Nastajanje lesa pri pravem kostanju (Castanea sativa Mill.) z rastišča v Italiji : diplomsko delo - univerzitetni študij

Vovk, Matej (author), Čufar, Katarina (mentor)

Z metodo odvzema mikro izvrtkov so med 16. marcem in 28. oktobrom 2009 s prsne višine (1,3 m) desetih dreves pravega kostanja (Castanea sativa Mill.) z rastišča Monti Cimini v pokrajini Lazio v Italiji tedensko odvzemali vzorce. Pripravili so mikroskopske preparate, ki so vsebovali les, kambij in floem in jih proučili s svetlobnim mikroskopom Nikon Eclipse 800 (svetlo polje in polarizirana svetloba), digitalno kamero DS-Fi1 in sistemom za analizo slike NIS Elements BR3. Za vsak teden so določili širino ksilemskega prirastka tekoče branike in ovrednotili razvojno stopnjo celic v lesu. Med 31. marcem in 7. aprilom 2009 so zasledili nastanek prvih trahej. Sinteza sekundarne celične stene in lignifikacija se je pri prvih trahejah začela v tednu med 23. in 29. aprilom. Biosinteza sekundarne celične stene in lignina se je najprej začela okoli prvih trahej, pozneje pa še v preostalem tkivu. Med 20. in 29. majem se je zaključilo nastajanje ranega lesa. Rani les je vseboval 2-3 vence trahej, njegov delež pa je bil večji v ožjih branikah. Najbolj intenzivno nastajanje celic ksilemske branike so zabeležili v času od začetka junija do začetka julija. Kasni les je začel nastajati med 20. in 29. majem, dokončno pa se je oblikoval med 24. septembrom in 1. oktobrom. Branika je nastajala približno 4 mesece, pri čemer so opazili razlike med drevesi. Končna širina branike 2009 je povprečju znašala 3648 m (3516 703 m). Rezultate o rasti branike so izravnali z Gompertzovo, Chapman-Richardovo, Weibullovo in Korfovo rastno funkcijo. Pri primerjavi teh rastnih funkcij so ugotovili, da se vse dobro prilegajo meritvam širin nastajajoče ksilemske branike. Gompertzova funkcija se zdi najprimernejša, ker se pri njej točka prevoja najbolje ujema z dejansko kulminacijo tekočega prirastka. Parametri te funkcije so tudi sicer primerni za opis dinamike nastajanja lesa.

• Language: Slovenian
• Keywords: pravi kostanj, Castanea sativa, Italija, ksilogeneza, nastanek lesa, kambijeva aktivnost, diferenciacija
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Vovk]
• Year: 2010
• Number of pages: X, 64 f.
• PID: 20.500.12556/RUL-15941
• UDC: 630*81(043.2)=163.6
• COBISS.SI-ID: 3082662
• Publication date in RUL: 11.07.2014

VOVK, Matej, 2010, Nastajanje lesa pri pravem kostanju (Castanea sativa Mill.) z rastišča v Italiji : diplomsko delo - univerzitetni študij [online]. Bachelor’s thesis. Ljubljana : M. Vovk. [Accessed 28 May 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=15941

Secondary language

• Language: Unknown

Abstract

Tissue samples from the breast height (1.3 m) of the selected chestnut trees (Castanea sativa Mill.) growing at a site of Monti Cimini in the Lazio region (Italy) were collected from 16 March until 28 October 2009. The samples were taken with the micro-coring method at weekly intervals. Microscopic cross-sections that contained xylem, cambium and phloem were prepared and analyzed with the light microscope Nikon Eclipse 800 (bright field and polarized light), digital camera DS-Fi1 and image analysis system NIS ElementsBR3. The width of the xylem increment of the current annual ring was measured on samples taken at weekly intervals. The phase of cell differentiation was recorded as well. Occurrence of the first vessels was detected between 31 March and 7 April 2009. The synthesis and lignification of their secondary cell walls started between 23 and 29 April 2009. They started around the first vessels and spread afterwards to the surrounding tissue. The most intensive rate of xylem formation was detected from the beginning of June until the beginning of July. Earlywood consisted of 2-3 rows of vessels; its proportion was larger in narrower tree rings. Latewood started to develop in the period between 20 and 29 May and was fully developed by the week from 24 September till 1 October. Tree ring formation lasted for approximately 4 months, considerable differences among the trees were observed. The final average tree ring width was 3648 m (3516 703 m). The results of xylem growth were fitted with Gompertz, Chapman-Richard, Weibull and Korf growth functions. All of them were useful for fitting the data, but the Gompertz function seemed to be the most appropriate. The culmination calculated with this function, optimally agreed with the actual culmination of the increment. The parameters of this function are also very useful for describing the formation of the tree ring.