[Study on optimal harvesting period and rational medicinal parts of Zanthoxylum nitidum based on statistics of main effective components].

To determine the optimal harvesting period and rational medicinal parts of Zanthoxylum nitidum, the main effective components of cultivated Z. nitidum samples, which originate from various growth years, harvesting months, and different parts were analyzed and compared with the wild samples. HPLC was performed on a Kinetex C18 column(4. 6 mm×100 mm, 2. 6 µm) with the gradient elution of 0. 3% phosphoric acid solution-acetonitrile(80 ∶ 20) containing 0. 2% triethylamine. The flow rate was 1. 0 m L·min-1, and the detection wavelength was 273 nm. The column temperature was 30 ℃. Nitidine chloride and chelerythrine, the main effective components, were determined as the markers. The results showed there was no significant difference in the contents of the main effective components among the roots of wild and cultivated Z. nitidum, as well as the roots and roots + stems of cultivated Z. nitidum. The statistical results of HCA and PCA indicated that the roots and stems could be clearly distinguished, but no distinction could be made between wild and cultivated products, which was consistent with the results of the significance analysis. The total contents of nitidine chloride and chelerythrine in roots and stems of Z. nitidum of 1-6 years old were 0. 114%-0. 256% and 0. 030%-0. 133%, respectively. These results suggested a positive correlation between the content of the main effective components and the growth years. No significant difference was observed between the contents of samples harvested in different seasons, indicating that the harvest season had no effect on the content of the main effective components of the Z. nitidum samples. The total contents of nitidine chloride and chelerythrine of the dried Z. nitidum samples(excluding branches) from three plantation bases were 0. 308%±0. 123% in Yunfu, 0. 192%±0. 025% in Maoming, and 0. 197%±0. 052% in Nanning, respectively, and they were all not less than 0. 15%, or in other words, the roots(including fibrous roots, taproots, and underground stems) and stems(aboveground stems) of Z. nitidum transplanted for more than 2. 5 years can meet the medical requirements. This study demonstrates that the cultivated Z. nitidum could be used as a valid substitute for the wild Z. nitidum, which provides a guarantee for the sustainable development and the application of Z. nitidum resources. The stems and roots could be considered medicinal parts of Z. nitidum. It is recommended to revise the medicinal parts of Z. nitidum to dried roots and stems in the next edition of Chinese Pharmacopoeia, and the medicinal parts can be harvested all year round. In order to ensure the content of effective components and clinical effectiveness, the root and stem should be harvested for medical use after the seedlings of Z. nitidum have been transplanted for more than three years.

Fire effects on the population structure of Zanthoxylum rhoifolium Lam (Rutaceae) in a Brazilian savanna / Efeitos do fogo na estrutura da população de Zanthoxylum rhoifolium Lam (Rutaceae) em uma savana brasileira

Since cerrado fires may impede the growth of seedlings into trees, they may shape the population of woody species. In this study, we assessed the effects of a severe fire on the population structure and spatial distribution of Zanthoxylum rhoifolium, a widespread cerrado tree. We were interested to know the importance of the resprouting and sexual reproduction in regenerating the population. The study area had been for about six years protected from fire, before a severe fire at the end of the dry season in 2006. We sampled and measured all individuals of Z. rhoifolium found in 80 plots of 25 m². We found 149 individuals before the fire and 112 after the fire, of which 77 were resprouts from burned seedlings and saplings. We did not find significant differences between the population structure before and after the fire. The spatial distribution of the population remained clumped after the fire. Thus, the Z. rhoifolium population was very resilient to a severe fire. We did not find any new seedlings. As a consequence, resprouting seems to be more important than sexual reproduction in promptly regenerating the Z. rhoifolium populations.

Uma vez que as queimadas no cerrado podem impedir o crescimento de plântulas, elas podem moldar a população de espécies arbóreas. Neste estudo, avaliamos os efeitos de uma queimada severa na estrutura e na distribuição espacial da população de Zanthoxylum rhoifolium, uma espécie de árvore comum no cerrado. O objetivo era saber a importância relativa do rebrotamento e da reprodução sexuada na regeneração da população. A área de estudo, há aproximadamente seis anos sem queimar, sofreu uma queimada severa no final da estação seca de 2006. Amostramos todos os indivíduos de Z. rhoifolium encontrados em 80 parcelas de 25 m². Encontramos 149 indivíduos antes do fogo e 112 depois dele, dos quais 77 eram rebrotas de plântulas e jovens queimados. Não encontramos diferenças significativas entre a estrutura da população antes e após o fogo. A distribuição espacial da população permaneceu agregada após a queimada. Portanto, a população de Z. rhoifolium foi resiliente ao fogo. Não foi encontrada nenhuma nova plântula. Consequentemente, o rebrotamento parece ser mais importante que a reprodução sexuada na regeneração imediata das populações de Z. rhoifolium.