Effect of Ca on Al-induced activation of antioxidant enzymes in the needles of hinoki cypress (Chamaecyparis obtusa)

The effect of CA(NO₃)₂ on the active oxygen scavenging system in hinoki cypress (Chamaecyparis obtusa) seedlings cultured in a nutrient solution containing aluminum was examined. The hinoki cypress seedlings were transferred to nutrient solutions containing 5 mM AlCl₃ together with various concentrations of Ca(NO₃)₂ in pots containing glass beads and Teflon tips. The growth in height and dry matter allocation to each organ was little influenced over a period of 12 weeks by either Al or the concentration of Ca(NO₃)₂. The activity of superoxide dismutase (SOD) in the needles was stimulated by Al, and the effect of Al was lowered significantly by simultaneous application of 25 mM Ca(NO₃)₂. At week 1, the activity of catalase (CAT) in the needles was increased by Al, but the effect was no longer observed at week 12. The Al concentration in the roots was increased by treatment with Al, whereas the Al concentration in needles was not. These results indicate that rhizospheric Al stress stimulates antioxidative enzyme activities in hinoki cypress needles and the activation of the enzymes is suppressed by addition of Ca. The transmission of Al stress to the needles, which induced a change in the enzyme activity, is not caused by the transfer of the Al ion itself from roots to needles. This work was supported in part by funding from the Japan Science and Technology Corporation, the CREST program 1996–2001, and the Center for Forest Decline Studies.     

Individual variation in low boiling point monoterpenes emitted from hinoki (Chamaecyparis obtusa) needles

Variations in the compositions of low-boilingpoint (LBP) monoterpenes in needle samples of 50 hinoki (Chamaecyparis obtusa) trees were investigated using the headspace technique. Considerable compositional variations were revealed, especially in sabinene composition. The sabinene composition varied from 4.9% to 78.0% of the total LBP monoterpenes.-Pinene, myrcene, and limonene also showed considerable variations (9.0%–32.7%, 5.5%–22.6%, 3.6%–29.0% respectively). Analysis of the monoterpene composition allowed definition of four chemotypes based on the contingency table test. No correlation was observed between tree size and LBP monoterpene composition, indicating that the compositional variation in LBP monoterpene exists genetically in this population of hinoki.Part of this paper was presented at the 11th annual meeting of the Chugoku Shikoku branch of the Japan Wood Research Society, Matsue, September 1999     

Efficient plant regeneration of Hinoki cypress (Chamaecyparis obtusa) via somatic embryogenesis

This report describes the efficient plant regeneration of Chamaecyparis obtusa Sieb et Zucc. via somatic embryogenesis. Embryogenic cultures were initiated from megagametophytes containing immature zygotic embryos. Embryogenic cultures were maintained and proliferated by 2–3-week interval subcultures in medium supplemented with 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine. High maturation frequencies of cotyledonary embryos were obtained on maturation medium containing maltose, polyethylene glycol, activated charcoal, and abscisic acid. Somatic embryos germinated readily after transfer to plant growth regulator-free medium. Growth of regenerated emblings has been monitored in a greenhouse.     

Seasonal change in the temperature coefficientQ 10 for respiration of field-grown hinoki cypress (Chamaecyparis obtusa) trees

The effect of temperature upon nighttime respiration was examined on four different sized sample trees in a 17-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand over two years. Seasonal changes inQ ₁₀ values and their responses to mean temperature were investigated. On the basis of the monthly relationships between nighttime respiration (r) and temperature inside a chamber (θ),r=r ₀exp (kθ), theQ ₁₀ value (=exp(10k)) was calculated. TheQ ₁₀ values were high (Q ₁₀≥3.0) in winter when mean air temperature was low, and gradually decreased toward summer (Q ₁₀≤1.5) through spring with increasing temperature. TheQ ₁₀ values were negatively correlated with mean air temperature. The response ofQ ₁₀ values to mean air temperature was described by a single equation, regardless of tree size. This result, which might be characteristic of this species, shows that respiration ofC. obtusa trees is promoted by slight increases of air temperature in winter season. On the other hand, temperature sensitivity of total respiration reduced during growing season when ambient temperature was high. These chaning temperature sensitivity according to seasons may depend on the seasonal change of the ratio of growth respiration to total respiration. It is concluded that changes in temperature due to changing seasons not only change respiration rate, but also change the response of respiration rate to temperature by shiftingQ ₁₀ values.     

Progeny differences of hinoki (Chamaecyparis obtusa) and sawara (C. pisifera) against resinous stem canker disease and spatial distribution of damage (disease severity) in a progeny test

The incidence and severity of resinous stem canker disease were investigated in hinoki (Chamaecyparis obtusa) and sawara (C. pisifera) at a progeny test located in Yamatsuri Town, Fukushima Prefecture, Japan. Symptoms of the disease were observed in 307 trees out of 933 investigated trees (32.9%). The damage was more severe on lower slopes than on upper slopes, indicating that micro-environmental factors are causally associated with the occurrence of the disease. The severity of the disease varied both among nine open-pollinated progenies derived from hinoki plus-tree clones and among 13 progenies derived from pollination between hinoki plus-tree clones and the mixed-pollen of hinoki plus-tree clones. The severity of the disease also varied with height above the ground. This tendency was most obvious where the disease was most severe. An estimation of the narrow sense heritability,h ², of 0.214, was obtained from analysis of the 13 progenies derived from pollination with mixed-pollen. The heritability derived from material that had not been subjected to selection against the disease, indicated that breeding to enhance resistance would be possible to control the disease. The interaction between environments and progenies in relation to severity of the disease is also discussed. Ms. Setsuko Chiba and Mr. Mamoru Ueta gave us vigorous supports, and Mr. Haruki Orita, Dr. Tomiyasu Miyaura, and Dr. Shinichiro Ito gave us many helpful comments. We deeply appreciated their cooperation. The study was supported by a grant from the Ministry of Agriculture, Forestry. and Fisheries of Japan.     

Effects of elevated CO2 concentration on the respiratory behavior of the branches of field-grown hinoki cypress (Chamaecyparis obtusa)

The effects of elevated atmospheric CO₂ concentrations on the nighttime respiration were examined for two sample branches of a hinoki cypress tree (Chamaecyparis obtusa) growing in the field with an open gas exchange system for a one-year period from July 1994 to June 1995. The branches were of a similar size and located at a similar position within the crown. One branch was subjected to an elevated CO₂ concentration of 800 μmol mol⁻¹ and the other was subjected to ambient air which had a CO₂ concentration of about 370 μmol mol⁻¹. Nighttime respiration rate was higher in elevated CO₂ level than in ambient CO₂ level. The relationship between nighttime respiration and the corresponding nighttime air temperature was fitted by the exponential function in every month of the year. The segregation of regression lines between the two CO₂ treatments increased gradually as the seasons progressed during the treatment period. TheQ ₁₀ values for nighttime respiration were lower in elevated CO₂ (1.9 ≤Q ₁₀ ≤ 3.7) than in ambient CO₂ (2.4 ≤Q ₁₀ ≤ 4.5) in every month of the year. TheQ ₁₀ was inversely related to the monthly mean nighttime air temperature in both elevated and ambient CO₂. The estimated daily nighttime respiration rate under both CO₂ treatments had a similar seasonal pattern, which almost synchronized with the temperature change. The respiration ratio of elevated CO₂ to ambient CO₂ increased gradually from 1.1 to 1.6 until the end of the experiment. Our results indicate that the CO₂ level and the temperature have a strong interactive effect on respiration and suggest that a potential increase in respiration of branches will occur when ambient CO₂ increases.     

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.     

Genetic variation in fruitfulness in a hinoki (Chamaecyparis obtusa Endl.) seed orchard and its impact on the maintenance of genetic diversity in seedlots

Genetic variation in seed/cone production among clones was studied in a hinoki (Chamaecyparis obtusa Endl.) seed orchard containing 25 plus-trees by analyzing the number of cones, the yield of cones and seeds of individual ramets for 5 successive years (1982 to 1986). There was significant variation among clones each year and parental contribution in the seed orchard. Specifically, in the years 1982, 1983, 1984, 1985, and 1986, 20% of the clones produced 37.2, 60.6, 36.0, 44.3, and 44.8% of the total cones, respectively. The size of the crop greatly influenced the parental balance in the resulting seed/cone crops. The product moment correlation coefficients and Spearman’s coefficients of rank correlation were small and insignificant between consecutive years, but large and highly significant between alternate years, suggesting the presence of carry-over effects in seed/cone production. The broad-sense heritability on a clone mean basis was 0.74 ± 0.15 for the number of cones, 0.72 ± 0.14 for the yield of cones, and 0.68 ± 0.13 for the yield of seeds. The corresponding heritabilities from analyses combined over all years were 0.24, 0.558, and 0.724, respectively. These results indicate that seed/cone production in hinoki is under strong genetic control. Several managerial measures are discussed that maintain the genetic diversity in seedlots used for reforestation, by reducing the variation in seed/cone production among clones and producing seed crops with equal contributions from all parents.     

Changes in soil chemical and physical characteristics in Japanese cypress (Chamaecyparis obtusa Endl.) stands by mixture of deciduous broad-leaved trees in the northern Kanto region of Japan

In order to clarify the effects of a mixture of deciduous broad-leaved trees on soil fertility, we investigated litter biomass accumulation, mineral soil chemical and physical characteristics, characteristics of nitrogen mineralization, and the mutual relationships between them in Japanese cypress (Chamaecyparis obtusa) stands mixed with deciduous broad-leaved trees at different ratios (mixture ratio; MR = 0, 16, 33, 43, 100% by basal area) in the northern Kanto region of Japan. Litter biomass in the forest floor and mineral soil was 19.1 Mg ha⁻¹ in MR 0% and decreased approximately 60 % in MR 33%, MR 43% and MR100%. The permeability at 0–5 cm soil depth in MR100% was twice as much as that in MR 0%. Increases in soil permeability were likely due to larger soil pores in the higher MR with much accumulated deciduous broad-leaves. At 0–5 cm soil depth, the differences in carbon concentration among the plots were not clear. On the other hand, carbon concentrations at 5–10 cm depth increased from 90 g kg⁻¹ to 147 g kg⁻¹ with increases in MR from 0% to 100%. Concentrations of exchangeable bases increased two to four times with increases in MR from 0 to 100% at 0–10 cm depth. Soil pH (H₂O) generally increased with increases in MR at each depth. The rates of net nitrogen mineralization at 0–5 cm depthin vitro increased from 25 to 87 mg kg⁻¹ 2 weeks⁻¹ with increases in MR from 0 to 100%. However, increases in nitrification with increases in MR were not clear compared with nitrogen mineralization. These results indicated that a mixture of deciduous broad-leaved trees in a Japanese cypress stand was effective in preventing soil fertility decline. This study was supported by a grant from the Showa Shell Sekiyu Fundation for Promotion of Environmental Research. A part of this study was presented at the 7th International Congress of Ecology (1998).     

The composition of volatiles from tatami mats containing hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) wood-wool and its decline over the long term

Volatiles inside tatami mats containing hinoki (Chamaecyparis obtusa) wood-wool as padding were analyzed. Volatiles were collected with solid-phase microextraction (SPME) fibers in a small chamber prepared in tatami mats and assayed by gas chromatography. Most of the detected compounds are typically found in hinoki extractives. Monoterpenes rapidly decreased at the beginning of the experiment, while the dispersion of sesquiterpenes that contain hydroxyl groups was observed to last more than 1 year. These sesquiterpenes, T-cadinols, and α-cadinols may play a role in the suppression of house dust mites. Part of this report was presented at the 55th Annual Meeting of the Japan Wood Research Society in Kyoto, March 2005     

Nitrogen nutrient mechanism in secondary succession process of the mixed broad-leaved/Korean pine (Pinus koraiensis) forest

Chemical and biochemical analysis methods were used to monitor the variations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad -leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, ammonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those ofsecondary birch forests those are in succession stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such asPinus Koraiensis, Tilia amurensis, Acer mono and alsoFraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the ammonium rather than those of the pioneer trees species in secondary birch forest, such asPopulus davidiava andBetula platyphylla. Because they have more ammonium in their leaves and roots, especiallyPinus koraiensis. Populus davidvana andBetula platyphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others. In secondary birch forest, the regeneration trees species adapt their nitrogen nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.