摘要: 为明确番茄穴盘苗组织钾阈值，采用四苯硼钠比浊法测定了番茄17个主栽品种不同组织钾含量，并选其中两个品种(佳红4号和中杂105号)研究了氮、磷、钾盈亏供应和外界环境因素对番茄穴盘苗组织钾含量的影响。发现17个品种中，仙客5号组织间钾含量的变化范围最大，为2.92~6.72 g/L；供试品种的10个取样组织中，第2叶位叶柄品种间钾含量的变化范围最大，为3.23~4.93 g/L。与正常对照相比，钾盈余供应下番茄穴盘苗组织钾含量最大提高了1.23倍，钾亏缺供应下钾含量最大减小了64.84%。番茄穴盘苗组织钾含量也会因氮供应水平、磷供应水平、温度、光照等外部因素的改变而变化，最大增加了38.34%，最大减小了36.01%。以番茄17个品种不同组织钾含量范围为基础阈值，利用环境条件作用最大增幅和最大减幅进行校正，获得番茄穴盘苗组织钾含量阈值，即下胚轴4.63~6.94 g/L，茎5.56~7.40 g/L，第1叶位叶柄2.65~4.62 g/L，第1叶位叶片2.14~4.09 g/L，第2叶位叶柄2.80~6.93 g/L，第2叶位叶片2.54~5.17 g/L，第3叶位叶柄3.55~7.06 g/L，第3叶位叶片2.69~6.24 g/L，第4叶位叶柄4.29~7.71 g/L，第4叶位叶片3.90~7.07 g/L。
Abstract:
To obtain the K threshold in tissues of tomato plug seedlings, K contents were measured in different tissues of 17 tomato cultivars by turbidimetric method with sodium tetraphenylborate. The effects of N, P, K fertilization level and environmental factors on K contents were also examined in two representative cultivars (“Jiahong No.4” and “Zhongza No.105”). The results showed that K contents varied among different cultivars and tissues with significant difference. The K threshold of the second leaf petiole among different tissues was maximal and 3.23 - 4.93 g/L, and the K threshold of Xianke No.5 among different tissues was maximal and 2.92 - 6.72 g/L. In addition, the K contents of tomato plug seedlings increased as the K fertilization levels increased from 29 to 1875 mg/L. Compared to that in the seedlings supplied with normal K, the K content was increased by at most 1.23-fold in the seedlings supplied with excessive K, while in the seedlings fertilized with low level of K, the K content was reduced at most 64.84%. With the change of external factors such as N or P fertilization level, or temperature, or light intensity, the K contents in tissues of tomato plug seedlings also changed. And the K contents were increased at most 38.34% and decreased at most 36.01%. Therefore, the basic values of K contents from 17 cultivars were corrected with these environmental factors. Finally the K threshold in tissues of tomato plug seedlings was 4.63 - 6.94 g/L in hypocotyls, 5.56 - 7.40 g/L in stems, 2.65 - 4.62 g/L in first leaf petioles, 2.14 - 4.09 g/L in first leaves, 2.80 - 6.93 g/L in second leaf petioles, 2.54 - 5.17 g/L in second leaves, 3.55 - 7.06 g/L in third leaf petioles, 2.69 - 6.24 g/L in third leaves, 4.29 - 7.71 g/L in fourth leaf petioles, 3.90 - 7.07 g/L in fourth leaves.