将浓度为50mg·L1的青霉素、氯霉素、利福平、庆大霉素、先锋霉素6号、链霉素和卡拉霉素7种抗生素分别经过过滤灭菌后加入到MS基本培养基,从中筛选出防止污染效果较好的两种抗生素,分别按50、100、150mg·L1的浓度加入到MS培养基中培养,以筛选出最适合浓度;然后再筛选出利福平和氯霉素的最佳浓度组合。结果表明:7种抗生素中以利福平和氯霉素防止污染效果较好,未污染率分别为68.42%和58.33%,成活率分别为65.79%和52.78%,利福平和氯霉素的浓度均为150mg·L1时防止污染的效果最佳;25mg·L1利福平+50mg·L1氯霉素和50mg·L1利福平+50mg·L1氯霉素组合,未污染率分别达到78.46%、85.18%,极显著高于50mg·L1利福平单独处理的效果。