The penetration rate of laser pulses transmitted from a small-footprint airborne LiDAR: a case study in closed canopy, middle-aged pure sugi (Cryptomeria japonica D. Don) and hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.) stands in Japan

Penetration rates of laser pulses transmitted from a small-footprint airborne light detection and ranging (LiDAR) system in closed-canopy, middle-aged (40–50 years old) hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.) and sugi (Cryptomeria japonica D. Don) plantations that had similar levels of canopy openness were studied. The number of transmitted pulses was 107 427 points/ha for the hinoki cypress stand and 122 883 points/ha for the sugi stand. The penetration rates of the first (P_f) and second pulses (P_s) that reached the ground were 0.1% and 1.0% in the hinoki cypress stand, and 2.6% and 5.5% in the sugi stand, respectively. Penetration rates for the total number of pulses (P_f+s) that reached the ground within each stand were 1.1% and 8.1%, respectively, and values for P_f+s, P_f, and P_s for sugi and hinoki cypress stands were significantly different (P < 0.001). The results of this study indicated that the generation of accurate digital terrain models in dense hinoki cypress stands with complex topographies using only the data from laser pulses with poor laser penetration rates is likely to be difficult.     

The Effect of Colchicine as a Chromosome Doubling Agent for Wheat-Rye Hybrids as Influenced by pH, Method of Application, and Post-Treatment Environment

Hybrids of wheat (Triticum durum) × rye (Secale montanum) (2n = 21) were treated with a 0.06 % solution of colchicine. In the induction of fertile plants, fertile spikes, and seed-set per spike, the root immersion technique was 21.7 %, 14.1 %, and 4.4 % respectively more effective than the use of the inverted vial. Colchicine solutions ranging in pH from 3.5 to 7.5 with the root immersion technique reached the highest frequencies of fertile (or partially fertile) hybrids (77.7 %), and fertile spikes (68.9 %) at a pH 5.5 used for the treatment, although the highest overall percentage of large Q seeds resulted from treatments at low pH (3.5). The overall mean frequency of induced fertile plants was six-fold higher when treated in a growth chamber (19/15 °C day/night temperature and 18 h photoperiod) compared to treatments conducted in a greenhouse. The frequency of euploidy (2n = 42) was found to be highest in the large seed class and lowest, i.e. just about 50 %, in the class of small seeds.     

Applicability of the quantification of genetically modified organisms to foods processed from maize and soy

The applicability of quantifying genetically modified (GM) maize and soy to processed foods was investigated using heat treatment processing models. The detection methods were based on real-time quantitative polymerase chain reaction (PCR) analysis. Ground seeds of insect resistant GM maize (MON810) and glyphosate tolerant Roundup Ready (RR) soy were dissolved in water and were heat treated by autoclaving for various time intervals. The calculated copy numbers of the recombinant and taxon specific deoxyribonucleic acid (DNA) sequences in the extracted DNA solution were found to decrease with time. This decrease was influenced by the PCR-amplified size. The conversion factor (Cf), which is the ratio of the recombinant DNA sequence to the taxon specific DNA sequence and is used as a constant number for calculating GM% at each event, tended to be stable when the sizes of PCR products of two DNA sequences were nearly equal. The results suggested that the size of the PCR product plays a key role in the quantification of GM organisms in processed foods. It is believed that the Cf of the endosperm (3n) is influenced by whether the GM originated from a paternal or maternal source. The embryos and endosperms were separated from the F1 generation seeds of five GM maize events, and their Cf values were measured. Both paternal and maternal GM events were identified. In these, the endosperm Cf was lower than that of the embryo, and the embryo Cf was lower than that of the endosperm. These results demonstrate the difficulties encountered in the determination of GM% in maize grains (F2 generation) and in processed foods from maize and soy.     

Effects of fertilization, crop year, variety, and provenance factors on mineral concentrations in onions

Mineral concentrations of onions (Allium cepa L.) grown under various conditions, including factors (fertilization, crop year, variety, and provenance), were investigated to clarify how much each factor contributes to the variation of their concentrations. This was because the mineral concentrations might be affected by various factors. The ultimate goal of this study was to develop a technique to determine the geographic origins of onions by mineral composition. Samples were onions grown under various conditions at 52 fields in 18 farms in Hokkaido, Japan. Twenty-six elements (Li, Na, Mg, Al, P, K, Ca, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Mo, Cd, Cs, Ba, La, Ce, Nd, Gd, W, and Tl) in these samples were determined by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. Fertilization conditions and crop years of onions caused variations of P, Ni, Cu, Rb, Sr, Mo, Cs, and Tl concentrations in onions; different onion varieties also showed variations in numerous element concentrations. However, the variations of mineral compositions of onions by these factors were smaller than the differences between production places with a few exceptions. Furthermore, Na, Rb, and Cs in group IA of the periodic table, Ca, Sr, and Ba in group IIA, and Zn and Cd in group IIB showed similar concentration patterns by group; this result demonstrated that elements in the same periodic groups behaved similarly in terms of their absorption in onions.     

Role of sulphide reduction by magnesium hydroxide on the sediment of the eutrophic closed bay

This study was focused on the effect of magnesium hydroxide (Mg(OH)₂) for improving the sediment of aquaculture field and eutrophic closed estuaries. Sediment samples were collected from Omura Bay, Nagasaki, Japan. The change in pH, acid volatile sulphides (AVS) and dissolved organic carbon (DOC) in interstitial water of the sediment samples were measured before and after 20‐day incubation under the condition of overlapping seawater at 25°C with 0.3–0.4 mg/L of dissolved oxygen (DO). Hydrogen sulphide (H₂S) and the dsrA gene copy number of Grp3 sulphate‐reducing bacteria (SRB) in the sediment samples were also measured at 7‐day incubation under the same condition. The pH of Mg(OH)₂ treatment group was significantly increased from 7.43 to 8.25; it was higher compared to the control group which pH was maintained around 7.6. Meanwhile, the AVS content of Mg(OH)₂ treatment group was significantly reduced and the value was lower than the control group after the 20‐day incubation. Each concentration of interstitial water DOC in the treatment group and the control group increased after the incubation from initial value of 15.4–40.1 and 29.0  mg/L respectively. Furthermore, simultaneous decrease in H₂S and the dsrA gene copy number of Grp3 SRB was observed at the end of the 7‐day incubation by adding Mg(OH)₂. It is concluded that the loss of activity of SRB was strongly related to the decrease in sulphide (H₂S and AVS) and the increase in DOC was due to the alkalization of the sediment by adding Mg(OH)₂.     

Possible vector insect of mulberry dwarf phytoplasma, Tautoneura mori Matsumura

Mulberry dwarf (MD) phytoplasma was surveyed for its presence in presumably nonvector insects (two species of leafhoppers, thrips, and spider mites) collected from MD-diseased trees. MD phytoplasma was found in all species by nested polymerase chain reaction using specific primers for the 16Sr I-group phytoplasma. By electron microscopy, MD phytoplasma was observed in the salivary glands of the leafhopper Tautoneura mori Matsumura. In addition, the vector ability of T. mori was verified through bioassay; 25% of seedlings inoculated with infective leafhoppers had MD symptoms, suggesting that T. mori may act as a vector of MD phytoplasma in fields in some cases.     

Root Rot of Miniature Roses Caused by Pythium helicoides

Miniature roses growing in an ebb-and-flow watering system developed dieback during the summer growing season of 1996 in Gifu Prefecture. The main diagnostic symptoms were chlorosis of leaf followed by blight, and a brown, water-soaked root rot followed by dieback. Pythium isolates were recovered from the rotted root. The isolates form proliferous ellipsoidal papillate sporangia, spherical smooth oogonia, elongate antheridia, and aplerotic oospores. The optimum temperature for hyphal growth was 35°C with a growth rate of 34 mm/24 hr. Optimum temperature of zoospore formation (25-30°C) was lower than that of mycelial growth, and zoospores were produced even at 10°C. The isolates were identified as P. helicoides on the basis of these characteristics. In pathogenicity tests disease severity was highest at the highest tested temperature (35°C) at which the disease naturally occurred in summer. Four days after inoculation, the leaves turned yellow and the roots had a water-soaked rot, followed by leaf blight and root dieback after 7 days. The disease transmission test showed that diseased plants were found throughout the bench after 10 days. Received 4 July 2001/ Accepted in revised form 10 October 2001     

Partial Purification of Thai Isolate of Citrus Huanglongbing (Greening) Bacterium and Antiserum Production for Serological Diagnosis

We aimed to improve the purification of citrus Huanglongbing (greening) bacterium (HB), Candidatus Liberobacter asiaticum and to produce an antiserum against HB. Periwinkle plants Catharantus roseum L. graft-inoculated with HB were used to produce an antiserum. All young leaves of new shoots incubated at 20–25°C and 25–30°C, a few mature leaves incubated at 20–25°C, and all mature leaves incubated first at 25–30°C and later transferred to 20–25°C developed yellowing symptoms and were then used to prepare immunogen. The HB was partially purified from these leaves by an improved method that included a macerating enzyme treatment of the midribs of infected leaves and homogenization of infected phloem sieve tissues. An antiserum raised against partially purified HB reacted clearly at a dilution of 1/16 with HB-infected citrus extract prepared at a concentration of 40 times, but did not react with healthy or tristeza virus-infected citrus extract in microprecipitin tests. Received 23 August 2002/ Accepted in revised form 4 December 2002     

Different prostaglandin F2α secretion in response to oxytocin injection between pregnant and non‐pregnant cows: effect of the day of oxytocin challenge test for determining the difference

The present study was conducted to determine the difference in plasma prostaglandin F₂α metabolite concentrations following oxytocin (OT) challenge between pregnant and non‐pregnant cows. Experiment 1: cows were subjected to the OT challenge test on days 12, 14 or 16 (day of estrus = day 0) with or without prior insemination and plasma 13,14‐dihydro‐15‐keto prostaglandin F₂α (PGFM) concentrations were measured from ?30 to 180 min after OT injection. On day 16, the increment of plasma PGFM concentrations in response to OT injection was significantly smaller in pregnant than that in cyclic cows. On days 12 and 14, there was little OT‐induced PGFM secretion and no difference in PGFM increase between the pregnant and cyclic cows. Experiment 2: cows were inseminated on day 0 and subjected to the OT challenge test on day 16. Cows were classified into non‐pregnant/early embryonic death (NP/EED), late embryonic death (LED) and pregnant (PREG) groups. The increment of PGFM concentrations in response to OT injection was less in both PREG and LED groups than that in the NP/EED group. In conclusion, plasma PGFM secretion induced by OT is suggested as the base of pregnancy diagnosis prior to returning estrus in cows.     

Maternal exposure of low dose of TCDD modulates the expression of estrogen receptor subunits of male gonads in offspring

We have analyzed the effects of low-dose transplacental and lactational exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gene expression relating to the dioxin and sexual hormone cascade, and demonstrated the effects on testicular growth and sexual maturation in male offspring rats. TCDD (10 ng/kg) was administered to dams on Days 7 and 14 of gestation, and on Days 0, 7 and 14 after delivery. Gene expression of cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) in the liver of 17-day-old rats was significantly increased compared with controls. Furthermore, expression of estrogen receptors (ER)alpha and ERbeta was significantly increased at 17 and 42 days old, respectively in the testis of TCDD-administered rats compared with controls. Although testicular weight and the seminiferous tubule diameter were increased in 17-day-old rats, there was no difference in the number of germ cells between TCDD-treated and control animals. The expressions of androgen receptor and inhibin subunit genes were not significantly changed. These findings suggest that low-dose exposure of TCDD leads to unusual development of the testis by perturbation of steroid hormone homeostasis.