Effects Of Stem Fragmentation,Dehydration And Water Extract Of Leaves Of Broussonetia Papyrifera On Vegetative Propagation Of Alternanthera Philoxeroides

Biological invasion is one of the most serious environment promblems that human face in the 21st century. With the integration of global economy, people gradually realize that biological invasion is harmful to the ecological environment, social economic, human health and the harmfulness is becoming more and more serious because of the influence of human activities and global climate changes. Alternanthera philoxeroides is one of malignant weed and impact the production of industry and agriculture as well as people’s daily life during its continuous spreading. Vegetative propagation is the main reproductive pattern of Alternanthera philoxeroides. And also, it is the main reason why we feel difficult to control this kind of weed. Doing more intensive research on the characters of this weed’s propagation will be significantly important for understanding its invasion mechanism and exploring effective control measures. We investigate the influence of stem segmentation, drought stress and Broussonetia papyrifera leaves’ water-logged extraction solution on this weed’s propagation and the growth of regenerating strains, using the erect stem, the ground stolons and the rhizomes of the weeds living in two kinds of habitat (the aquatic environment and the terrestrial one) as the experimental materials, and obtained the following results:1. The segmentation has promoting effect on the budding rate of the weed’s stems. The erect stem, the ground stolons and the rhizome first part of the budding rate of the weed living in two environments are higher than the related third and forth part. There are no evident disparities among the budding rate of the weeds living in two habitats which have same amount of stems those are in different parts. The segmentation has inhibiting effect on the regenerated plants of the weed’s stems, the ramet in the forth part grows better than the one in the first part. The main symptom is that the former’s some parameters such as the height, the average number of nodes, the length of nodes, the leaves’number, the biomass exceed the latter’s. Having compared with stem segmentation of the weeds in different habitats, no obvious differences are found among the budding rate and the morphological parameters of regenerated plants in the same nodes of the erect stem and the ground stolon, the rhizomes in the aquatic environment’s has stronger vegetative propagation ability than the terrestrial environment’s.2. As the dehydration degree increases, the budding rate of three kinds of stems in both environments decreases step by step, dehydration to fresh weight the 25 percent treatment group of terrestrial and aquatic type stem segment of the budding rate lowest were 0.015 each node (rhizome with four segment of terrestrial) and 0.015 each node (ground stolons with three segment of aquatic) respectively, significantly lower than their respective control group of 0.127 each node and 0.09 each node. Drought stress can effectively restrain the growth of Alternanthera philoxeroides’ regenerated plants. And also, most of their parameters are trending down such as the height, the average of nodes, the length of nodes, the leaves’ number, the leaf relative water content, the biomass and the chlorophyll content. Having compared with the morphological parameters of regenerated plants of the weeds in different habitats, it shown that all treatment groups’ramets of the forth stem in the erect and ground stolon (in the terrestrial environment) are pretty taller than that (in the aquatic environment). The third stems of ramet of the erect stem and ground stolon in the terrestrial environment are significantly longer than the aquatic ones. The ramet of the terrestrial type of Alternanthera philoxeroides to drought stress has stronger adaptability.3. The water-logged extraction solution of Broussonetia papyrifera leaves has some allelopathic inhibition effects on the budding of Alternanthera philoxeroides. It is able to reduce the budding rate, and cut down the quantity of budding plants. The solution concentration of 0.3 g/ml treatment group of terrestrial and aquatic type stem segment of the budding rate lowest were 0.015 each node (erect stem with four segment of terrestrial type) and 0.013 each node (rhizome with three segment of aquatic type) respectively, significantly lower than their respective control group of 0.08 each node and 0.127 each node. The water-logged extraction solution of Broussonetia papyrifera leaves inhibits the Alternanthera philoxeroides’ regenerated strains, main symptoms are suppressing the new plants’ height, the average of nodes, the length of nodes and the growth of leaves, lowering their biomass and reducing the amount of leaf relative water content and chlorophyll content. Different concentrations of Broussonetia papyrifera leaf water extract treated, no obvious differences are found among the budding rate and the morphological parameters of regenerated plants in the same nodes of the terrestrial and aquatic type, indicates that in this study set the concentration and time range, the water extract of Broussonetia papyrifera leaves in two habitats of stem segment of vegetative reproduction with similar allelopathy.