The Algorithm of Pole-Assignment Self Tuning Robust Control

An control algorithm with goed robustness has been developed,based on the combination of poletassignment self- tuning control algorithm with robust estimation and control al-gorithms,while the input signal and process parameters are varied on a large scale. The design of controller based on presented algorithm is simple,with good robustness for parameter changes and a strong ability for overcoming determined disturbance.The simulating research results proved the ef-fectiveness of the pole- assienment self-tuning robust control algorithm.     

Coffee resistance to Colletotrichum kahawae is associated with lignification, accumulation of phenols and cell death at infection sites

Histological and ultrastructural studies were undertaken to compare Colletotrichum kahawae growth and the sequence of responses it induced in resistant and susceptible coffee genotypes. Coffee resistance was characterized by a restricted fungal growth associated with hypersensitive-like cell death and early accumulation of phenolic compounds, such as flavonoids (cytoplasmic contents) and hydroxycinnamic acid derivatives (cell walls). This accumulation of phenols in the cell walls preceded their lignification and thickening. In the susceptible genotype, a late accumulation of hydroxycinnamic acid derivatives in a number of cell walls and the encasement of some intracellular hyphae were also observed, but these delayed host responses did not prevent fungal growth and sporulation.     

河口县小粒种咖啡生产的农业气候条件区划与分析

在实地勘察、走访调查、资料收集与整理的基础上,依据生态环境相似性及生物资源开发近似性原则,采用气候相似性的原理建立回归方程,对河口县小粒种咖啡生产的农业气候条件进行(区划)分析,提出河口县小粒种咖啡产业发展的建议。     

施用咖啡果皮对咖啡幼苗生长及土壤理化性状的影响

通过盆栽试验研究施用不同量的咖啡果皮对咖啡幼苗生长及土壤理化性状的影响。结果表明:施用5%(果皮与土壤质量比)以上咖啡果皮的咖啡幼苗地上部、根系干重,总根长,根系直径及根系总体积显著低于对照处理;随咖啡果皮施用量的增加,咖啡幼苗长势显著变差;施用5%以上的咖啡果皮可显著增加土壤碱解氮、速效磷、速效钾养分含量和土壤脲酶、酸性磷酸酶活性,但土壤p H显著下降。综上所述,施用5%以上直接堆沤腐熟的咖啡果皮会抑制咖啡幼苗生长,降低土壤p H,但可显著提高土壤养分含量和土壤脲酶、酸性磷酸酶活性,增加土壤养分有效性。     

咖啡叶片DNA提取方法的比较研究

以咖啡成熟叶片为材料,进行多种DNA提取方法比较研究,并通过琼脂糖凝胶电泳和紫外分光光度计检测所提的DNA样品。结果表明,CTAB改良Ⅰ和CTAB改良Ⅱ均可用于咖啡叶片的DNA提取,尤其是CTAB改良Ⅱ法,提取的DNA产量较CTAB改良Ⅰ高,能满足后续分子生物学研究的要求。     

普洱市小粒咖啡病虫害种类调查分析

对云南省普洱市小粒咖啡主要栽种区病虫害及荫蔽树种类、杂草和荫蔽树与咖啡病虫害的关系进行调查研究。结果发现普洱市小粒咖啡害虫有13种,病害有7种,常用荫蔽树有17种。文中还分析杂草和荫蔽树与咖啡病虫害关系,就普洱市咖农的管理技术提出建议。     

Coffee bacterial diseases: a plethora of scientific opportunities

Coffee is a very important crop for several tropical countries across different continents. The diseases bacterial halo blight (BHB), bacterial leaf spot (BLS), bacterial leaf blight (BLB) and coffee leaf scorch (CLS), caused by the bacterial pathogens Pseudomonas syringae pv. garcae (Psgc), P. syringae pv. tabaci (Psta), Pseudomonas cichorii (Pch) and Xylella fastidiosa subsp. pauca (Xfp), respectively, cause significant reductions in coffee production, although other minor bacterial diseases have also been reported in some countries. Little research progress has been made on aspects that are relevant for control and management of these diseases. In all cases, there is an urgent need to develop rapid and more reliable methods for early detection of the pathogens in order to minimize their negative impact on coffee production. Because of the high rate of intra- and intersubspecific recombination occurring in X. fastidiosa, a permanent revision of the detection methods is necessary. Greater efforts should be made to understand the genetic and virulence diversity of Psgc, Psta and Pch populations. Early studies reported the identification of potential sources of resistance against Psgc and Psta, but, to date, no resistance gene has been isolated. Little effort has been made to understand the biology and molecular mechanisms underlying the interaction between Coffea spp. and these pathogenic bacteria. This review discusses the recent progress on the molecular mechanisms used by these bacteria to cause diseases on other plant species, in order to provide a guideline for the establishment of future research programmes.     

咖啡-荔枝混农林系统中小粒咖啡营养诊断及平衡施肥效应研究

定位试验研究咖啡-荔枝混农林系统中N、P、K不同用量及配比咖啡营养状况结果表明,缺N对小粒咖啡产量影响最大,其次为K,而P的影响较小;喷施微量元素B、Zn可明显增加咖啡产量。N、P、K肥配比为1∶0.5∶1,咖啡产量随N、P、K用量的增加而提高,鲜果产量为15~30t/hm2。建议思茅地区小粒咖啡营养诊断指标为N25~30g/kg,P1.0~1.5g/kg,K15~25g/kg,Ca10~12g/kg,Mg2.5~5.0g/kg,Zn10~15mg/kg和B40~50mg/kg;N、P2O5和K2O平衡施肥年最佳用量为N50~100g/株、P2O525~50g/株和K2O50~100g/株。     

不同遮光和施氮水平对小粒咖啡生长和光合特性的影响

【目的】探明小粒咖啡Coffea arabica幼树最佳的光照和施氮耦合模式。【方法】试验设置3个遮光水平:不遮光(S0,自然光照)、轻度遮光(S1,65%自然光照)、重度遮光(S2,30%自然光照), 3个施氮水平:无氮(N0,0 g·kg-1)、中氮(N1,0.20 g·kg-1)、高氮(N2,0.40 g·kg-1),研究不同遮光和施氮水平对小粒咖啡生长、日均光合特性和生物量累积的影响。【结果】随遮光度的增加叶绿素总量呈上升趋势。与S0处理相比,S1处理小粒咖啡叶片净光合速率、气孔导度、表观光能利用效率和总生物量分别提高13.54%、18.54%、127.77%和12.41%;S2处理总生物量减少11.55%。与N0处理相比,N1处理叶片净光合速率、气孔导度、表观光能利用效率和总生物量分别增加27.25%、20.77%、10.80%和18.47%,N2处理的上述性状分别增加14.85%、25.99%、41.65%和21.02%。与S0N0相比,随遮光度和施氮量的增加叶片蒸腾速率和表观光能利用效率增大,叶片水分利用效率呈先增后减趋势。【结论】小粒咖啡最优的遮光和施氮耦合模式为轻度遮光下高氮组合(S1N2),该组合有利于获得较高的叶片水光利用效率和生物量。     

Genetic diversity and structure of Hemileia vastatrix populations on Coffea spp.

Coffee leaf rust is the most limiting disease for coffee cultivation in Brazil. Despite its importance, relatively little is known about the genetic diversity of Hemileia vastatrix, the rust causal agent. In this work, the DNA from 112 monopustule isolates from different geographic locations and coffee genotypes were analysed by amplified fragment length polymorphisms (AFLP). The objectives were to assess the influence of the host and geographic origin on the diversity and population differentiation in H. vastatrix. The fungal population showed a low level of genotypic diversity. Gene diversity (h) was 0·027 and the hypothesis of random mating in the total population was rejected, but evidence for recombination was found for two subpopulations (São Paulo and Paraná). The analysis of molecular variance revealed that 90% of the genetic distribution of the pathogen occurs among isolates within the subpopulation (states or host of origin). There was no correlation between geographic and genetic distance (r = ?0·024, P = 0·74), which together with the high number of migrants and the low degree of differentiation in populations of H. vastatrix, is consistent with the fact that the inoculum is probably easily dispersed by wind over long distances, allowing dispersal of the pathogen among coffee growing areas in Brazil. Therefore, it is difficult to predict the durability of resistant sources to coffee rust. The recommendation for the breeding programmes is thus to incorporate multigenic resistance as a control strategy.