Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2020, Vol. 41 ›› Issue (11): 2245-2252.DOI: 10.3969/j.issn.1000-2561.2020.11.014

• Plant Cultivation, Physiology & Biochemistry • Previous Articles     Next Articles

Ecophysiological Responses of Azadirachta indica Seedlings to Different Water and Light Conditions

SUN Heng1,2,ZHANG Yanping1,WANG Youqiong1,WU Jiangchong1,PENG Xingmin1,ZHENG Yixing1,*()   

  1. 1. The Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, Yunnan 650224, China
    2. Nanjing Forestry University, Nanjing, Jiangsu 210037, China
  • Received:2020-01-15 Revised:2020-02-18 Online:2020-11-25 Published:2020-12-23
  • Contact: ZHENG Yixing

Abstract:

In order to reveal the response of Azadirachta indica seedling growth and metabolism to different water and light conditions, a greenhouse pot experiment covering twelve combinations with four water levels (60%-65%,40%-45%,30%-35% and 20%-25% of field capacity, respectively) and three light levels (100%, 75% and 50% of full sunlight, respectively) was set up to analyze the indicators of growth, pattern, physiological and the content of azadirachtin. The results showed that natural light and field capacity of 60%-65% were more favorable for the growth of A. indica seedlings while the height, diameter, biomass and the growth of leaves of A. indica seedlings were inhibited by drought stress and shading, and the inhibition degree of shading was significantly higher than that of drought. Under drought stress conditions. A. indica could improve drought adaptability by increasing the root--stem ratio and synthesizing a large number of primary metabolites, such as soluble proteins, free proline and soluble sugars and so on. Under shading conditions, the synthesis of soluble protein, free proline and soluble sugar were blocked; meanwhile, the content of azadirachtin was reduced. Under severe drought stress, shading could alleviate the negative effects of drought on the growth of A. indica, which followed the above-ground facilitation hypothesis and didn’t support the independent influence theory. It was concluded that A. indica had a wide range of drought adaptation and strong dependence of light in the growth stage of seeding; therefore, the maximum intensity of the light should be provided during seeding breeding. In addition, proper drought stress under sufficient light conditions was beneficial to the accumulation of primary and secondary metabolites in A. indica, which could be a potential measure to increase the content of azadirachtin in production.

Key words: Azadirachta indica, shading, drought stress, growth, azadirachtin

CLC Number: