Tolerance of Salsify (Tragopogon graminifolius) to Simulated Herbivory

Subject Areas : Journal of Crop Ecophysiology

N. Valaie ¹ , S.Z. Hosseini Cici ²

1 - M.Sc. Student of Weed Science, Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Iran.
2 - Assistant Professor, Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Iran

Received: 2013-06-20 Accepted : 2014-09-21 Published : 2014-10-23

Keywords: Tragopogon graminifolius, Herbivory, Vegetative and reproductive growth,

Abstract :

The ability of plants to reduce the negative effects of leaf removal or simulated herbivory on their growth is defined as their tolerance. Tragopogon graminifolius is a herbaceous perennial weed distributed around the world. To investigate the effect of leaf removals like 100% leaf removal, no damage (control), 50 % leaf removal at ten- leaf stage, 50 % leaf removal at twenty- leaf stage and 100 % leaf removal at twenty- leaf stage on its survival and final biomass of this plant, a greenhouse study was conducted during 2011 in completely randomized design. The results showed that the number of active leaves, number of flowers and seeds, number of branches and final height of T. graminifolius were significantly lower in “100% leaf removal at twenty-leaf stage” (P < 0.0001) less than the other treatments. These results indicate that herbivory or reduction of the photosynthesing leaves, reduce plant's ability to survive and produce reproductive organs. Furthermore, the intensity and timing of the mid-term leaf removal resulted in negative effects on seed yield and the reproductive growth of this weed more than ”100% leaf removal at twenty- leaf stage” treatment by 66.7% compared to control. Shoot and root biomass in “100 % leaf removal at twenty-leaf stage” treatment was 52.58% and 52.06% less than the control one, respectively (P < 0.0001). Also, our results show that population of this perennial weed, despite its tolerance of damage, is not able to compensate its tissue losses. This finding, because of the stability of this plant in disturbed habitats, is of ecological significance.