The Regulation Of The Signal Transmission Between Leaf And Root Induced By Plant Hormones On Ryegrass Regrowth

Regrowth of forage grass can provide a reliable theoretical basis for pasturegrazing-resistant mechanism. In this study, ryegrass selected as experimental materials,through vitro culture established a complete system of tissue culture propagation thatcan provide a high quality material for regrowth of ryegrass. With repeateddefoliation-induced depletion of stored carbohydrate in vivo and the endogenoushormones changed in the regeneration process of ryegrass roots and leaves as the core,by the means of different stubble height, root pruning, shading and exogenous growthregulating agents to reveal the continuing regeneration mechanism of ryegrass. Themain results are as follows:1. In annual ryegrass "Tetra-god" tissue culture system, full seeds weredisinfected7min with0.1%HgCl2, the disinfection effect was the best; In this system,the basic medium was MS medium; Seed germination medium was MS basic medium;The stem base parts as explants for shoot induction training, selection medium was MS+6-BA2.0mg·L-1+NAA0.2mg·L-1, the effects were best; Rooting medium was MS+IBA1.0mg·L-1+NAA0.2mg·L-1, the rooting effects were best; All media wereadded sucrose30g·L-1and agar6.2-6.5g·L-1, pH5.8; The tissue culture seedlingswere transplanting to vermiculite: peat soil=3:1, the survival rate can reach more than95%.2. Compared to the roots, the stubble in storage of organic substances are closeron the leaves regeneration. Single defoliation, the low stubble and root pruningreduced leaf biomass and increased the relative regeneration index (RI) and Z+ZRconcentration of leaves. In shading, the regrowth leaves biomass in high stubble andhigh stubble with root pruning was closer, and they were significantly higher than thelow stubble. Lighting conditions, low stubble and high stubble with root pruning undersingle defoliation, or high stubble under frequent defoliation, both led to higherbiomass, total biomass index (AI), and Z+ZR concentration of leaves. In addition, Z+ZR concentration of leaves of each treatment in light experiment was directlyregulated by its delivery rates from the roots to the leaves. And leaf cytokinin inducedby root is a key factor in the ryegrass regulation in the condition of different stubbleheight.3. Added exogenous auxin or auxin inhibitors to ryegrass may promote or inhibi-t the increase of newly grown leaves biomass and Z+ZR concentration of leavescorrespondingly; Newly grown leaves biomass and Z+ZR concentration of leaves wassignificantly correlated.