Host shoot clipping depresses the growth of weedy hemiparasitic Pedicularis kansuensis

Abstract

Root hemiparasitic plants show optimal growth when attached to a suitable host by abstracting water and nutrients. Despite the fact that damage to host plants in the wild occurs frequently in various forms (e.g. grazing), effects of host damage on growth and physiological performance of root hemiparasites remain unclear. In this study, host shoot clipping was conducted to determine the influence of host damage on photosynthetic and growth performance of a weedy root hemiparasite, Pedicularis kansuensis, and its interaction with a host, Elymus nutans. Photosynthetic capacity, tissue mineral nutrient content and plant biomass of P. kansuensis were significantly improved when attached to a host plant. Host clipping had no effect on quantum efficiency (ΦPSII), but significantly reduced the growth rate and biomass of P. kansuensis. In contrast, clipping significantly improved photosynthetic capacity and accumulation of potassium in E. nutans. No significant decrease in biomass was observed in clipped host plants. By changing nutrient absorption and allocation, clipping affected the interaction between P. kansuensis and its host. Our results showed that host clipping significantly suppressed the growth of weedy P. kansuensis, but did not affect biomass accumulation in E. nutans. We propose that grazing (a dominant way of causing host damage in the field) may have a potential in the control against the weedy hemiparasite.

N-P Fertilization Inhibits Growth of Root Hemiparasite Pedicularis kansuensis in Natural Grassland

“…Foliar concentrations confirmed previous reports that graminoids generally have lower N and P concentrations but higher C assimilation capability than forbs ( Güsewell, 2004 ), accounting for a lower [C | P,N] balance in graminoids. In contrast, higher [C | P,N] balance in P. kansuensis than graminoids was due to higher N and P concentrations and lower C concentration, which agreed with a pot cultivation showing higher mineral nutrient concentrations but lower C assimilation and above-ground biomass in P. kansuensis than its grass host ( Sui et al, 2015 ).…”

“…Pedicularis kansuensis is an annual or biennial root hemiparasite commonly found in subalpine zone of western China. This fast spreading (estimated spread rate of 3.3 × 10 3 ha year -1 ; Liu et al, 2008 ) hemiparasite has become a severe problem in many regions over the past decade, reducing forage crop productivity in grasslands up to 80% and threatening the local livestock industry ( Li et al, 2006 ; Liu et al, 2008 ; Bao et al, 2015 ; Sui et al, 2015 ). So far, no effective control strategy has been identified for this root hemiparasite.…”

Long-Distance Dispersal after the Last Glacial Maximum (LGM) Led to the Disjunctive Distribution of Pedicularis kansuensis (Orobanchaceae) between the Qinghai-Tibetan Plateau and Tianshan Region

“…In nearly twenty years, P . kansuensis has been reported to rapidly expand in population sizes and become weedy in Bayanbulak Grassland of the Tianshan Mts., which has caused great loss of herbage yield and threatened the local livestock industry [39,44]. …”

Isolation and characterization of 18 microsatellites for the invasive native Pedicularis kansuensis (Orobanchaceae)

“…And it can share markedly variation in morphology and chloroplast DNA, and can adapt to heterogenous habitats, and rapidly expand until the habitats suited. In nearly twenty years, P. kansuensis has caused great loss of herbage yield and threatened the local livestock industry because its rapidly expand in population sizes and became weedy in Bayanbulak Grassland of the TSR (Sui, Huang, Li, Guan, & Li,). And now, the terrible situation are not only been found in Bayanbulak Grassland, but also in north and east of QTP, such as Menyuan county and Xunhua county in Qinghai province (Bao et al., ).…”