不同施肥方式对巨柏苗木生长及光合作用的影响

Effects of different fertilization methods on growth and photosynthesis of Cupressus gigantea seedlings

以巨柏(Cupressus gigantea)2年生播种苗为材料,研究指数施肥(EF)、2倍指数施肥(DEF)、平均施肥(CF)对巨柏苗生长及光合作用的影响.结果表明:施肥后巨柏苗苗高、地径、生物量、新生根总根长、表面积、体积均明显高于不施肥对照(CK).不同施肥方式下巨柏苗的苗高、地径、生物量等均在EF时显著高于CF和DEF时,其中EF时地上、地下鲜质量和地上、地下干质量分别较CK时增加了592.34%,71.10%,461.39%和168.89%.EF时新生根长度最大,为1464.78 cm,较CK时增加了68.20%,CF和DEF时新生根总根长较CK时分别增加了34.45%和15.47%.CK、CF和DEF时净光合速率日变化均在10:00出现第一个峰值,14:00出现最大峰值;EF时净光合速率日变化峰值出现在14:00,且显著高于其他3组处理.巨柏苗的日均净光合速率和水分利用效率在EF和DEF时显著高于CF和CK时.巨柏苗在不同施肥条件下的光响应曲线差异明显,EF时苗木的光补偿点最小,约为CK时的63.37%,表观量子效率在EF时最大,CK时最小,可见EF可增强巨柏苗对弱光的利用;但各处理下光饱和点差异不大,均在1400μmol/(m^(2)·s)左右时达到饱和.综上,采用EF能有效促进巨柏苗生长、生根及光合作用能力,各方面表现最佳.

The effects of exponential fertilization(EF),double exponential fertilization(DEF)and mean fertilization(CF),respectively on the growth and photosynthesis of two-year-old Cupressus gigantea seedlings were studied.The results suggested that after fertilization,the seedling height,ground diameter,biomass,total root length,surface area and volume of new roots were significantly higher than those of the control ones without fertilization(CK).The seedling height,ground diameter and biomass of C.gigantea with EF were significantly higher than those with CF and DEF.Compared with CK,the aboveground and underground fress mass,the aboveground and underground dry mass with EF were increased by 592.34%,71.10%,461.39%and 168.89%,respectively.The maximum total length of new roots was 1464.78 cm with EF,which was longer than that with CK by 68.20%,and the total length of new roots increased by 34.45%and 15.47%,respectively with CF and DEF compared with CK.The first peak value of net photosynthetic rates appeared at 10:00 for CK,CF and DEF,and the maximum value appeared at 14:00.The peak value of net photosynthetic rates for those with EF appeared at 14:00,which was significantly higher than those with the other three treatments.The average daily net photosynthetic rate and water use efficiency of C.gigantea seedlings with EF and DEF were significantly higher than those with CF and CK.The light response curves at different fertilization treatments showed obvious differences.The light compensation point of seedlings with EF was the smallest,which was about 63.37%of that with CK.The apparent quantum efficiency was the largest with EF and the smallest with CK.Thus,EF can enhance the utilization of weak light.However,there was no significant difference in the light saturation point among the different treatments,about 1400μmol/(m^(2)·s).As a conclusion,EF can effectively promote the growth,rooting and photosynthetic capacity of C.gigantea seedlings,with best performance.