Analysis On Nutritional Components Of Stellera Chamaejasme L. And Allelopathic Effects On Medicago Sativa L.

Stellera chamaejasme L. is a dominant species of degraded grassland in China, which cause the great decreases of grass species that can be used to feed animals and production in native pasture due to its overspreading. This result leads to huge economic losses to livestock production. Now often use artificial excavation or chemical defendence to control the spread of Stellera chamaejasme. However, apart from damaging the ecological environment and greatly wasting resource, traditional defendence methods are easily to bring large negative impact on people and livestocks at the same time. In this paper, making Stellera chamaejasme as materials for research, we analysed its nutritional components, through research for the allelopathy of Stellera chamaejasme to Medicago sativa and Lolium perenne, and making the the influence of root aqueous extracts of stellera chamaejasme to Medicago sativa endogenous hormone levels as the breakthrough point, studied the effects in molecular level. To explore the potential of Stellera chamaejasme as a new type of forage grass and the mechanism of widespread. The main research results are as follows:1. Main nutrients of Stellera chamaejasme were measured by using the national standard. The results showed that dry matter (89.87±0.30)%, ash content (5.59±0.62)%, tannins (0.0508±0.0037)%, crude protein (15.00±1.46)%, ether extract (3.47±0.20)%, neutral detergent fiber (39.11±0.77)%, acid detergent fiber (28.7±0.76)% and lignin (6.87±0.26)%. Among them, the contents of dry matter, crude protein, ether extract are richer than others. In addition, the types and amounts of amino acids and minerals are bountiful. Researches showed that the nutrition components of S. chamaejasme are almost equivalent to Medicago sativa. It is great potential for S. chamaejasme to be planted as forage if it can be detoxicated.2. High concentration (20 mg · mL-1) of S. chamaejasme root and stem/leaf aqueous extracts treatment can delayed germination time, reduce the final germination rate and suppresses the plant height and root length of M. sativa and L. perenne. The result of low concentration of S. chamaejasme root and stem/leaf aqueous extracts (less than 1.25 mg · mL-1) treatment didn't show significant effect on germination time of seeds, the final germination rate of M. sativa and L. perenne. On the ninth day,5?2.5 mg· mL-1 treatment groups of S. chamaejasme root and stem/leaf aqueous extracts produced significant effect on plant height of M. sativa. Each treatment group of S. chamaejasme root and stem/leaf aqueous extracts didn't conduct significant promoting effect on plant height of L. perenne. It turned out that resistance of M. sativa was more strongly than L. perenne when thry were treated with S. chamaejasme root and stem/leaf aqueous extracts. Resistance of plant heigh was stronger than root length when they were treated with S. chamaejasme root and stem/leaf aqueous extracts.3. After the treatment of S. chamaejasme root aqueous extracts, the four kinds of endogenous hormones contents of M. sativa seedlings had been changed. The results showed that the contents of gibberellic acid (GA3) reduced compared with the control groups. Especially, there were significant difference at 6 h,12 h,96 h and 120 h between the treatment and control groups. Auxin (IAA) contents is stable, there is no significant difference within 120h between treatment groups and control groups. Trans-zeatin-riboside (ZR) contents reduced compared with control groups, which meant there were significant difference at 24 h,48 h and 96 h between treatment groups and control groups. The contents of abscisic acid (ABA) increased compared with control groups, the difference was significant at 120 h. The above results showed that the treat of S. chamaejasme root aqueous extracts interfered with the normal metabolism of M. sativa endogenous hormones, thus causing changes in the state of plant growth.4. After the treatment of S. chamaejasme root aqueous extracts, the expression of key enzyme gene NCED 4 related ABA biosynthesis increased, which was extremely significantly compared with the control group at 120 h. It showed that root aqueous extracts may cause damage, making NCED 4 overexpress at the transcriptional level, to the growth of M. sativa seedlings, which caused the increasement of ABA contents. To further clarify the allelopathy molecular mechanism of S. chamaejasme.