The Effects And Preliminary Research Of The Molecule Mechanism Of Elevated CO₂ On The Growth And Development Of Fruits And Vegetables

Elevated CO2 concentration can stimulate the growth and development of most vegetables in the greenhouse,but the molecular effects of different crops and the response of different crops to CO2 are not well understood.In this study,six eggplant varieties and two watermelon varieties of melon and fruit vegetables were selected as experimental materials.The physiological and photosynthetic characteristics of CO2 were observed and analyzed by transcriptomics.The results are shown as follows:?1?Elevated CO2 can promote the growth of some eggplant varieties and watermelon varieties.Compared with the control,there was no significant change for the growth of eggplant variety No.6.The plant height,stem diameter and plant width of the other eggplant varieties were increased by 30%,20% and6% respectively,and only the plant height,stem diameter and plant width of variety No.5 were improved in each observation perid;In the period of seeding,The plant height and leaf length of the 'Kenong No.3'and 'Kenong No.5' watermelon were increased by 8.57% and 1.67% respectively,and In the period of stretching maximum increased of plant height,leaf length and leaf width reached 8.14%,17.86% and25%.?2?Elevated CO2 can improve the quality of eggplant and watermelon fruit.Compared with the control,the soluble protein content of eggplant varieties No.3 and No.5 was increased by 6.9% and 15.25%,respectively.The content of organic acid and soluble total sugar of 'Kenong No.3' in watermelon variety was increased by 17.71% and 124% respectively;The content of organic acid and soluble total sugar of Kenong No.3' and'Kenong No.5' were increased by 17.71% and 39.30%? 124% and 107%,respectively.?3?Elevated CO2 can enhance the plant photosynthesis.The response of 6 eggplant varieties to CO2 was different.The CO2 saturation point and compensation point of variety No.5 were higher than other varieties,which were 1565.4?mol·mol-1 and 67.2?mol·mol-1 respectively,and the CO2 saturation point and compensation points of variety No.1 were the smallest,which were 529.2?mol·mol-1 and33.6?mol·mol-1 respectively.After elevated CO2,the light saturation point and net photosynthetic rate ofeggplant leaves was increased by more than 20%,and the light compensation point was decreased by at least 10%.?4?Comprehensive analysis found that eggplant variety No.5 was more sensitive to CO2 response.Further analysis of eggplant No.5 transcriptomics was revealed 169 differentially expressed genes?99up-regulated and 70 down-regulated?.These genes mainly involve transcription factors and various enzymes.The expression of bilirubin deaminase gene Sme2.5₀4464.1_g00001 in chlorophyll porphyrin pathway and malic dehydrogenase gene Sme2.5₀3383.1_g00002 in carbon metabolism are up-regulated after elevated CO2.Elevated CO2 can change photosynthetic efficiency by altering the expression of related genes such as carbon fixation and metabolism,chlorophyll synthesis,and ultimately promote plant growth.At last,12 genes were further detected by q RT-PCR.10 of them were consistent with the sequencing results,which showed that the analysis results were reliable.In conclusion,elevated CO2 can promote the growth and development of Eggplant and watermelon,and improve the nutritive quality of fruit.In summary,the above conclusions provide a theoretical basis for CO2 fertilization technology in greenhouse melon and fruit vegetable cultivation.