The Influence Of Humic Acid Conditioner On Seedling Growth And Yield In Wheat And Rice

Wheat and rice are two major crops in China, and the yield of which is always one of the focus. As an organic growth conditioner, humic acid has multiple physiological effects in plants, such as enhancing photosynthesis, improving the utilization rate of fertilizer, promoting stress resistance, stimulating plant growth, and so on, so it is popular in agricultural application.In this experiment, the seedlings of japonica rice (Oryza sativa L. subsp. Japonica) Huaidao 5, indica rice (Oryza sativa L. subsp. Indica) Yangdao 6 and wheat (Triticum aestivum L.) Yangmai 5 were used, and treated with different dilutions of humic acid conditioner, to study the effects on seedling biomass, root activity, soluble sugar content, antioxidant enzymes (SOD, POD,CAT) activity, chlorophyll content and so on. Then in the field, treated with humic acid conditioner, the soluble sugar content, antioxidant enzymes (SOD, POD, CAT) activity, chlorophyll content, chlorophyll fluorescence parameters in flag leaves, and grain weight, grain number per panicle and grain starch and soluble sugar content were determined. In addition, the Illumina HiSeqTM 2500 high-throughput sequencing technology was used, to analyze the transcriptome sequencing of rice and wheat seedlings after humic acid treatment.. The main results were as follows:1.The seedling height, fresh and dry weight, root length and root activity were all improved in different extent after treated with humic acid conditioner. With the increase of concentration, the facilitating effect increased firstly and then decreased, and the most effective concentration for Yangmai 5, Yangdao 6 and Huaidao 5 was 500 ×,1000x,1500 × dilution times, respectively.2. The soluble sugar content and the activities of SOD, POD, CAT in seedling leaves decreased differently, and the most effective concentration for Yangmai 5, Yangdao 6 and Huaidao 5 was also 500 ×,1000× and 1500 × dilution times respectively.3. After treated with humic acid conditioner in the field, the chlorophyll content and chlorophyll fluorescence parameters in flag leaves of wheat and rice were promoted in different extent, and the most effective treatment was naphthylacetic acid and humic acid together. In addition, the conditioner could lower the soluble sugar content, antioxidant enzyme (SOD, POD, CAT) activities in flag leaves in different degrees, and the effect of naphthylacetic acid and humic acid together was the best.4. After treated with humic acid conditioner in the field, the grain number per panicle, grain weight, starch and soluble sugar content in grains were all increased differently, and the most effective treatment was naphthylacetic acid and humic acid together.5. Through high-throughput transcriptome sequencing, From gene expression results, 1472and 2606 differential expression genes were screened in rice and wheat, respectively, from which,749 genes were up-regulated and 723 genes were down regulated in rice,1813 genes were up-regulated and 793 genes were down regulated in wheat. The GO enrichment analysis results showed that the genes in plastid, membrane and cell were the most significant difference in rice. While in wheat, the most significant difference genes were enriched in the carbohydrate metabolic process and response to oxidative stress. KEGG enrichment analysis showed that in rice seedlings, the differentially expressed genes were enriched in biosynthesis of amino acids and metabolism, etc. While in wheat seedlings, the differentially expressed genes were enriched in biosynthesis of amino acids, starch and sucrose metabolism, photosynthesis, etc.