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The length of the seminal root (SR) axis and the number andlength of lateral roots (LRs) of sorghum (Sorghum bicolor Moench)were markedly inhibited by taro [Colocasia esculenta (L.) Schott]residues incorporated into a sand growing medium. The sand profilewas divided equally into zones with and without residues. Productionand elongation of the first-order LRs of the SR axis facingthe zone containing taro residues were severely suppressed.On the side facing the zone that was free of residues, productionand elongation of LRs was not inhibited. SR and LR growth wasdrastically impaired and many plants were killed when taro residueswere incorporated in large amounts into the uppermost 2 cm ofthe growing medium. The activity of the allelopathic substancesin the root zone appeared to be location-specific. Sorghum bicolor, seminal root, lateral root, Colocasia esculenta, taro, taro residues, allelopathic substances, root growth 相似文献
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Tomoko GANAHA Machiko NOHARA Shinsuke SATO Nami UECHI Kenzou YAMAGISHI Satoshi YAMAUCHI Junichi YUKAWA 《Entomological Science》2007,10(2):157-169
In the past, Rhopalomyia longitubifex, Rhopalomyia shinjii, and Rhopalomyia sp. (Diptera: Cecidomyiidae) have been regarded as independent species based on differences in the sizes and shapes of axillary bud galls induced on Artemisia montana (Asteraceae) in Japan and A. princeps in Japan and Korea. However, comparison of morphological features and molecular sequencing data indicate that these Rhopalomyia gall midges are identical and that the differences in gall shape are polymorphisms, although the measurements of gall height and diameter overlap slightly. This finding suggests that although galls have frequently been regarded as extensions of the phenotype of a species, differences in gall shape may not always be reliable for identifying gall‐inducing cecidomyiids. The older name, R. longitubifex, is applied to these gall midges, and the names that were applied to this species on later occasions are revised or synonymized. The mature and immature stages of R. longitubifex are redescribed and information on the distribution, host range, and gall size of this species is provided. We also discuss the role of gall polymorphism in the early stages of speciation. 相似文献
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A. PRIYATMOJO R. YAMAUCHI D. E. CARLING K. KAGEYAMA & M. HYAKUMACHI 《Journal of Phytopathology》2002,150(1):1-5
Cellular fatty acid analysis was employed to differentiate three varieties of Rhizoctonia circinata ; var. circinata , var. oryzae and var. zeae . Eight fatty acids including myristic (14 : 0), pentadecanoic (15 : 0), palmitic (16 : 0), palmitoleic (16 : 1 cis 9), stearic (18 : 0), oleic (18 : 1 cis 9), linoleic (18 : 2 cis 9,12) and linolenic (18 : 3 cis 9,12) acids were present in isolates of all three varieties of R. circinata . Heptadecanoic acid (17 : 0) was detected in isolates of R. circinata var. zeae but not in isolates of R. circinata var. circinata or R. circinata var. oryzae . Palmitic, oleic and linoleic acids were the major fatty acids found, comprising 94–98% of the whole-cell fatty acid content. The remaining fatty acids were present in small amounts. Based on the composition (%) of fatty acids, isolates of R. circinata var. circinata , R. circinata var. oryzae and R. circinata var. zeae were clearly differentiated into three groups as shown by principal component and cluster analyses. This finding agrees well with the grouping of R. circinata into three varieties based on differences in colony morphology of the vegetative state. In principal component and cluster analysis, isolates of R. circinata var. circinata from Japan and Alaska were indistinguishable. 相似文献
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Net photosynthetic rate, leaf area, tillering, shoot weight,and leaf area ratio for 35 F1 rice (Oryza sativa L.) hybridsduring the vegetative stage were compared with correspondingvalues for parental varieties. Shoot weight and leaf area showedheterosis. However, hybrid vigour was not reflected in net photosyntheticrate. Leaf area was closely correlated with heteroses in shootdry weight and tillering. Thus F1 rice hybrids grow vigorouslybecause of their high leaf area development, which is causedby high tillering. Key words: F1 rice hybrid, Net photosynthetic rate, Leaf area 相似文献
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Fractal Analysis of Plant Root Systems 总被引:13,自引:1,他引:12
The morphology of root systems of crop plants was analysed byfractal geometry using an image processing system. Results indicatethat these root systems have a fractal structure (D; 1.48 相似文献
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