钙对甜樱桃贮藏品质、钙形态及细胞超微结构影响

研究了氯化钙（Chlo-Ca）、螯合钙（Che-Ca）和纳米钙（Nano-Ca）对甜樱桃Cerasus pseudocerasus（Lind l.）G.Don贮藏品质及钙形态的影响,并采用焦锑酸钾沉淀-透射电子显微镜观察了不同钙处理樱桃贮藏后果肉细胞的超微结构特点。结果表明,Che-Ca处理提高了果实硬度,且有效的抑制了樱桃贮藏后硬度的降低和VC的消耗,但对果实采摘时维生素C含量影响差异不显著。3种钙处理增加了樱桃可溶性固形物的含量,对可溶性糖、可滴定酸和糖/酸影响较小。喷钙处理樱桃的全钙、水提取钙（H2O-Ca）、乙醇提取钙（ALc-Ca）的含量均有不同程度增加。樱桃果肉中的钙主要以ALc-Ca的形式存在,且Che-Ca处理中的ALc-Ca所占比例要显著高于Chlo-Ca和Nano-Ca处理。贮藏后NaCl溶液提取钙（NaCl-Ca）、H2O-Ca和ALc-Ca含量下降,醋酸提取钙（HAC-Ca）和盐酸溶液提取钙（HCl-Ca）的含量有所上升。贮藏60d后的樱桃细胞超微结构照片显示对照处理的细胞壁有断裂,细胞膜系统部分消失,细胞内较干净,且少部分细胞有收缩现象,3种钙处理,细胞壁结构比较完整,发现较多的黑色物质存在,不均衡的分布于细胞壁、细胞膜、液泡膜和线粒体等系统中。

Storage property, calcium fractions, and cell ultrastructure in sweet cherry as affected by calcium

Effects of calcium chloride（Chlo-Ca）,calcium chelate（Che-Ca） and calcium nanometer（Nano-Ca） on the storage property of sweet cherry were studied in this paper.Fractions of calcium during the storage were separated by sequent extracting method in this paper.Influences of different calcium on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improve method of potassium pyroantimonate technique.Results showed that Che-Ca could improve the fruit firmness and retard the firmness decrease during storage.Although the calcium treatments had no effects on the content of vitamin C,they could prevent VC consumption during storage effectively,especially Che-Ca treatment.Different calcium treatment showed no obvious impacts on the content of sugar,titratable acidity and the ratio of sugar and acidity but increased the content of total soluble solids.Calcium treatment significantly increased the content of total calcium,H2O-Ca and ALc-Ca content.ALc-Ca was the major fraction among all the different forms of calcium in sweet cherry fruit.Besides,in Che-Ca treatment,the content of ALc-Ca content was higher than that in Chlo-Ca and Nano-Ca treatments.The content of NaCl-Ca,H2O-Ca and ALc-Ca decreased but HAC-Ca and HCl-Ca increased at 60 days after storage.Under transmission electron microscopy,cell wall fracture,cytomembrane disappearance and cell shrinkness were partly observed in the treatment of no calcium.The structures were intact for cell wall and some black uncertain matters distributed in cell wall,cell membrane,tonoplast and mitochondriadisproportionally in all Ca treatments.