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低温寡照影响番茄幼苗根系有机酸代谢和养分吸收

花匠小妙招
2025-05-02 13:27

摘要：

低温寡照气象灾害严重制约设施番茄产量和品质，本研究拟从番茄根系有机酸代谢和养分吸收的角度，探究低温寡照影响番茄生长的潜在机制。通过人工控制试验，设置不同低温（最高温/最低温：12℃/2℃、14℃/4℃、16℃/6℃、18℃/8℃）和弱光（200、400μmol·m-2·s-1）的交互处理，研究低温寡照处理2、4、6、8、10d后苗期番茄根系活力、氮磷钾含量、植株干重以及根系分泌低分子量有机酸（LMWOAs）的动态变化。结果表明：低温寡照显著抑制番茄根系活力和氮、磷、钾吸收，抑制根、茎叶干重增加，温度越低抑制作用越强；最低温（12℃/2℃）和最弱光（200μmol·m-2·s-1）处理下，番茄根系活力仅为对照的7.70%～22.1%，根系氮、磷、钾的净吸收量分别为对照的3.75%～18.1%、1.28%～27.1%和19.1%～35.5%，根系、茎叶干重分别为对照的23.4%～55.9%和42.6%～66.5%。低温寡照胁迫下番茄根系分泌低分子量有机酸的总量显著降低，土壤pH值升高，其中草酸的分泌量最大，下降幅度最明显。表明低温寡照对番茄生长的抑制作用可能与根系活力下降，草酸分泌减少和养分吸收降低有关，推测在低温寡照胁迫初期施加适量草酸或氮、磷、钾复合肥料或许可提高番茄的抗灾能力。

关键词: 低温寡照, 番茄, 根系活力, 土壤养分, 有机酸

Abstract:

Combined low temperature and low irradiation(LTLI) conditions seriously affect the yield and quality of tomato, the present study aimed to clarify the underlying mechanisms through investigating the changes of organic acids metabolism and nutrients uptake in tomato root. A pot experiment in artificially controlled environments was conducted to study the dynamic changes of root activity, nitrogen(N), phosphorus(P), and potassium(K) uptake by the root, dry weights of the root and shoot, and the secretion of low-molecular-weight organic acids(LMWOAs) by the root, under different LTLI conditions (maximum/minimum temperature: 12/2℃, 14/4℃, 16/6℃, 18/8℃; weak irradiation: 200, 400μmol·m-2·s-1). Results showed that the LTLI strongly inhibited the root activity, net absorption of N, P and K, and dry weights of the root and shoot, and the effects were enhanced with the decrease of temperature. Under the condition of 12/2℃ and 200μmol·m?2·s?1, the root activities were 7.70%-22.1% of the control, net absorption of N, P and K in the root were 3.75%-18.1%, 1.28%-27.1%, and 19.1%-35.5% of the control, respectively, dry weights of the root and shoot were 23.4%-55.9% and 42.6%-66.5% of the control, respectively. The LTLI also inhibited the secretion of LMWOAs and increased the soil pH, oxalic acid was the main acid which decreased most obviously. This study indicates that the inhibition of the LTLI on the growth of tomato seedling was related to the decrease of root activity, secretion of oxalic acid, and the nutrients uptake. Therefore, suitable application of oxalic acid or complex fertilizer (including N, P, K) at the initial stage of the LTLI occurrence, may enhance the resistance ability of tomato seedling to the LTLI.

Key words: Low temperature low irradiation, Tomato, Root activity, Soil nutrient, Organic acid