Effects Of Iron-stress On The Growth And Fruit Of Two Hydroponic Strawberries

Strawberry is a perennial herb of Rosaceae family with rich nutrition and sweet flavor,which was introduced into China in the 20 th century and cultivated in most areas of the country.Hydroponics can prevent strawberries from continuous cropping obstacles and soil-borne diseases,thus it has become new trend of strawberry practiced commercially.During commercial production,strawberry leaves were found yellowing,considering that iron was an important element in chlorophyll biosynthesis,this experiment was set up to study the optimal iron concentration of the nutrient solution fit for Darselect and Sweet Charlie that are suitably cultivated in chongqing.The experiment used freezing virus-free plantlets,which were hydroponiced sheltering from the rain.The nutrient solution was improved from Yamazaki formula,and 6 iron concentrations of 0,8,12,16,20 and 24mol/L were set in 12 groups.The cultivation density was 7920 plants/mu.The two varieties were planted on February 14,2019.Experimenter collected data during February 24 to May 5 and the experiment was completed on June 12.According to the statistics of the fruit quality,yield,agronomic traits and physiological and biochemical characteristics of the two varieties,experimenter analyzed data and make comparison,referring to strawberry marketing,the following conclusions were drawn:1.The iron concentration of nutrient solution had a significant effect on the fruit size and yield of the two varieties.Under the treatment of nonferrous,both varieties had no fruit,and Sweet Charlie plants died in the flowing.Both varieties' fruit volume was the largest in the 16mol/L iron concentration nutrient solution,and the fruit volume of Darselect(width 46.9mm×length 47.5mm)was significantly greater than that of Sweet Charlie(width 35.2mm×length 41.0mm).The yield of Darselect wasgreater than that of Sweet Charlie.The yield of Darselect was the highest in 12mol/L iron concentration nutrient solution,with yield of 306.23 g per plant,25.0% higher than the lowest yield of 245.02 g per plant.The yield of Sweet Charlie was the highest in16mol/L iron concentration nutrient solution,with yield of 173.56 g per plant,20.2%higher than the lowest yield of 144.30 g per plant.In commercial production,Darselect was larger in fruit size and more productive than Sweet Charlie.The nutrient solution's iron concentration that is most conducive to the fruit size and yield of Darselect is12-16mol/L,and that of Sweet Charlie is 16mol/L.2.The accumulation of mineral elements and fruit quality was significantly affected by iron stress at different concentrations.Darselect fruits' content of VC was the highest(65.96mg/100g)in 8mol/L iron concentration nutrient solution,and the flavor was the best in 12mol/L iron concentration when the sugar-acid ratio was 11.23.Sweet Charlie fruits' content of VC was the highest(67.42mg/100g)in 24mol/L iron concentration nutrient solution,and the flavor was the best in 8mol/L iron concentration when the sugar-acid ratio was 11.01.Darselect fruit of total sugars,reducing sugar and acid content are slightly higher than the Sweet Charlie.When the iron concentration of nutrient solution was 20mol/L,the total mineral element content of the two varieties was the highest.There was little difference in fruit quality of the two varieties,and the fruits' total mineral elements content of Sweet Charlie was higher than that of Darselect.In commercial production,Darselect maximized fruit quality and mineral element accumulation when iron concentration of nutrient solution was 12-20mol/L,as for Sweet Charlie,the most suitable iron concentration was20-24mol/L.3.The iron concentration of nutrient solution also affected other agronomic characters and physiological and biochemical characteristics of the two varieties,such as petiole length,color and photosynthesis.The symptoms of plant short,leaves' loss green and yellowing were observed in the two varieties treated with nonferrous.For Darselect,when the iron concentration was 12mol/L,the leaves color was the best,the content of N,P and K in young leaves was the highest,and the fresh weight of the whole plant was the largest;when the iron concentration was 16mol/L,the photosynthetic rate was the greatest;when the iron concentration was 20mol/L,thechlorophyll content and Fe content in young leaves were the highest.For Sweet Charlie,when the iron concentration was 16mol/L,the content of N,P,K in young leaves and chlorophyll content were the highest,and the photosynthetic rate was the highest;when the iron concentration was 20mol/L,the content of Fe in young leaves was the highest,the petiole length and the number of inflorescences reached the maximum;when the iron concentration was 24mol/L,the leaves color was the best,also the fresh weight of the whole plant and the root length reached the maximum.In commercial production of hydroponics strawberry,it is suggested the iron concentration of nutrient solution set to 12-16mol/L for Darselect and 16-20mol/L for Sweet Charlie.Sweet Charlie has more content of mineral elements and ripens about10 days earlier than Darselect,while Darselect has stronger adaptability and higher yield.People could select the proper varieties to plant according to the practical demand in chongqing.