^(60)Co-γ辐照蓝莓钙形态和亚细胞钙分布对果实硬度的影响

为了确定辐照处理后钙形态和亚细胞钙分布变化对冷藏蓝莓果实硬度的影响,本研究采用0.5、1.5、2.5 kGy辐照剂量处理蓝丰蓝莓,以未辐照处理为对照(CK),研究不同辐照剂量对果实硬度、果肉总Ca含量、不同溶解性Ca含量和Ca在亚细胞分布的影响,以及上述指标与冷藏蓝莓果实硬度的相关性。结果表明,0.5 kGy辐照处理对冷藏蓝莓果实钙的溶解性及其在亚细胞的分布没有影响,1.5和2.5 kGy辐照处理能够使蓝莓果实水溶性Ca含量升高,HCl溶性Ca和HAc溶性Ca含量下降,促进细胞器Ca^(2+)流向细胞质,并在冷藏期间逐渐向NaCl溶性Ca转变,被细胞壁吸附且累积,其中1.5 kGy辐照引起的钙形态和亚细胞钙分布变化与冷藏蓝莓果实硬度无关,但2.5 kGy辐照处理能够有效促进胞内Ca^(2+)向细胞壁迁移,对冷藏蓝莓果实硬度产生积极影响。本研究结果为蓝莓辐照保鲜研究提供了新思路。

喷施钙对肥城桃果活性钙含量及其在亚细胞分布的影响

【目的】肥城桃是山东特产,但经常发生缝合线褐变、不耐储藏等问题,补充钙肥是减轻其生理病害的有效措施。了解肥城桃的需钙规律,为肥城桃补充钙素营养提供理论依据和技术指导。【方法】以11年生红里肥桃为试材,从花后一个月开始,每隔30 d在选取的肥桃果树上喷施钙肥。试验设3个处理:1)喷施0.5%氨基酸钙溶液;2)喷施0.5%硝酸钙;3)喷施清水为对照。从4月28日起每隔30 d采样,测定果皮、果肉、果核、果仁总钙含量及果肉钙组分含量,在成熟期取果实用透射电镜观察果肉细胞内钙的亚细胞分布。【结果】3个处理果实中的钙含量均以幼果期最高,随着果实的成熟,全钙、水溶性钙、果胶酸钙含量均呈下降趋势,喷钙处理在一定程度上提高了果皮、果肉、果核及果仁的总钙含量,其中果肉总钙含量变化最明显,在果实成熟期,喷施氨基酸钙及硝酸钙的处理果肉总钙含量分别增加了68%、77%。通过电镜观察,喷钙果肉细胞中钙均匀分布于细胞壁、细胞膜、液泡膜上,液泡中有钙的堆积;未喷钙细胞壁中钙的分布减少,细胞膜、液泡膜上钙也均匀分布;发生褐变的果肉细胞内钙分布很少且不均匀。【结论】肥城桃果实中全钙含量随着果实生长而迅速下降。喷施钙肥能提高果实全钙尤其是水溶性钙及果胶钙的含量,增加细胞壁钙的分布,有利于缓解果实发育过程中钙含量的下降。喷施氨基酸钙和硝酸钙都能增加肥城桃果肉的不溶性果胶含量,提高果实硬度。

Study on Effects of Calcium on Photosynthetic Characteristics and Its Subcellular Distribution in Rice at Seeding Stage

Using the cultivars with high and low calcium in brown rice as tested ma- terials, the effects of calcium on photosynthetic characteristics and its subcellular dis- tribution in different rice cultivars at seedling stage were investigated with hydrocul- ture method. The results showed that the photosynthetic rate in leaves of high cal- cium cultivar was higher than that low calcium cultivar. The calcium content in leaves of rice was higher than that in roots. Among various tissues and organs, the calcium contents ranked as cell wall〉ribosome and intracellular soluble components〉 plastid （or chloroplasts）〉mitochondria〉nucleus. Cell wall is the most important distri- bution place for calcium, while calcium is rarely distributed in nuclei or mitochon- drias. In all the organelles, the calcium concentrations were all increased with the increased treatment concentration of calcium, especially in high calcium cultivar. The high calcium treatment showed more significant effects on calcium contents in im- portant organelles of high calcium cultivar, so it is speculated that the high calcium cultivar had higher calcium accumulation and tolerance capacities.