“双一流”背景下高等农业院校有机化学基础课程教学新模式的构建及实践

四川农业大学作物学入选一流学科建设,有机化学作为农林专业创新型人才培养的战略支撑,如何把握机遇,找准定位,深化有机化学基础课教学改革,为农林类学科培养基础扎实、创新意识强的优质生源是我们长期面临的挑战。以一流学科建设为导向,通过调研确立双一流建设期有机化学基础课实施性教学方案,构建有机化学立体化教学资源库,实践“兴趣培养–思维开发–自主协作学习”课堂教学模式与“基础技能–综合应用–探索创新”梯度式实践教学模式,在农学、林学、动物医学等共35个专业推广,提升创新型人才培养质量,有效支撑我校一流学科建设,为同类农林高校有机化学基础课教学提供参考。

Effects of Storage and Preservation of Postharvest Gonggan Mandarin(Citrus reticulata)Fruit Immersion in Salicylic Acid Combined with Calcium Chloride

[Objectives]To investigate the effects and mechanism of fruit immersion treatment with salicylic acid(SA),calcium chloride(CaCl_(2))solutions at different concentrations or their combinations on post-harvest preservation of Gonggan Mandarin(Citrus reticulata)fruit.[Methods]13 experiments(2 storage temperatures,3 control treatments,3 concentrations of SA solution,4 concentrations of CaCl_(2) solution and 3 combinations of SA+CaCl_(2) solution for fruit immersion treatment)were conducted for 90 d.Gonggan fruit weight loss rate,rotting rate,disease index,disease type,soluble solids and organic acids content,and the differences in the activity of six enzymes(APX,PPO,CHI,CAT,SOD,PAL)related to fruit disease resistance were detected regularly.[Results]With the increase of storage days,the weight loss rate,rotting rate and disease index increased,the content of soluble solids and organic acids decreased,the activity of APX,PPO,CHI and SOD increased,and the activity of CAT and PAL decreased.However,the increase or decrease of fruit loss at low temperature was the smallest,and the increase or decrease of fruit at natural room temperature was the largest.Gonggan fruit cleaning before storage is an effective preservation and fresh-keeping technology,but its preservation and fresh-keeping effect is far less than that of fruit immersion by SA,CaCl_(2) and SA+CaCl_(2) compound solution.The effect of fruit immersion by SA solution was greater than that of fruit immersion by CaCl_(2) solution;the best concentration of SA alone was 6.0 mmol/L,which was not significantly different from 3.0 mmol/L,but the effect of 9.0 mmol/L decreased;the best concentration of CaCl_(2) alone was 6.0 mmol/L,which was significantly better than 3.0 and 9.0 mmol/L;the optimal concentration combination of SA+CaCl_(2) compound solution for fruit immersion treatment was 6.0 mmol/L SA+3.0 mmol/L CaCl_(2).[Conclusions]The fruit immersion by SA,CaCl_(2) and their compound solutions induced the increase of activity of six enzymes related to disease resistance in Gonggan fruit,and PPO and CHI were judged to be two key enzymes based on response intensity.

Structure-based identification and pathway elucidation of flavonoids in Camptotheca acuminate

Flavonoid metabolism in Camptotheca acuminate remained an untapped area for years.A tandem MS approach was used and focused on the mining and characterizing of flavonoids in mature C.acuminate.Fifteen new flavonoids and forty-three known flavonoids,including fifteen flavone analogs,sixteen flavonol analogs,seven flavanone analogs,six chalcone analogs,four xanthone analogs,ten flavane analogs were mined and identified based on their MS/MS fragments.Fifty-three of them were firstly characterized in C.acuminate.Eight biosynthetic precursors for these flavonoids were also identified.We constructed a specific metabolic map for flavonoids according to their relative contents in the flowers,fruits,stems,and leaves of C.acuminate.Furthermore,the most probable genes involved in chalcone biosynthesis,flavonoid hydroxylation,methylation,and glycosylation were further mined and fished in the gene reservoir of C.acuminate according to their conserved domains and co-expression analysis.These findings enable us to acquire a better understanding of versatile flavonoid metabolism in C.acuminate.