Studies On Structures Of Vegetative Organs And Dynamic Changes Of Camptothecin In Camptotheca Acuminata

Camptotheca acuminata Decne., which belongs to Nyssaceae, is a perennial deciduous tree. It is a tree unique to China, mainly distributed in the areas of southwest and Yangtze River. The plant is known to botany and medicine because of CPT, which is an effective medicine in cancer treatment. The structures of vegetative organs were studied using anatomy methods. Callus from vegetative organs were induced and subcultured, different callus were also screened out, and their contents of CPT were identified by HPLC. Besides, the effects on CPT by putting revulsant on culture medium were analyzed. The dynamic changes of CPT contents were studied from different organs, different geographical sources, different season, different growth days and so on, and some basic rules of CPT accumulation were summarized. After one-year-old and two-year-old plants were dealt with UV-B radiation, Chlorophyll, MDA, SOD, Fpro in leaf and CPT content were determined. It is suggested that UV-B radiation can obviously enhance CPT content in Camptotheca acuminata. In this paper, the plant was studied systematically by the above methods, and some important results were listed below:1. The structure of longitudinal section of root of Camptotheca acuminata is the same to other dicotyledons, namely, it is composed of root cap, meristematic zone, elongation zone and maturation zone. The primary structures of root and stem are composed of epidermis, cortex and vascular cylinder. Osmiophilic cells are showed in cortexs and piths. In secondary growth, the cork cambium of root derives from pericycle, while the cork cambium of stem derives from cortex. With the secondary growth, the center of stem becomes hollow. With scanning electron microscope and optics microscope observing, stomatal apparatus are absent in adaxial epidermis of leafand abnormity in abaxial epidermis. The guard cells are nephroid, and subsidiary cells haven't been observed. The leaf surface has three types of trichomes, one type is unicellular non-glandular which is distributed in the adaxial and abaxial epidermis of leaf. Other types are glandular hairs, in which one is global distributed in both adaxial and abaxial epidermis, the other is olivary distributed only in the abaxial epidermis. In addition, we found that the younger the leaf is, the more the trichomes are distributed. The cross section of blade is composed of epidermis, mesophyll and vein, and osmiophilic cells are also found in the mesophyll.2. Callus from different organs were induced and subcultured. We screened out red, yellow and brown callus and determined their CPT contents by HPLC, the results show that CPT content in Callus from leaf is higher than the others, the contents in Callus from bud and stem are resemble, the CPT contents of red and yellow callus from any organs are higher than that of the brown callus. However, in the whole, the CPT contents in Callus are far lower than that in the plant, only a few percents. Revulsants put in culture medium have effects on CPT content in the callus. CPT content in callus dealt with the concentration of 0.1mg/L,lmg/L salicylic acid and methyl jasmonate increase, O.lmg/L salicylic acid obviously accelerates the accumation of CPT, the effect of jasmonate is little;While CPT contents in callus dealt with the concentration of 3mg/L, 5mg/L salicylic acid and methyl jasmonate decrease, and there have no CPT being detected in callus dealt with the concentration of 5mg/Ljasmonateare.3. In different organs, CPT content in young leaf, seed and young shoot is higher than that in xylem, it is lowest in piths. The content in caulody is higher than that in subbranches in the same plant. In different geographical provenances, CPT content of young shoot from Sichuan province is highest. In addition, CPT content of two-year-old plants is higher than that of one-year-old. In a year, CPT content of young shoot and young leaf presents seasonal rules, from April to July, CPT content gradually increase and reach a maximum in July, then gradually decrease. Besides, CPT content of two-year-old plants is higher than that of three-year-old. In time and space, CPT content of leaf gradually decreases with the leaf becoming mature. The content has differences between different parts in the same leaf.4. There are influences on chlorophyll, MDA, Fpro and activity of SOD by UV-B radiation. With the UV-B radiation time increasing, the content of chlorophyll gradually decreases, the content of Fpro gradually increases, the content of MDA increases in the whole, but the extent is small, the activity of SOD firstly decreases, then increases, lastly decreases. CPT contents in different organs increase in contrast with the reference, the contents increase more obvious in young leaf and young stem than that in root.