Investigation Of Physiological Characteristics Influenced By Nitrogen, Calcium And Boron In Broccoli (Brassica Oleracea L. Var. Italica Planch)

The effects of N, Ca and B on growth, antioxidative enzymes, nutrient uptake and quality in brassica oleracea L. var. italica Planch were studied. The main results as follows:1. The effect of N and Ca on head quality, nitrate, nutrient content and carbohydrate in broccoliWhen the dose of N application increased from 10 to 20 Kg·667m-2, the appearance quality was improved and the nitrogen content was increased, but the contents of boron, calcium, total sugar, sugar, and sucrose were decreased. Topdressing nitrogen on bolting stage improved the appearance quality, increased the contents of nitrate, boron, and calcium, and decreased the contents of total sugar, reducing sugar and sucrose. Application of calcium improved the appearance quality, increased the contents of nitrogen, boron, calcium, total sugar, reducing sugar and sucrose in flower stems, and decreased the N content in flower buds.2. Investigation on "stem crack" in broccoliB deficiency induced a physiological disorder "stem crack" in broccoli. The B content in the plant of "stem crack" was lower than that in normal plant, N/B ratio in the plant of "stem crack" was obviously higher than that in normal plant. Excess N in plant increased the occurrence of "stem crack". Different broccoli cultivars have various resistance to B deficiency.3. The effect of Ca on growth, antioxidative enzymes, nutrient uptake in broccoliThe plants of Ca deficiency didn't show obvious symptoms, two plants had necrotic and perish in stem. Ca deficiency inhibited top growth in broccoli, and reduced output. Application of Ca increased chlorophyll in bud and dry matter content in head, and improved the appearance quality. Ca deficiency decreased APX, CAT, SOD activity, but increased POD activity. APX, CAT and SOD activity in stem was lower than in bud. Ca promoted B uptake in broccoli. With the increase of Ca content, calcium use efficiency decreased, and calcium uptake amount increased obviously. The Ca use efficiency of Wanshengshenglu was higher than Luxiong 90. With the increase of Ca content, K, Mg, P content increased in broccoli plant.4. The effect of B on growth, antioxidative enzymes, nutrient uptake in broccoliB deficiency inhibited top growth in broccoli, reduced head output. Fertilizer application increased broccoli output, chlorophyll content in bud and dry matter content in head. "Stem crack" was induced by B deficiency. Various genotypes had different sensitivity and...