Study for Estimation of Needle Area of Sugi Stand : The Relationship between Needle Area per Shoot Length and Light Conditions within the Canopy

8年生のシヤカインスギ林分から採取された当年生シュートについて，シュート長いあたりの針葉数，針葉重量および針葉面積を樹冠内光環境との関係から調べた．その結果，シュート量長あたりの針薬数は相対照度に対してほぼ一定の値を示した．これに対しシュート長あたりの針薬重量および針葉面積は，相対照度の変化に対して負の相関を示した．これらの負の相関は個々の針葉のサイズが相対照度の低下に対して次第に大きくなることに起因していた．これらの解析の結果から，シュート艮あたりの針葉面積を用いて，枝，個体または林分の針葉面積を推定する場合，シュート形成時の光環境を考慮する必要があると考えられた．さらにシュート長あたりの針葉面積を一定であると仮定して，葉面積を推定した場合，過大評価をする可能性が指摘された．Needle number, weight and area per shoot length of current sugi (Cryptomeria japonica D. don) shoots were studied in assosiation with the light conditions within the canopy. Needle number per shoot length had little correlation (r = -0.134) with relative light intensity (RLI). On the other hand, needle weight and area per shoot length had strong negative correlation with RLI. These negative correlations were due to a decrease in mean needle weight and area as RLI increased, a phenomenon in many broad-leaf species. Thus, the estimation of needle area of sugi tree and the stand is posible by measuring shoot length and by considering the change in needle area per shoot length with the change in light conditions

Dry Matter Allocation to Root System in Young Sugi (Cryptomeria japonica D. Don) Tree : Growth Analysis with Allometry

スギ幼齢木の地下部への乾物分配を明らかにするために，木部断面積血-現存量関係を相対成長関係を用いて解析した．地際木部断面積と地上部及び地下部の現存量との関係はそれぞれ異なる相対成長式で表された．これらの式の相対成長定数は異なったが相対成長係数はともに1に近い値を示し，地上部と地下部の成長率が等しいことが示された．個体内の1次枝や1次分枝根についても木部断面積-現存量関係に相対成長係数が1である相対成長関係が成立した，しかし1次分枝根をさらに細分した分枝根ではその関係は大きくばらついた．この理由として木部断面積に依存しない細根の発生や枯死による動態が影響していることが考えられた．個体間および1次枝および1次分枝根の木部断面積-現存量関係を比較すると，地上部，地下部ともそれぞれ同一式とみなされ，パイプモデルが成立していた．このことから地下部の現存量はパイプモデルを用いて推定することが可能であったが，地下部への正確な乾物分配量を把握するためにはパイプモデルでは表現できない細根の動態をモデル化する必要性が指摘された．Allometric relation between xylem cross-section area and biomass of each compartment was studied to reveal dry matter allocation to root system in five years old Sugi (Cryptomeria japonica) trees. Different allometric relations were obtained in top and root system among four trees. The constant coefficients of allometric equotion were different, but relative growth coefficients were nearly same, and approximated to \u221\u22. That fact indicated that relative growth rates in shoot and root system were same. Allometric relations between xylem basal area and biomass of primary shoot and primary branch root were obtained within a tree. However, secondary or more divided branch root biomass were not fitted to this allometric relation. Because, this relationship was affected by fine root production and mortality which were independed on xylem cross-sectional area. Two allometric relations obtained among trees and within a tree were similar in top and root system, respectively, and it was concluded a \u22pipe model\u22 existed not only in top system but also in root system. Root biomass could be estimated using the allometric relation, but that relation had no attention to fine root dynamics, so it could not use for correct dry matter allocation to root system

Neural Crest-derived Cells in the Oral and Maxillofacial Regions of Adult Mice: Isolation and Application for Regenerative Medicine

Neural crest cells emerge from the dorsal region of the fusing neural tube in vertebrate embryos, then migrate throughout tissues to differentiate into various cell types, including osteoblasts. In adults, subsets of neural crest-derived cells (NCDCs) reside as stem cells and are considered to be useful cell sources for regenerative medicine. Previous studies have suggested that these NCDC subsets persist into adulthood in mammals, especially those cells within the craniofacial compartments. Recently, our group found that NCDCs were scattered throughout tissues of the palate, gingiva, tongue, hair follicle, submandibular glands, and buccal mucosa of adult mice. NCDCs from the buccal mucosa can also form neurosphere-like structures that have the capability to differentiate into osteoblasts in the presence of bone morphogenetic protein-2. In addition, NCDCs in adults have characteristic gene expression profiles, especially their cell surface molecules. Thus, cell sorting using several specific cell surface molecules has been proposed as a useful method for isolating NCDCs with high purity. Together, these results suggest that NCDCs reside in various adult oral and maxillofacial regions, and possess the potential to differentiate into osteoblastic cells, indicating that these cells in adults may be a useful source for bone regeneration strategies. In this review, we discuss the distribution, isolation and osteoblastic differentiation potential of NCDCs isolated from various adult tissue sources in the oral and maxillofacial regions

Branching Characteristics of Primary Branch and Primary Roots of Sugi (Cryptomeria japonica D. Don) Cultivars

樹冠形態の異なるスギ2品種（アヤスギ，シャカイン）および実生苗の一次枝，一次根の形態を比較した．20cmの長さに切断された一次枝，一次根（枝ユニット，根ユニット）の先端断面積（T），基部断面積（B），分岐断面積（S）を測定し，相互の関係を解析した．枝ユニットにおいてはT+S=Bの単純パイプモデルが成立したが，品種間差は認められなかった．一方，根ユニットではT+S≦Bとなり細根の枯死が生じていることが推測され，樹形のパイプモデルが適用された，このパイプモデルから導かれた細根の枯死率を比較すると実生で大きく，挿し木品種で小さかった．一次枝と二次枝の成長量の比を示すユニットの|T/S比は，一次枝の成長とともに増大することがわかった．頂芽優性の強さを来すと考えられるT/S比の増加率を比較すると，シャカイン＞実生笛＞アヤスギの順に大きかった．また根ユニットではT/S比と一次根の成長との関連性は認められず，したがって頂芽優性は認められなかった．Branching characteristics of primary branches and primary roots were studied in three types of sugi (Cryptomeria japonica D. Don) differed in their growth patterns and crown form; two cultivars (cv. Ayasugi and cv. Shakain) and a seedling. Primary branches and roots were cut into pieces of 20cm in length, Each piece was classified as a branch unit or root unit. Top cross-sectional areas (T), bottom cross-sectional areas(B), and divergence cross-sectional areas (S) of the units were measured. The simple pipe model relation (T+S=B) was applied to branch units. The pipe model of tree form (T+S≦B)was applied to root units. The results indicated that fine root death occurs more frequently than branch death. Rates of fine root death calculated from 1-(T+S)/B, were high in seedling, and small in cv. Ayasugi and cv. Shakain. Relationships between T/S ratio and B of branch and root units were analyzed in order to compare the strength of apical domillance among the sample trees. T/S ratio of branch units increased proportionally to growth of the primary branch. Differences of the increase rates among sample trees indicated that the decreasing order of strength of apical dominance is as fol1ows:Shakain> seedling>Ayasugi. Apical dolninance was not significant in the root system, as the T/S ratio was not related to the growth of the primary root