The Gene Expression Mechanism Of Clonal Growth Regulation Of Hippophae Rhamnoides L.ssp. Sinensis

Hippophae rhamnoides L.ssp. sinensis was a kind of tree species which had thevital function in conserving water and soil, preventing from wind, fixating sand andnitrogen. At the same time, as a typical clonal plant, it could through sprout breedcontinuously invasion towards out of forest or to get a bigger gap in forest, then formsmarvelous spectacle of thick forestry by clonal growth. It was an excellent afforestationtree specie in arid and semiarid areas of our country. However, moisture condition wasrestrictive factors which influenced clone growth ability of plants. At present, researcheson it’s clonal growth and water relations were mainly focused on morphological plasticity,biomass allocation, photosynthetic physiology and water physiology which under differentwater conditions, but didn’t revealed the internal mechanism of clonal growth regulation.In fact, plants to adapt to drought stress, such as the morphological, physiological,biochemical and ecological changes, were all caused by the change of gene expressionunder different water stress. Therefore, this paper intended to adopt different irrigation orsoil moisture gradient forming simulation rainfall intensity gradient, including water wasshortage, suitable and too much. Through analyzing the differences in IPT gene and DREBtranscription factorsexpression under different water conditions to study the causalitybetween these differences and clone growth ability, and tried to reveal the internalmechanism of it clonal growth regulation. At the same time, through the field experimentdata analysis to set up the regression model in the population growth, reproductive capacityand irrigation intensity to find out the best irrigation intensity to provide a reference for itplantation build and sustainable management. The main results and conclusions wereintroduced as below:(1) Under the different irrigation intensities, the soil moisture content increasesignificantly with the increase of the irrigation intensity. But the organization moisturecontent changing with irrigation intensity was characterized by convex parabola, whichmean increased at first and lowered later.(2) The changes of clone growth ability along with the increas ing of irrigationintensity showed as parabola, which mean the growth of plants, reproductive cloning,cloning diffusion ability changed with the intensity of water increased at first and loweredlater. Less than the optimal irrigation intensity, the increase of irrigation water couldpromote the growth of it cloning ability. Instead, greater than the optimal irrigationintensity, increase of irrigation water could inhibit its growth. Among them, the localaverage annual rainfall which most conducive to plant tree height, ground diameter, crown growth of irrigation intensities was5.91,6.10,6.12times respectively; The most beneficialto reproductive cloning irrigation intensity for the local rainfall was5.85times; The localaverage annual rainfall which most beneficial to cloning diffusion parameter, which meanthe longest cloned organs, cloned organs, cloned organs roughness and the number oflevel1, cloned organs to the total number, irrigation intensities was6.92,7.40,6.19,6.03times respectively.(3) Total RNA from it, using DNAMAN software compare the IPT homologybetween the higher species conservative region and design primers, get purpose fragmentIPT by RT-PCR. Connected with the T-carrier and shifted into DH5α cells to clone.Sequencing results show that the total length of164bp, through homology comparison, thesequence of IPT gene homology with other plants was higher, with Medicago truncatulaIPT, Citrus sinensis IPT, Salix japonica SjIPT1and Malus x domestica IPT1a,comparability was68%,67%,69%,68%respectively. Did the double standard curverelative quantitative of IPT gene under the different water contents of organizations. Theresults showed that the IPT gene expression quantity increases with the increase ofmoisture content of plant tissue.(4) According to the cDNA sequence of it DREB transcription factors in GenBankdatabase, designed primers in the region of the conserved sequence, and did the doublestandard curve relative quantitative of DREB transcription factors under the different watercontent of organizations. The results showed that the expression of DREB transcriptionfactors decrease with the increase of moisture content of plant tissue.(5) The clone growth parameters was a positive correlation with IPT gene expressionquantity relations, which mean the clone growth points of growth, reproductive cloning,cloning diffusion ability increased with the increment of IPT gene expression. In additionto the relationship between length of the longest cloned organs, first cloned organsroughness and IPT gene expression quantity were positive correlation with significant, therelationship between other clonal growth parameters and IPT gene expression quantitywere positive correlation with very significant. Cytokinin content relationship with IPTgene expression quantity was also positive correlation with significant.(6) The clone growth parameters and the expression of DREB transcription factorswere negatively correlated relationship, which mean the clone growth of plant growth,reproductive cloning, cloning diffusion ability decreased with the increase of the amount ofDREB transcription expression. In addition to the relationship between clonal reproductive capacity and the expression of DREB transcription factors was significant negativecorrelation, the other relationship between clonal growth parameters and DREBtranscription factors were negative correlation with very significant.Comprehensive analysis of the above: irrigation intensity affected the soil andorganization moisture content. IPT gene and DREB transcription factor through theexpression quantity responded to the organization moisture content, and controlled theclonal growth ability. Under drought stress, the moisture content organization was little,IPT gene expression quantity was small, but DREB transcription factor expression quantitywas large. The ability of clone growth was restrained, the clonal growth patterns tended to"guerrilla type", which mean the plants were smaller and less, and the sparse distributionstrain was less. When the oisture was appropriate, the organization moisture content washigh. IPT gene expression quantity was large, but DREB transcription factor wasn’texpressed, and the clone growth ability got full display, the clonal growth pattern tended to"gather type ", namely the plants were larger and more, and the sparse distribution strainwas more. Too much water, the organization moisture content was little. IPT geneexpression quantity was low and DREB transcription factors expressed all over again. Theclone growth ability was restrained; the clonal growth pattern tends to "guerrilla type". Inthe process of water content changed from drought-suitable-too much water, IPT geneDREB transcription factor through regulated the expression quantity formed the clonegrowth pattern change process: guerrilla type-gathered-guerrilla type, which mean theformed the ecological countermeasure continuum with the water status. Therefore,moisture conditions change was the external factor, IPT gene and DREB transcriptionfactor expression quantity was the adjustment of the internal factors, external causethrough internal cause adjusted and controlled clone growth regulation. Eventually plantsshowed a different clonal growth pattern under different water conditions. It also showedthat: under drought stress, the clone growth ability was restrained and populationpremature aging was inevitable. But improved the moisture conditions was conduciving tothe stability and clone population persistence.