Anatomical study of resin duct development in the bark of the lacquer tree (Toxicodendron vernicifluum (Stokes) F. A. Barkley) in relation to tree growth

{"title":"Anatomical study of resin duct development in the bark of the lacquer tree (Toxicodendron vernicifluum (Stokes) F. A. Barkley) in relation to tree growth","authors":"Katsushi Kuroda,&nbsp;Kenichi Yamane,&nbsp;Masanobu Tabata","doi":"10.1007/s00468-024-02582-x","DOIUrl":null,"url":null,"abstract":"<div><h3>Key message</h3><p>The formation of resin ducts of <i>Toxicodendron vernicifluum</i> bark is controlled by adjusting the number and size of resin ducts with increasing age.</p><h3>Abstract</h3><p><i>Toxicodendron vernicifluum</i> is a valuable tree species for harvesting lacquer fluid (urushi). Although resin ducts are crucial for increasing urushi production, the development of resin ducts with tree age in <i>T. vernicifluum</i> remains unclear. This study analyzed the characteristics of normal resin ducts in the bark using stereomicroscopy and cryo-scanning electron microscopy. The current year’s trunk already possessed numerous resin ducts beneath the sclereid cell groups. These structures were approximately connected to the outer periphery of the inner bark, suggesting that they may serve an essential defensive function in young trunks with thin outer bark. Observations of the distribution pattern of resin ducts revealed that the total area per unit length, calculated by multiplying the number of resin ducts and each area, tended to increase with tree growth in all parts of the inner bark. However, the number, and the total area per unit length in the current year-formed inner bark (assumed 200 µm from the cambium) were high in the 1–3-year-old trunks, decreased significantly in one to 4–6-year-old trunks, and then remained approximately constant as the trunks aged, although the area of each resin duct showed a slight increase. The findings suggest that <i>T. vernicifluum</i> bark forms a large number of resin ducts to increase the total area of resin ducts during early stage of bark development. Once the bark has developed, the formation of resin ducts is controlled by adjusting the number and size of resin ducts. Furthermore, the size of resin ducts in the outer part of the inner bark became larger than the newly formed one, likely preventing tangential rupturing as the tangential bark size increased toward the outer. These results suggest that the physical and compositional protective functions provided by resin ducts are modified and regulated as the tree grows, offering insight into the highly sophisticated survival strategies of tree species.</p></div>","PeriodicalId":805,"journal":{"name":"Trees","volume":"39 1","pages":""},"PeriodicalIF":2.1000,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Trees","FirstCategoryId":"2","ListUrlMain":"https://link.springer.com/article/10.1007/s00468-024-02582-x","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"FORESTRY","Score":null,"Total":0}