Effect of soil nutrient, neighbor identities and root separation types on the intra- and interspecific interaction among the three clonal plant species

7 May 2019

Jaafry, Syed; Dezhi, Li; Zhihua, Fan; Liu, Lu; wei, Xiaoyu; Yang, Tingjun; Sun, Yuming; Zhu, Yingyang; Li, Lingling; Ren, Zixing; Kong, Rongpei

In natural environments, plants frequently interact with both heterospecific and conspecific neighbors. Intensity The intensity of belowground plant interaction with neighboring species usually varies with the availability of soil nutrients in the habitats. According to the classical ecological theory, competition between the conspecific neighbors may occur more severely due to similar nutrient requirement, especially when the nutrients are scarce in the habitat., Hhowever, many recent studies presented the opposite findings, and also gave the alternative mechanism of species recognition instead of classical ecological theory. Taking Zoysia sinica as focal species, we conducted a controlled experiment to test the response of intraspecific and interspecific interactions among the three clonal species (Zoysia sinica, Zoysia japonica and Alternanthera philoxeroides, which was the conspecific, close stranger and distant stranger to focal species, respectively) at different root treatments (no separation NS, clone separation CS and ramet separation RS) and low and high, two nutrient levels. Results showed that Z. sinica recognized its neighboring conspecific at NS and CS treatments, and did not show above and belowground competition at both low and high nutrient levels. Performance of focal plant (Z. sinica) was more facilitated when it was grown with its conspecific neighbor, as compared with all other types of neighbors, whereas, the competition was more intense when Z. sinica grown with its close stranger (Z. japonica), as compared with its distant stranger (A. philoxeroides) in all root separation treatments. Generally, competition between plants was intense atwhen there was a high nutrient level as compared with to a low nutrient level, suggesting that both soil nutrient and species recognition mechanism play a significant role in the intra- and interspecific interaction and fitness of these three neighboring clonal species.