Assessing raindrop impact energy at the forest floor in a mature Japanese cypress plantation using continuous raindrop-sizing instruments

The raindrop size distribution of throughfall and open rainfall was monitored continuously during a rainfall event using laser raindrop-sizing instruments (LD gauges), in order to calculate the raindrop impact energy in a plantation of mature Japanese cypress (Chamaecyparis obtusa), where surface erosion at the forest floor had been a problem. Data from two rainfall events were analyzed. The LD gauges recorded qualitative raindrop size distribution, and the capture rate during each rainfall event was used to manipulate raindrop data quantitatively. Throughfall and open rainfall comparisons revealed several important differences. First, throughfall raindrops were fewer in number and larger in size than open rainfall drops. In one rainfall event, for example, throughfall raindrops were less than one-fifth as frequent as open rainfall raindrops; in addition, the maximum throughfall raindrop diameter was 6.35mm compared to 3.31mm for open rainfall raindrops. Second, throughfall raindrops that were larger than the largest open rainfall raindrops comprised 63.8% of the throughfall precipitation by volume. Third, total raindrop impact energy from throughfall was over twice that of open rainfall. Moreover, comparison of throughfall events implied that throughfall raindrops did not always have a uniform distribution between different events or among different periods of time in one rainfall event, in contrast to findings in previous studies which showed that throughfall raindrops had a uniform size distribution independent of rainfall intensity. It is possible that an abrupt transition of throughfall intensity from low to high changes the distribution of throughfall raindrops.     

Effect of carpropamid on secondary infection by rice blast fungus

Carpropamid (WIN™, KTU 3616) provides good control of leaf and panicle blast by ‘one-shot’ nursery-box treatment. It inhibits melanin biosynthesis in appressorial cells of Pyricularia oryzae, making them hyaline. Penetration by infection hyphae from the hyaline appressoria into rice epidermal cells is substantially hindered. In addition, the spread of rice blast spores from primary lesions to the other parts of the plant leading to secondary infection is largely prevented when the plants are treated with carpropamid by spray or water surface application. Secondary infection was simulated in a glass chamber fitted with an ultrasonic humidifier. On treated plants, many blast spores formed in the lesions, but the number of air spora that were dispersed from the lesions decreased significantly. A similar suppression of the spore liberation was observed in vitro when lesions on rice leaf segments, or discs from Pyricularia cultures on oatmeal agar were treated with the chemical. Spores from treated lesions or from the cultures on oatmeal agar amended with the chemical germinated normally and produced well-melanized appressoria on cellophane membranes. In addition, the spores proved to be fully pathogenic towards rice seedlings, producing normal disease symptoms. These results strongly suggest that carpropamid reduces the secondary infection of rice by Pyricularia by specifically hindering spore liberation. © 1999 Society of Chemical Industry     

Effect of height-to-diameter ratio on stem stiffness of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The lumber from sugi plantations in Japan displays large intra- and intertree variation in mechanical properties, even within a stand. These variations seem to be induced by the effects of the characteristics of cultivars as well as the effects of growth traits on mechanical properties. Therefore, the effects of growth traits on mechanical properties per cultivar need to be precisely examined. In this study, we focused on the effects of growth traits, especially height-to-diameter ratio (H/D ratio), on stem stiffness per cultivar. Sixteen cultivars were classified into three groups according to the relationships between stem stiffness and growth traits. In cultivars that showed a close correlation between growth traits and stem stiffness, it was assumed that stem stiffness could be controlled to a certain extent by silvicultural practices using the H/D ratio as an indicator. In cultivars that showed a weak correlation between growth traits and stem stiffness, selecting cultivars for the production of logs with higher mechanical properties seemed to be effective; in this study, Kumotoshi, Tanoaka, and Edanaga were found to be suitable. Tree age and site index may be important factors for producing wood with higher mechanical properties.     

Classification of the genus Bacillus based on MALDI-TOF MS analysis of ribosomal proteins coded in S10 and spc operons

A rapid bacterial identification method by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) using ribosomal proteins coded in S10 and spc operons as biomarkers, named the S10-GERMS (the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum) method, was applied for the genus Bacillus a Gram-positive bacterium. The S10-GERMS method could successfully distinguish the difference between B. subtilis subsp. subtilis NBRC 13719(T) and B. subtilis subsp. spizizenii NBRC 101239(T) because of the mass difference of 2 ribosomal subunit proteins, despite the difference of only 2 bases in the 16S rRNA gene between them. The 8 selected reliable and reproducible ribosomal subunit proteins without disturbance of S/N level on MALDI-TOF MS analysis, S10, S14, S19, L18, L22, L24, L29, and L30, coded in S10 and spc operons were significantly useful biomarkers for rapid bacterial classification at species and strain levels by the S10-GERMS method of genus Bacillus strains without purification of ribosomal proteins.     

Reliability in somatic cell count measurement of clinical mastitis milk using DeLaval cell counter

Somatic cell counts (SCC) measurements are typically performed using quantitative methods, such as the Breed method (Breed) and the Fossomatic method (FSCC). The DeLaval cell counter (DCC) developed recently is a quantitative somatic cell counter with a low initial cost and superior portability. However, since the DCC was specifically developed for measuring SCC of ≤ 4 × 10⁶ cells/mL milk from bulk tanks or individual cows, its reliability for estimating SCC that exceed this concentration has not yet been clarified. This study therefore examined whether it is possible to accurately measure SCC by diluting milk samples with initial SCC of 4 × 10⁶ cells/mL, as seen in clinical mastitis milk. We collected milk samples from 99 quarters of 99 Holstein cows with clinical mastitis. These milk samples were diluted 10‐fold with saline and thoroughly mixed before performing SCC measurement with the DCC. The correlation coefficients of SCC measured by the FSCC, Breed and DCC methods indicated strong correlations between each pair of methods. The findings showed that DCC can be used to identify bovine clinical mastitis milk and is useful as a quantitative SCC measurement device on farm sites.     

Distribution of recesses in the olfactory organ of African lungfish Protopterus aethiopicus

In the olfactory organ of lungfish, recesses at the bases of lamellae comprise sensory and nonsensory epithelia. The sensory epithelium of the recesses, the recess epithelium, is distinguished from the olfactory epithelium covering the lamella by the absence of ciliated olfactory receptor cells. Therefore, it has been suggested that the recess epithelium is a primordium of the vomeronasal organ of tetrapods. However, developmental changes in the number and distribution of recesses in the olfactory organ of lungfish were unknown. We examined four Protopterus aethiopicus specimens of body lengths 215–800 mm to determine the localization of recesses in their olfactory organs. Histological examination showed recesses at the bases of lamellae in all individuals examined. The recesses were localized mainly in the medial and caudal parts of the olfactory organs, especially in juveniles. Compared to smaller fish, larger fish had a larger number of recesses, distributed more broadly in their olfactory organs. Significance of the recess localization and its relationship to the function of lungfish olfactory organ warrants further investigation.     

Biocontrol of Phytophthora Root Rot of Angelica Trees by Enterobacter cloacae and Serratia ficaria Strains

Bacterial strains isolated from the rhizosphere of angelica trees were evaluated for their antagonistic activity against Phytophthora cactorum, a causal agent of Phytophthora root rot. Of these, three bacterial strains, designated as T-1-8, T-1-14 and T-1-23, strongly inhibited mycelial growth of P. cactorum ARE-862 in a dual-culture plate assay. Biocontrol activity of these strains was then examined by dipping root of young seedlings of angelica trees into a bacterial suspension. The incidence of Phytophthora root rot was markedly suppressed for at least 79 days in pot tests when treated seedlings were planted in naturally infested soil. The suppression was maintained through June of the next year. In addition, these strains significantly reduced the development of Phytophthora root rot up to 47 days in naturally infested field and up to 63 days (the last day of testing) in an artificially (moderately) infested field. Based on their main bacteriological properties, strain T-1-14 was identified as Enterobacter cloacae and T-1-8 and T-1-23 were identified as Serratia ficaria. Received 5 July 1999/ Accepted in revised form 25 October 1999     

A new pyrethroid-type ester with strong knockdown activity

Thirteen pyrethroid-type esters of substituted 1(or 3)-hydroxymethylimidazolidine-2, 4-dione were synthesised and their knockdown activities against houseflies, mosquitoes and cockroaches were examined. Knockdown activities of 2,4-dioxo-1-prop-2-ynylimidazolidin-3-ylmethyl esters in oil solutions were higher than those of known knockdown pyrethroids; three of the compounds also possessed strong knockdown and flushing-out activities against cockroaches.     

Cold tolerance at the early growth stage in wild and cultivated rice

The present study was conducted to understand the pattern of variation and the genetic bases for cold tolerance at the early growth stage in Asian rice. The genetic variation was investigated at the germination, plumule and seedling stages among 57 strains including cultivated rice (Oryza sativa ssp. indica and ssp. japonica) and its wild progenitor (Oryza rufipogon). The significant differentiation of cold tolerance was observed among the taxonomically divided groups. At the germination stage, both indica and japonica subspecies tended to be more tolerant than O. rufipogon, whereas at the plumule and seedling stages, ssp. japonica tended to be more tolerant than ssp. indica and O. rufipogon. Furthermore, in cold tolerance at the plumule stage, the clinal variation across the latitude of origins was observed within O. rufipogon and ssp. japonica, suggesting that the current pattern of variation seems to have been shaped by both their phylogenetic histories and on-going adaptation to the local environments. QTL analysis between O. sativa ssp. japonica (tolerant) and O. rufipogon (susceptible) revealed five putative QTLs for cold tolerance at the plumule and seedling stages but not at the germination stage. Substitution mapping was also carried out to precisely locate the two major QTLs for cold tolerance at the plumule stage, which could be used for improvement of tolerance to cold stress in ssp. indica.