The Research On Biological Characteristics Of Three Species Of Xanthium In Hebei

In investigation of plant resources in Hebei, Xanthium italicum Moretti as alieninvasive plants was discovered in many places of Hebei. In order to explore itsdifferences between Xanthium sibiricum Patr and Xanthium mongolicum Kitag inHebei and provide theoretical basis for prevention, development and utilization,cultivation test was carried out in July2012. By researching the biologicalcharacteristics of three species, the following conclusions are obtained:1. Xanthium italicum Moretti is one of the invasive species, the main differenceof them (Xanthium italicum Moretti, Xanthium sibiricum Patr, Xanthium mongolicumKitag) is that the surface of Xanthium italicum Moretti ripe fruit with involucre iscovered with dense hair.2. The Primary structure of roots and stems and the anatomical structure of theleaves of three species of Xanthium have generally similar characteristics, but theindexes of drought resistance: ratio of cortex thickness to radius of root, number ofvessels in primary xylem, the average diameter of vessel in secondary xylem, ratio ofpalisade tissue to spongy tissue of leaf, density of cell in the first palisade tissue,thickness of the upper epidermis and so on have obvious differences. Bycomprehensive evaluation of membership function, Xanthium italicum Moretti asinvasive plants has strong drought tolerance. Meanwhile, the stem primary phloem ofXanthium italicum Moretti also has more developed phloem fiber. This is probablythe anatomical reason for the quick spread of Xanthium italicum Moretti in Hebei.3. Under the same cultivation conditions, three species of Xanthium all put moreenergy into the part of supporting, growth and reproduction on the ground, therebyreducing the input of the underground root system, which is the important way toensure the sexual reproduction and population diffusion. The growth cycle of thethree species of Xanthium is: Xanthium sibiricum Patr＜Xanthium italicum Moretti＜Xanthium mongolicum Kitag. The ratio of root to shoot is: Xanthium italicumMoretti＜Xanthium sibiricum Patr＜Xanthium mongolicum Kitag. 4. Results for all three species showed that net photosynthesis diurnal changecurves were single peaked, the ’midday depression’ phenomenon for photosynthesisdid not occur, and the peak was at10:00. In the high light intensity conditions,Xanthium italicum Moretti, the net photosynthetic rate, transpiration rate, stomatalconductance were significantly higher than that of the other two species, that is to say,Xanthium italicum Moretti can adapt to the environment of high temperature andstrong light intensity by improving its photosynthetic capacity and transpiration rate.In photosynthetic process, the water use efficiency of Xanthium sibiricum Patr washigher than the other two species. Considering various photosynthetic physiologicalindexes, the photosynthetic characteristics of Xanthium italicum Moretti are stronger.5. The highest oil content of three species of Xanthium fruit is that of Xanthiummongolicum Kitag (12.50%), followed by Xanthium sibiricum Patr’s (8.02%),Xanthium italicum Moretti for a minimum of2.63%.6. Integrating the biological characteristics of three species of Xanthium,Xanthium italicum Moretti as invasive plants has stronger adaptability. Specialattention and vigilance should be paid to its growing trend.