幼穗分化期喷施磷钾肥对早稻抵御低温及产量和生理特性的影响

以超级杂交早稻品种淦鑫203为材料,以叶面喷清水为对照(CK),设置0.1%(P1)、0.3%(P3)和0.5%(P5)3个浓度的磷酸二氢钾以及撒施草木灰(MH)处理,研究了双季早稻幼穗分化期遭遇低温条件下喷施磷钾肥对水稻叶温、产量和生理特性的影响.结果表明: 低温期间6:00—18:00所有时间段,喷施磷酸二氢钾和草木灰的稻株叶片温度均高于CK;低温胁迫下各处理稻株叶片叶绿素含量和净光合速率均逐渐降低,以P3处理降低幅度最小;各处理抗氧化酶活性产生不同程度的变化,P3处理的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性上升幅度均高于其余处理,而过氧化氢酶(CAT)活性降低幅度低于其余处理;低温处理结束后,以CK处理的丙二醛(MDA)含量最高;低温胁迫下喷施磷酸二氢钾和草木灰处理均能不同程度提高植株干物质积累,达到减缓产量降低的效果,其中以P3处理最佳;从产量结构上看,各处理较CK每穗总粒数、结实率、千粒重均有明显改善.叶面喷施0.3%磷酸二氢钾是增强双季超级杂交早稻幼穗分化期低温抵御能力的较为实用的农艺措施.

Effects of spraying P and K fertilizers during panicle primordium differentiation stage on cold resistance,yield and physiological characteristics of early rice

Super hybrid early rice variety Ganxin 203 was used as test material, and four foliar spraying treatments were set using clear water as the control group (CK), and 3 concentrations of potassium dihydrogen phosphate (KH₂PO₄) with 0.1% (P1), 0.3% (P3), 0.5% (P5) and po-tash (MH). The effects of spraying P and K fertilizers on the leaf temperature, yield and physiolo-gical characteristics in double-season early rice under low temperature conditions during panicle primordium differentiation stage were studied. The results showed that during the low temperature period 6:00-18:00, rice leaf temperature under the different treatments with potassium dihydrogen phosphate and potash was higher than that of CK. Leaf chlorophyll content and net photosynthetic rate (P_n) of rice plants decreased gradually with the treatments under low temperature, while the reduction range was the smallest in treatment P3. The activities of the antioxidative enzymes varied to different extents, and the increase range for the activities of superoxide dismutase (SOD) and peroxidase (POD) in treatment P3 were higher than those in the other treatments. The decrease range of the activity catalase (CAT) in treatment P3 was lower than that in the other treatments. At the end of low temperature treatment, malondialdehyde (MDA) content was the highest in CK. Under low temperature, foliar spraying of potassium dihydrogen phosphate or potash could improve dry matter accumulation to varying degrees and achieve the purpose of slowing down the yield decrease, among which treatment P3 was the best. It could be found from the yield components that the total grains per panicle, seed setting rate and 1000-grain mass were significantly improved for all treatments compared to CK. The application of foliar spraying of 0.3% potassium dihydrogen phosphate was the most effective agronomic measure to enhance the resistance to low temperature during panicle primordium differentiation stage for double-season super hybrid early rice.