Efficacy of New Inexpensive Cyanobacterial Biofertilizer Including its Shelf-life

Summary Four cyanobacterial inoculants all significantly increased grain and straw yield of rice either alone or in combination with chemical fertilizer. A saving of 25 kg N ha⁻¹ can be attained through cyanobacterial fertilization. Tobacco waste-based cyanobacterial biofertilizer was best in performance. Cyanobacterial acetylene reducing activity in vivo varied from 144 to 255 μmol C₂H₄ m⁻² h⁻¹ in different treatments, being highest for tobacco-based cyanobacterial biofertilizer integrated with 50% chemical N. The nutrient balance for total N, available N, total P and available P was found positive in biofertilizer- and chemical fertilizer-treated plots. The total and available K showed negative balance in all the treatments. The shelf-life of cyanobacterial biofertilizer can be augmented by selecting translucent packing material, dry mixing and paddy straw as a carrier. Dry mixing and a mixing ratio of 50:50 (carrier:cyanobacteria) gave better inoculum loading and shelf-life. Decrease in cyanobacterial population was least in dried cyanobacterial flacks, indicating a possibility of developing cyanobacterial biofertilizer without carrier mixing at the time of production.     

野生稻抗病虫基因的研究与利用

野生稻是宝贵的种质资源,具有丰富的遗传多样性。多项研究表明,野生稻对多种病虫害有较强的抗性。但由于野生稻的远缘杂交存在许多的弊端,因而采用常规杂交技术不能选育出新的抗性品种而未能这到利用野生稻抗性基因的目的。可考虑从野生稻中提取抗性活性成分用于植物源农药的开发研究,但在实际的研究中发现其有效活性成分含量较少和基因遗传连锁障碍等两个问题。基因的分子标记定住技术可解决这两个难点。使野生稻特别是非AA组野生稻的抗病虫基因在植物源农药开发中的利用成为现实。     

长穗颈不育水稻穗颈节间的细胞学研究

通过对长选3S和培矮64S定长的穗颈节间细胞个数统计和细胞长度的测量,得出长穗颈不育水稻穗颈节间伸长的细胞学变化规律.自然条件下长穗颈不育水稻长选3S穗颈节间比对照培矮64S长18.0cm,其纵列厚壁细胞和薄壁细胞数分别比培矮64S多1248个和580个;厚壁细胞和薄壁细胞平均长度分别比培矮64S长23.3μm和38.3μm,尤其是中部区段的厚壁细胞和薄壁细胞分别比对照长24.8μm和48.7μm;穗颈节间薄壁细胞的长度由基部区段至中部区段呈突跃式增加,而由中部至顶部区段则呈缓慢减少的趋势.隐性长穗颈温敏核不育水稻穗颈节间伸长是由细胞数目增多和细胞长度增加双重作用所致,其中后者作用更显著.     

离子注入后诱导水稻多倍化的效果

利用3份二倍体水稻为材料,以氮离子束为诱变源,研究了离子注入后所引起的生物学效应和离子注入对水稻多倍化的效果。研究结果表明,氮离子束对3份二倍体水稻材料的效应因材料种类和离子注入剂量不同而异。N 注入处理后对利用秋水仙素诱导水稻多倍化的效果比较明显,但效果的明显程度则因离子注入剂量不同或秋水仙素诱导时间不同或试验材料的遗传背景不同而表现出一定的差异。在秋水仙素对试验材料的诱导时间为24 h的各个处理中,N 离子注入剂量为6.76×1016N /cm2的处理似乎更好,而在秋水仙素对试验材料的诱导时间为48 h的各个处理中,N 离子注入剂量为0.52×1016N /cm2的处理则更有利于获得同源四倍体材料。经过2个~3个世代的筛选之后并通过染色体核型分析,在试验材料的后代中已经获得了一些同源四倍体水稻材料。     

航天与辐射共诱变在水稻育种中的应用

利用航天诱变与辐射诱变相结合的方法进行水稻新种质、新品种的选育,显著地提高其突变频率和突变类型,提高诱变育种的选择效果,育成1个两系杂交水稻新组合“培两优721”及一批优质水稻新种质和新品系(组合)。     

A Novel Integrated Method Tor Large-scale Detection,Identification, and Quantification of Widely Targeted Metabolites： Application in the Study of Rice Metabolomics

Liquid chromatography-mass spectrometry （LC-MS）-based metabolomics has been facilitated by the con- struction of MSz spectral tag （MS2T） library from the total scan ESI MS/MS data, and the development of widely targeted metabolomics method using MS/MS data gathered from authentic standards. In this report, a novel strategy called step- wise multiple ion monitoring-enhanced product ions （stepwise MIM-EPI） was developed to construct the MS2T library, in which stepwise MIM was used as survey scans to trigger the acquisition of EPI. A total number of 698 （almost） non- redundant metabolites with MS2 spectra were obtained, of which 135 metabolites were identified/annotated. Integrating the data gathered from our MS2T library and other available multiple reaction monitoring （MRM） information, a widely targeted metabolomics method was developed to quantify 277 metabolites, including some phytohormones. Evaluation of the dehydration responses and natural variations of these metabolites in rice leaf not only suggested the coordinated regulation of abscisic acid （ABA） with metabolites such as serotonin derivative（s）, polyamine conjugates under drought stress, but also revealed some C-glycosylated flavones as the potential markers for the discrimination of indica and japonica rice subspecies. The new MS2T library construction and widely targeted metabolomics strategy could be used as a tool for rice functional genomics.     

Effect of fungi–termite interaction on the chlorophyll content of three rice varieties grown on ultisol soil of Ikenne,south-west Nigeria

The effect of fungi–termite interaction on three rice varieties was conducted in a screen house at the Africa Rice Center (AfricaRice) Ibadan, Nigeria. Of the 10 fungi species (Fusarium verticilloides, Trichoderma sp., Aspergillus niger, Aspergillus flavus, Macrophoma sp., Neurospora sp., Botryodiplodia theobromae, Penicillum sp., Rhizopus sp. and Sclerotium rolfsii) isolated from termites, soil and rice plants, F. verticilloides, Trichoderma sp. and B. theobromae were used for the interaction study. Each fungus was inoculated singly and in combinations with termite into the root of each rice variety in potted soil. Leaf samples were taken to measure the chlorophyll content which is a major parameter to estimate effect of termite–fungi interaction. The chlorophyll content of the inoculated rice plants was significantly reduced when compared with the control. Fungi interaction with termite had significant reduction on the chlorophyll content. The synergistic relationship between the fungi and the termite was discussed.     

Tiller number is altered in the ascorbic acid-deficient rice suppressed for l-galactono-1,4-lactone dehydrogenase

The tiller of rice (Oryza sativa L.), which determines the panicle number per plant, is an important agronomic trait for grain production. Ascorbic acid (Asc) is a major plant antioxidant that serves many functions in plants. l-Galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3) is an enzyme that catalyzes the last step of Asc biosynthesis in plants. Here we show that the GLDH-suppressed transgenic rices, GI-1 and GI-2, which have constitutively low (between 30% and 50%) leaf Asc content compared with the wild-type plants, exhibit a significantly reduced tiller number. Moreover, lower growth rate and plant height were observed in the Asc-deficient plants relative to the trait values of the wild-type plants at different tillering stages. Further examination showed that the deficiency of Asc resulted in a higher lipid peroxidation, a loss of chlorophyll, a loss of carotenoids, and a lower rate of CO₂ assimilation. In addition, the level of abscisic acid was higher in GI-1 plants, while the level of jasmonic acid was higher in GI-1 and GI-2 plants at different tillering stages. The results we presented here indicated that Asc deficiency was likely responsible for the promotion of premature senescence, which was accompanied by a marked decrease in photosynthesis. These observations support the conclusion that the deficiency of Asc alters the tiller number in the GLDH-suppressed transgenics through promoting premature senescence and changing phytohormones related to senescence.     

Auxin distribution is differentially affected by nitrate in roots of two rice cultivars differing in responsiveness to nitrogen

Background and Aims

Although ammonium (NH₄⁺) is the preferred form of nitrogen over nitrate (NO₃⁻) for rice (Oryza sativa), lateral root (LR) growth in roots is enhanced by partial NO₃⁻ nutrition (PNN). The roles of auxin distribution and polar transport in LR formation in response to localized NO₃⁻ availability are not known.

Methods

Time-course studies in a split-root experimental system were used to investigate LR development patterns, auxin distribution, polar auxin transport and expression of auxin transporter genes in LR zones in response to localized PNN in ‘Nanguang’ and ‘Elio’ rice cultivars, which show high and low responsiveness to NO₃⁻, respectively. Patterns of auxin distribution and the effects of polar auxin transport inhibitors were also examined in DR5::GUS transgenic plants.

Key Results

Initiation of LRs was enhanced by PNN after 7 d cultivation in ‘Nanguang’ but not in ‘Elio’. Auxin concentration in the roots of ‘Nanguang’ increased by approx. 24 % after 5 d cultivation with PNN compared with NH₄⁺ as the sole nitrogen source, but no difference was observed in ‘Elio’. More auxin flux into the LR zone in ‘Nanguang’ roots was observed in response to NO₃⁻ compared with NH₄⁺ treatment. A greater number of auxin influx and efflux transporter genes showed increased expression in the LR zone in response to PNN in ‘Nanguang’ than in ‘Elio’.

Conclusions

The results indicate that higher NO₃⁻ responsiveness is associated with greater auxin accumulation in the LR zone and is strongly related to a higher rate of LR initiation in the cultivar ‘Nanguang’.