小分子有机酸钾对水稻种子萌发和幼苗生长的影响

【目的】施用小分子有机酸钾是促进水稻生长和提高水稻产量的重要措施之一。本试验研究了3种小分子有机酸钾在不同浓度下对水稻种子萌发和幼苗生长的影响，为促进水稻增产及研发新型肥料增效剂提供理论依据。【方法】以水稻种子‘临稻21’为试验材料进行了种子萌发试验和水培试验。以不含钾盐处理为空白对照 (CK)，供试钾盐包括硫酸钾 (IOS)、甲酸钾 (OSA)、乙酸钾 (OSB) 和丙酸钾 (OSC)，设两个K+浓度分别为0.25和0.50 mmol/L。将种子置于25℃培养箱中，培养至两叶一心时，转入含有不同浓度钾盐的营养液中进行12 h光照/12 h黑暗、25℃恒温处理，至水稻幼苗长到四叶一心时，测定幼苗生长、根系形态和光合特性。【结果】1) 小分子有机酸钾促进了水稻种子提早萌发，培养48 h后，当K+浓度为0.25 mmol/L时，OSA-1和OSB-1较IOS-1水稻发芽率显著提高35.6%和37.8%；当K+浓度为0.50 mmol/L时，OSA-2和OSB-2较IOS-2水稻发芽率显著提高34.0%和27.7%；2) 与IOS相比，OSA-1、OSA-2和OSB-1显著促进了水稻幼苗叶片的宽度和鲜重的提高，并使水稻幼苗根重、总根长、根表面积和根体积显著提升；3) 与IOS处理相比，OSC处理提高了水稻幼苗叶片叶绿素含量，OSA和OSB处理显著提高了水稻幼苗叶片净光合效率、气孔导度和蒸腾速率；4) 施用小分子有机酸钾能够提高水稻幼苗根系活力，进而促进了水稻幼苗对钾素的吸收，OSA-2和OSB-2处理幼苗全钾含量较IOS-2显著提高19.6%和28.3%。【结论】与硫酸钾相比，甲酸钾、乙酸钾和丙酸钾3种小分子有机酸钾处理可促进水稻种子提前萌发，促进水稻幼苗的生长、光合效率的提高以及对钾素的吸收，以0.25 mmol/L甲酸钾 (OSA) 的促生效果最好。

Effects of small molecule organic sylvites on seed germination and seedling growth of rice (Oryza sativa L.)

【Objectives】Applying small molecule organic sylvite is one of the measures to promote rice growth and production. This study investigated the effects of three small molecule organic sylvites on rice seed germination and seedling growth at different concentrations.【Methods】Germination and hydroponic experiments were conducted using rice cultivar Lindao 21 as tested material. Three small molecular organic sylvites of potassium formate (OSA), potassium acetate (OSB) and potassium propionate (OSC) were used as treatments and potassium sulfate (IOS) as control. The concentrations of K+ in the nutrient solution were 0.25 mmol/L and 0.50 mmol/L. Rice seeds were loaded on paper, which was soaked in treatment solutions, for germinating at 25℃. Rice seedlings at 2-leaves-one-sprout stage were transformed into treatment solutions and cultured at 25℃ and 12 h light/12 h dark. At 4-leaves-one-sprout stage, the seedlings were harvested for the measurement of growth, root morphology and photosynthetic characteristics.【Results】Small molecule organic sylvite promoted the early germination of rice seeds. At 48 h, the germination rates of OSA and OSB were respectively 35.6% and 37.8% higher than that of IOS in the K+ concentration of 0.25 mmol/L, and 34.0% and 27.7% higher in the concentration of 0.50 mmol/L. Compared with IOS, OSA at 0.25 and 0.50 mmol/L, and OSB at 0.25 mmol/L significantly increased the leaf width and fresh weight of rice seedling, and significantly increased the root weight, total root length, root surface area and root volume of rice seedling. Compared with IOS, OSC increased the chlorophyll content in leaves, while OSA and OSB significantly increased the net photosynthetic efficiency, stomatal conductance and transpiration rate of rice seedling leaves. The small molecule organic sylvite could improve the root activity of rice seedlings, and promote the absorption of potassium in rice seedlings. At 0.50 mmol/L of K+ treatment concentration, the total plant K contents in OSA and OSB were significantly increased by 19.6% and 28.3% compared with IOS.【Conclusions】Compared with potassium sulfate, potassium formate, potassium acetate and potassium propionate could promote the early germination of rice seeds, the growth of rice seedlings, the photosynthetic efficiency and the absorption of K, and the best effect is from 0.25 mmol/L potassium formate.