Biodiv Sci ›› 2013, Vol. 21 ›› Issue (5): 590-600.DOI: 10.3724/SP.J.1003.2013.11044

• Orginal Article • Previous Articles     Next Articles

Reproductive characteristics of the invasive species Solanum rostratum in different habitats of Xinjiang, China

Juan Qiu1, Dilinuer Shalimu1,2, Dunyan Tan1,*   

  1. 1 Xinjiang Key Laboratory of Grassland Resources and Ecology & Ministry of Education Key Laboratory for Western Arid Region Grassland Resource and Ecology, College of Grassland and Environment Sciences, Xinjiang Agricultural University, Urumqi 830052
    2 College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083
  • Received:2013-02-20 Accepted:2013-07-01 Online:2013-09-20 Published:2013-10-08
  • Contact: Tan Dunyan

Abstract:

The invasiveness of alien plants is closely related to their reproductive characteristics. A comparison of reproductive characteristics of an alien species in different habitats will help to reveal its optimum habitat for invasion and the mechanism of invasion. Furthermore, it will provide a theoretical foundation for planning a reasonable management strategy. Solanum rostratum is a summer annual weed native to the neotropics and the southwestern USA that produces offspring only by sexual reproduction. This species has become established in seven provinces/cities of China, including Xinjiang. We compared reproductive characteristics of S. rostratum in oasis, desert grassland and gravel desert habitats in Xinjiang and determined the optimum habitat for its invasion. The results were as follows. (1) Single-flower duration of S. rostratum was between 27 and 47 hours. Daily flowering time and single-flower duration were similar among the three habitats. However, number of flowers per individual differed among habitats (P<0.01=: oasis > desert grassland > gravel desert. (2) Halictus quadricinctus, Halictus sp. and Xylocopa latipes were the pollinators of S. rostratum, and all of them buzz-pollinated flowers. However, X. latipes visited flowers only occasionally. (3) Total visiting frequency of pollinators differed among habitats (P<0.05): oasis > desert grassland > gravel desert. Halictus quadricinctus preferred habitats with relatively low temperatures and high humidity, while another species of Halictus preferred relatively high temperatures and low humidity. Thus, the daily time of the peak of visiting frequency of H. quadricinctus was earlier than that of Halictus sp. (4) Order of number of fruits per individual, seed number per fruit and per individual and mass of 1,000 seeds was oasis > desert grassland > gravel desert. Fruit number per individual was highly significantly positively correlated with both number of flowers per individual and total visiting frequency of pollinators. Seed numbers per individual and per fruit were significantly positively correlated with total visiting frequency of pollinators. Our study indicates that S. rostratum can obtain more resources, produce more flowers that attract pollinators and produce more seeds with larger mass in oases than in desert grassland or gravel desert. Therefore, the oasis is the optimum habitat of S. rostratum in the arid region of Xinjiang, China.

Key words: flowering, fruit and seed set characteristics, invasive species, pollinator, Solanum rostratum, Xinjiang