摘要:以平阳特早一年生茶树幼苗为试验材料,设置90、150、210、270 mg/L Ca2+浓度进行钙过量水培培养,研究其对茶树幼苗、新梢主要品质成分的动态影响,同时测定了根系形态的动态变化。结果表明,钙过量处理前2周,茶多酚含量在较低钙过量(90、150 mg/L)条件下增加,这可能是茶多酚作为抗氧化剂对钙过量胁迫的抗性;氨基酸含量从第三周开始表现出下降,且随着处理时间的增加,下降幅度越大;咖啡碱含量处理第一周即出现下降,随着处理时间的增加,下降幅度增大。钙过量对根系的伤害主要表现在根尖数减少和较高Ca2+浓度(210、270 mg/L)条件下,根系表面会附着一层白色黏膜抑制新根的生长。钙过量处理可直接造成茶树根系吸收根的衰亡,进而逐步影响到茶树新梢品质成分的合成。 关键词:茶树;钙过量;新稍;品质成分;根系 中图分类号:S571.1;Q493 文献标识码:A 文章编号:0439-8114(2014)17-4108-04 Dynamic Effects of Excessive Calcium on Biochemical Components in Young Shoots and Root Growth of Tea SHEN Jia-zhi,ZHANG Xin-fu,HU Jian-hui (College of Horticulture, Qingdao Agricultural University, Qingdao 266109, Shandong, China) Abstract: Ca2+ concentration was applied at 90,150,210, 270 mg/L with hydroponic method to study the effects of excessive calcium treatment on the main biochemical components in young shoots of annual Pingyangtezao tea seedlings. Dynamic changes of morphological growth of tea root were determined. The results showed that content of tea polyphenols increased at 90 mg/L and 150 mg/L of Ca2+ concentration in the first two weeks, which might be one of resistance mechanisms of tea polyphenols as antioxidant to excessive calcium stress. Contents of amino acids had a downward trend from the third week. Caffeine content appeared to decrease from the first week. The decreasing trend of content of amino acids and caffeine increased with the time extension of excessive calcium treatment. The effects of excessive calcium on roots damage were mainly focused on the decrease of root tip number. The root surface was covered with white mucosa at higher Ca2+ concentration (210,270 mg/L), which would restrain the growth of the new root. Excessive calcium treatment can directly cause the decline of tea tree absorb root, and then affect the synthesis of biochemical components in young shoots. Key words: tea tree; excessive calcium; young shoots; biochemical components; roots 对钙的存在不适应的植物称为嫌钙植物,土壤中过多的钙质(特别是碳酸钙)会妨碍其生长发育[1]。茶树是一种嫌钙植物,对钙的需求比一般作物低得多,过多的钙会造成“钙害”[2]。山东省是江北茶区产茶大省,是我国有名的优质绿茶产区。青岛市地理纬度较高,昼夜温差大,所产绿茶具有叶片厚、滋味浓、香气高、耐冲泡等特点。近年来,青岛市茶产业发展迅速,崂山、胶南、即墨等地茶园种植区域不断扩大,但我省土壤中活性钙含量普遍较高,如青岛市土壤交换性钙含量平均为4.08 g/kg[3]。王跃华等[4]研究表明,钙过量可引起光合系统膜结构的破坏,导致电子传递链受阻,茶树叶片光能利用效率降低,从而影响茶树新梢的生长,成为制约高钙土壤茶区无性系茶树种植规模扩大的关键因素。有关茶树主要品质成分在钙过量条件下的代谢情况鲜见研究。平阳特早茶树属中叶类、灌木型、特早生种,扦插繁殖成活率高,抗逆性和抗寒性强,目前在青岛及周边茶区表现良好。本试验以一年生无性系平阳特早茶树幼苗为材料,采用水培研究钙过量对其主要品质成分的动态影响,旨在探讨钙过量条件下茶树主要生化成分的代谢情况,为高钙土壤茶区发展新建茶园提供参考。 1 材料与方法 1.1 试验设计 采用水培法对一年生平阳特早茶树幼苗进行培养,培养液采用茶树水培的标准营养液配方[5],水培装置见图1。水培槽用增氧泵通气,每天通风通气8~10 h,每7 d换一次营养液。缓苗培养10 d后,分别设置标准培养液钙浓度(30 mg/L)及4个钙过量钙浓度(90、150、210、270 mg/L)的培养液对试验茶苗进行处理。5个钙浓度处理分别编号为CK、T1、T2、T3、T4,试验选用乙酸钙替代硝酸钙进行钙处理。每个水培槽设置一个处理,水培槽为蓝色不透光的长方形聚乙烯塑料箱(70 cm×45 cm×20 cm),每个水培槽定植茶苗60株(分为5组,每周采样12株),5个处理300株,3次重复,共计用苗900株。茶苗由青岛农业大学即墨茶叶基地提供,水培试验于2013年在青岛农业大学校内试验基地日光温室内进行。 茶样制备:钙过量处理7 d后开始采样,每周采样一次,连续采样5周,茶树新梢采摘标准为一芽二叶,蒸锅蒸汽杀青120 s,烘箱烘干,样品装入自封袋,于-10 ℃冰柜中保存,用于比较相同处理时间(1~5周)后,钙过量处理相对于标准营养液处理对茶苗生化成分的影响。 |