Abstract:

In order to explore the response of yield， chloroplast content， fluorescence characteristics and photosynthetic characteristics of different forage oat varieties to nitrogen application， taking forage oat varieties suitable for planting in Kerqin sandwishes as materials， this paper studied the effect of nitrogen fertilizer on photosynthetic physiological characterics and yield of oat. Using randomized block experiment design， 4 main planting forage oat vaieties planted in the Kerqin sandwishes， Yanwang， Muwang， Tianyan 1 and Mulesi， 0（N0，CK）、100（N100）、200（N200）、300 kg·hm^-2 （N300） nitrogen fertilizer （pure N） were applied according to the proportion of 15%， 40%， 25%， 20% at the tillering stage， jointing stage， heading stage and flowering stage of oats， respectively. Chlorophyll content， carotenoid content， fluorescence parameter index and photosynthetic index were measured at grain filling stage， and yield was measured at maturity stage. Yanwang and Muwang had the highest yield under N200 nitrogen application level， which were low nitrogen and high efficiency forage oat varieties； Tianyan 1 and Mulesi had the highest yield under N300 nitrogen application level， which were high nitrogen and high efficiency forage oat varieties. With the increase of nitrogen application level， the chlorophyll content， potential photochemical efficiency （F_v/F_m）， actual photochemical efficiency （ΦPSⅡ）， photochemical quenching coefficient （qP）， net photosynthetic rate （P_n）， stomatal conductance （G_s）， transpiration rate （T_r） of different forage oat varieties showed a trend of increasing first and then decreasing or increasing. The NPQ and C_i showed opposite trends with the increase of fertilization amount. Yield was significant positively correlated with chlorophyll a， chlorophyll b， F_v /F_m （P<0.01）， extremely significant negatively correlated with NPQ （P<0.01）， significantly positively correlated with T_r （P<0.05）， but there was no significant correlation with carotenoid content， ΦPSⅡ， qP， P_n， G_s and C_i（P>0.05）. Nitrogen fertilizers could increase yield by increasing chlorophyll content， enhancing F_v /F_m， reducing NPQ， and improving photosynthetic performance， so as to achieve the purpose of increasing production.

Key words: forage oats, nitrogen fertilizer, yield, fluorescence parameters, photosynthetic characteristics

摘要：

为探讨不同饲用燕麦品种产量、叶绿素含量、荧光特性及光合特性对施氮量的响应情况，以科尔沁沙地适宜种植的饲用燕麦品种为材料，研究了氮肥对饲用燕麦产量和光合生理特性的影响。采用随机区组试验设计，在科尔沁沙地种植燕王、牧王、甜燕1号和牧乐思4个主栽饲用燕麦品种，分别于燕麦分蘖期、拔节期、抽穗期、开花期按照15%、40%、25%、20%比例追施0（N0，CK）、100（N100）、200（N200）、300 kg·hm^-2（N300）氮肥（纯N），灌浆期测定叶绿素含量、类胡萝卜素含量、荧光参数指标及光合指标，成熟期测定产量。结果表明，燕王和牧王在N200施氮水平下产量最高，为低氮高效型饲用燕麦品种；甜燕1号和牧乐思在N300施氮水平下产量最高，为高氮高效型饲用燕麦品种。随着施氮水平的提高，不同饲用燕麦品种叶绿素含量、潜在光化学效率（potential photochemical efficiency，F_v /F_m）、实际光化学效率（actual photo-chemical efficiency，ΦPSⅡ）、光化学猝灭系数（photochemical quenching coefficient，qP）、净光合速率（net photosynthetic rate，P_n）、气孔导度（stomatal conductance，G_s）、蒸腾速率（transpiration rate，T_r）呈现先增加后降低或增加的变化趋势，而非光化学猝灭系数（non-photochemical quenching coefficient，NPQ）和胞间CO₂浓度（intercellular CO₂ concentration，C_i）随着施肥量的增加却出现相反的趋势。产量与叶绿素a、叶绿素b、F_v /F_m呈极显著正相关（P<0.01），与NPQ呈极显著负相关（P<0.01），与T_r呈显著正相关（P<0.05），但与类胡萝卜素含量、ΦPSⅡ、qP、P_n、G_s、C_i无显著相关性（P>0.05）。氮肥主要通过提高叶绿素含量，增强F_v /F_m，降低NPQ，提高光合性能，进而达到增产的目的。

关键词: 饲用燕麦, 氮肥, 产量, 荧光参数, 光合特性