Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (12): 1394-1403.DOI: 10.3773/j.issn.1005-264x.2010.12.005

• Research Articles • Previous Articles     Next Articles

Combined effects of simulated nitrogen deposition and drought stress on growth and photosynthetic physiological responses of two annual desert plants in Junggar Basin, China

ZHOU Xiao-Bing1,2, ZHANG Yuan-Ming1,*(), WANG Sha-Sha1,2, ZHANG Bing-Chang1   

  1. 1Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, ürümqi 830011, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2010-03-29 Accepted:2010-06-23 Online:2010-03-29 Published:2010-12-28
  • Contact: ZHANG Yuan-Ming


Aims The two primary limiting factors for biological activities in desert ecosystems are nitrogen and water. Our study, which examined their combined effects, can provide insight into the responses of arid ecosystems to global climate change. We selected two typical annual desert plants, Malcolmia africana and Bassia hyssopifolia to determine the combined effects of nitrogen deposition and drought stress on their growth and photosynthetic physiological responses.
Methods Three levels of N addition (0, 0.18 and 0.72 g N·m -2·week -1) and two soil watering regimes (60%-70% and 30%-40% of field capacity) were randomly provided in order to simulate nitrogen deposition and drought stress. Changes in plant growth and photosynthetic physiological traits were measured shortly before flowering.
Important findings N supply and drought stress significantly affected growth of both species. With the enhancement of N supply, we found an increase in growth parameters (including root length, root weight, leaf number, leaf area, total biomass and shoot/root (S/R)). At the same N level, increased drought stress could counteract the positive effects of N supply on plant growth. Increased N, however, could also alleviate the negative effects caused by drought stress. With the increasing N addition, we also observed increase of physiological indices (net photosynthetic rate, content of chlorophyll and soluble protein). Malcolmia africana was more sensitive to N supply and drought stress than B. hyssopifolia. The different responses of the two species may due to their different biological characteristics, such as life form. The results indicated that N and water pulses in spring in this desert would be beneficial to the growth and productivity of M. africana and B. hyssopifolia, especially for aboveground parts. Moreover, N deposition could partially alleviate the negative effects caused by drought stress during the severe dry season.

Key words: annual desert plant, biomass, drought stress, N deposition, soluble protein