追施氮肥对饲用燕麦品种叶片生长及光合特性的影响

Effects of nitrogen topdressing on leaf growth andphotosynthetic characteristics of oat varieties

摘要:

为探究不同饲用燕麦品种对施氮量的响应差异及光合生理机制,在科尔沁沙地选择燕王、牧王、甜燕1号和牧乐思4个主栽饲用燕麦品种,于燕麦的分蘖期、拔节期、抽穗期、开花期按照15%、40%、25%、20%比例,对燕麦追施0(CK),100,200,300 kg/hm2氮肥(纯N),灌浆期测定叶面积和光合参数指标,成熟期测定产量。结果表明:追施氮肥可显著增加饲用燕麦品种的产量,随着施肥量的增加,燕王与牧王产量分别呈现先升高后降低的变化趋势,甜燕1号与牧乐思呈现逐渐升高的变化趋势,与N0处理相比,在N200氮素水平下燕王和牧王产量提高61.43%和54.23%,在N300处理下甜燕1号和牧乐思产量提高65.53%和76.89%;增施氮肥显著促进旗叶、倒二叶、倒三叶叶片生长(P＜0.05),随着施肥量的增加,燕王与牧王叶面积呈现先增加后降低的变化趋势,在N200处理下叶面积达到最大值,甜燕1号与牧乐思叶面积则呈现逐渐升高的变化趋势;施氮显著提高植物叶片蒸腾系数(P＜0.05),提高光合速率、气孔导度,降低胞间二氧化碳浓度,促进燕麦光合作用;叶面积与产量呈极显著正相关(P＜0.01);不同饲用燕麦品种对氮肥的响应程度存在明显的差异,燕王和牧王对氮肥的敏感程度强于甜燕1号和牧乐思品种,燕王和牧王的适宜施氮量是200 kg/hm2,甜燕1号和牧乐思则是300 kg/hm2。

Abstract:

This study investigated the effects of different nitrogen(N) application rates on the growth and photosynthetic physiological characteristics in four different oat varieties including Yanwang,Muwang,Tianyan No.1 and mulesi.The trial was undertaken in Horqin sandy land.Nitrogen fertilizer at a total rate of 0(CK),100,200 and 300 kg/hm2 N fertilizer(pure N) was split applied at the tillering,jointing,heading and flowering stages with a proportion of 15%,40%,25% and 20% respectively.The leaf area and photosynthetic parameters were determined at the grain-filling stage,and the yield measured at the maturity stage.The results showed that topdressing N fertilizer could significantly increase the yield of forage oat varieties.With the increasing N fertilizer rate,Yanwang and Muwang showed an initial increase followed by a decrease,while Tianyan No.1 and Mulesi showed a gradual increase,compared with the N0 treatment.The yield of Yanwang and Muwang increased by 61.43% and 54.23% under the N200 nitrogen level,and the yield of Tianyan No.1 and Mulesi increased by 65.53% and 76.89% under the N300 treatment.Increasing rate of N fertilizer significantly promoted the growth of flag leaves,second and third leaves from the top(P＜0.05).With the increasing N rate,leaf area of Yanwang and Muwang showed an initial increase followed by a decrease with the maximum value found under N200 treatment,while Tianyan No.1 and Mulesi increased leaf area gradually in response to increasing N rate.Nitrogen application significantly increased leaf transpiration coefficient(P＜0.05),photosynthetic rate and stomatal conductance,while reduced intercellular carbon dioxide concentration.There was a significant positive correlation between leaf area and yield(P＜0.01).Different oat varieties responded differently to N fertilizer with Yanwang and Muwang being more responsive to N fertilizer than Tianyan No.1 and Mulesi.The suitable N application rate was 200 kg/hm2 for Yanwang and Muwang,and 300 kg/hm2 for Tianyan No.1 and Mulesi.