Effects of Calcium to Phosphorus Ratio on Seed Germination and Seedling Growth of Lolium multiflorum

In order to reveal the adaptation mechanism of Italian Ryegrass to high levels calcium and low levels of phosphorus environment in karst habitat, nine different ratios of calcium and phosphorus were set. The changes in the seed germination indexes and seeding growth indexes of ryegrass under different calcium and phosphorus ration were analyzed, and the ratios of calcium and phosphorus suitable for the seed germination and seeding growth of ryegrass was screened by the comprehensive evaluation of subordinate function. The results showed that the different calcium and phosphorus ratios had no significance effect on the relative moisture content of shoots and roots(p>0.05). Compared to shoots, it had greater inhibitory effect on roots. When the Ca concentration was10 mmol/L, the germination rate, germination index, vigor index, germination potential, root length(RL), shoots length(SR) and SL/RL, the fresh weight and dry weight of shoots and the fresh weight of roots decreased at first and then increased, while relative salt injury rate and root dry weight increased at first and then decreased and rootshoot ratio was increased with the increase of P concentration. When the P concentration was 5 mmol/L, rootshoot ratio was increased, and the germination rate, germination potential, germination index, vigor index, shoot length, root length, the fresh weight and dry weight of shoots at first decreased and then increased, at last decreased by the increase of Ca concentration. Through the comprehensive evaluation of the membership function, the ratio of calcium and phosphorus to suitable seed germination and seedlings growth of Italian Ryegrass was 5 mmol/L∶5 mmol/L. The results of this study could provide theoretical basis for the cultivation of Italian ryegrass in the southwestern region.