J Plant Ecol ›› 2019, Vol. 12 ›› Issue (2): 358-366.DOI: 10.1093/jpe/rty034

• Research Articles • Previous Articles     Next Articles

Resorptions of 10 mineral elements in leaves of desert shrubs and their contrasting responses to aridity

Meixia Zhang1, Yan Luo2,3, Zhengbing Yan4, Jiao Chen1, Anwar Eziz4, Kaihui Li2,3 and Wenxuan Han1,*   

  1. 1 Department of Ecology and Ecological Engineering, College of Resources and Environmental Sciences, China Agricultural University, No. 2 West Yuanmingyuan Road, Haidian District, Beijing 100193, China
    2 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
    3 Research Centre for Ecology & Environment of Central Asia, Chinese Academy of Sciences, Urumqi 830011, China
    4 Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
    *Correspondence address. Department of Ecology and Ecological Engineering, College of Resources and Environmental Sciences, China Agricultural University, No. 2 West Yuanmingyuan Road, Haidian District, Beijing 100193, China. Tel/Fax: +86-010-62734113; E-mail: hanwenxuan@cau.edu.cn
  • Received:2017-12-15 Revised:2018-08-01 Accepted:2018-09-06 Online:2018-09-08 Published:2019-04-01

Abstract:

Aims

We aim to investigate variations in the resorption efficiencies of 10 mineral nutrients [i.e. nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), zinc (Zn), aluminum (Al), iron (Fe) and copper (Cu)] in leaves of desert shrubs and to explore effects of aridity on resorption efficiency of these nutrients.

Methods

Plant samples were collected from 10 sites in northern Xinjiang Uygur Autonomous Region of China. Samples of green and senesced leaves were analysed to determine concentrations of N, P, K, Mg, Ca, Mn, Zn, Al, Fe and Cu and thus the nutrient resorption efficiency.

Important Findings

The mean nutrient concentrations in the desert shrubs varied, with the stoichiometric ratio Ca:N (19.3 mg g?1):K (10.5 mg g?1):Mg:P (1.01 mg g?1):Al:Fe:Mn:Zn:Cu (4.78 mg kg?1) = 4038:2950:2199:1816:211:37:32:11:2:1 in green leaves; and Ca:N (12.6 mg g?1):Mg:K (7.6 mg g?1):P (0.56 mg g?1):Fe:Al:Mn:Zn:Cu (2.85 mg kg?1) = 5583:3710:2943:2523:178:133:119:19:3.7:1 in senesced leaves. Resorption generally occurred for six elements (N, P, K, Cu, Mg and Mn, with average resorption efficiency 47.8%, 52.0%, 38.6%, 41.0%, 12.7% and 7.89%, respectively) during leaf senescence, while the other four nutrients tended to accumulate in senesced leaves, showing averagely negative resorption efficiencies [Ca (–3.87%), Al (?57.1%), Zn (?62.6%), Fe (?89.6%)]. Aridity showed strikingly different effects on the resorption process of the 10 nutrients. Of the four elements with totally (N/P/K) or mostly (Cu) positive observations of resorption efficiency, their resorption generally decreased with aridity, suggesting that drought stress had negative effects on the resorption efficiencies of these elements. In contrast, with at least one-third observations of resorption efficiency being negative, the other elements (Mg/Mn/Ca/Zn/Al/Fe) showed generally increasing resorptive tendency with aridity, except for Zn. This research provided a systematic analysis on the large variation and contrasting responses of the resorption of multi-elements to aridity in typical desert shrubs. Our findings foster the understanding of nutrient resorption patterns of desert plants and enable us to better predict the contrastive effects of drought stress on the cycling of diverse nutrients and the consequent stoichiometric decoupling in plants of desert ecosystems.

Key words: arid region, desert shrubs, drought stress, mineral elements, nutrient resorption, stoichiometric decoupling