| Osmanthus fragrans Lour.var.aurantiacus is one of ten famous Chinese traditional flowers.Because of its graceful,evergreen,floral rich,Osmanthus fragrans Lour.var.aurantiacus is in a wide range of applications in traditional Chinese gardens.Due to its rich osmanthus alcohol,pork and beans natural compounds such as acids,lauric acid,Osmanthus fragrans Lour.var.aurantiacus also has a high economic value in medicine and food industry.Pucheng is famous for Osmanthus fragrans Lour.var.aurantiacus seedlings,whose industry plays an important role in the county’s rural economy,but artificial cultivation of seedlings grow slowly,and a long time to growth has limited its development.In order to promote the formation of biomass of seedlings,shorten the rearing period,to promote development of Osmanthus fragrans Lour.var.aurantiacus industry.It is important to understand the effect of fertilizing on physiological and ecological characters of Osmanthus fragrans Lour.var.aurantiacus seedlings.The two-year-old Osmanthus fragrans ’Pucheng dangui’ seedings were treated with fertilizer combinations of Nitrogen(N),Phosphorus(P)and potassium(K)at three different levels,[N0(0 g·strain-1),Ni(5 g·strain-1),N2(10 g-strain-1);P0(0 g·strain-1),P1(2 g·strain-1),P2(4 g·strain-1);K0(0 g·strain-1),K1(3 g·strain-1),K2(6 g·strain-1)],in the randomized block design under field condition and laboratory analysis to investigate the effects of fertilization on physiological and ecological characteristics of Osmanthus fragrans Lour.var.aurantiacus seedlings.The results showed:(1)A different effect of seedling height,ground diameter,total biomass under N,P,K ratio,the seedling height and ground diameter of the N10P2K0 treatment had a higest increase volume and the most biomass was the N10P4K3 treatment.N,P,K ratio can affect the biomass distribution of roots,stem and leaves,the biomass of stem significantly higher than that of root and leaves(p<0.05).N,P,K ratio treatments improved the total biomass dramatically,and the biomass of root,stem,leaves and whole plant of the N10P4K3 treatment was much more than others markedly.At the same time,a higher content of LA,SLA(p<0.05),but a lower content of LMA(p<0.05)compared to the CK treatment.(2)N,P,K ratio treatments had a great effect on the content of Chlorophyll a(Chl a),Chlorophyll b(Chl b),Chlorophyll a/b(Chl a/b)(p<0.01),different level promoted the content of Chl a and Chl b,but the ratio of Chl a/b decreased,which shows that fertilization promotes the synthesis of Chlorophyll,but also increases the capture of light energy,and improve its photosynthetic ability.(3)N,P,K ratio treatments had a different effect on Fluorescence parameters of seedings.Initial Fluorescence(F0)and Maximal fluorescence(Fm)had a total trend of decreased firstly and then increased,but the N10P4K3 treatment increased firstly and then decreased.And the N10P2K0 treatment’s PS Ⅱ potential efficiency(Fv/F0)and PS Ⅱ Maximal photochemical efficiency(Fv/Fm)higher relatively,N10P0K6 to N10P4K3 treatment applied much more nitrogen fertilizer,their Fv/F0 and Fv/Fm was relatively improved,which help improved the CO2 assimilation rate,improve the photosynthetic capacity and accumulated organic matter.(4)N,P,K ratio treatments had a different effect on soluble proteins(SP)and superoxide dismutase(SOD)and peroxidase(POD).Although no significant correlation of the three,the SOD and POD activity and the contents of SP has the similar trends:reduced firstly and then increased gradually,different supply of N,P,K had a very significant impact on SOD and PDO(p<0.01).SP content’s maximum occurred in October,significantly improved the content of SP compared with CK treatment(p<0.05).SOD activity’s maximum also occurred in October,N0P2K3,N0P4K6,N10P4K3 treatment in October increased by 11.88%,10.44%,9.29%compared to CK treatment(p<0.05).POD activity in different months was significantly different,all maximum values appear in August except the N10P4K3 treatment.(5)N,P,K ratio treatments improved the content of Cmass,Nmass,Pmass remarkedly,with no clear trend of Kmass,but K increased firstly and then decreased over 8-12 months.Cmass,Nmass,Pmass and Kmas had some fluctuations along with months,but C:N,C:P,N:P in Decemberwas much stable than that in August.The highest N recovery efficiency is N5P4K0 treatment,up to 38.8%,the highest P recovery efficiency was N10P2K0 treatment,up to 19.1%,and the highest K recovery efficiency was N5P2K6 treatment,up to 9.0%,and the highest N,P,K total efficiency was N10P4K3 treatment.There was a significant allometric relationship between leaf Nmess and Cmass,Pmass and Cmass,but not Nmass and P mass.(6)N,P,K ratio treatments had a great significant impact on endogenous hormones in Osmanthus fragrans ’Puchengdan ’.The content of indole-3-acetic acid(IAA),GAs,abscisic(ABA),ZR decreased in all different fertilization,then gradually increased.So different levels of fertilizer had different works.The content of IAA and ZR of N5P0K3 treatment had the highest value,and largest increasement.And correlation analysis showed that IAA,ABA,and ZR had a highly significant positive correlation(p<0.01),and ABA was positively correlated with the ZR(p<0.05).These results showed that Osmanthus fragrans var.aurantiacus.seeldings with N,P,K fertilizer combined application had a great adjustment of indicator of photosynthetic pigment contents,fluorescence parameters,protective enzyme activity and endogenous hormones,and proper ratio can improve the capacity of photosynthesis and stress resistance,indirectly contributed to the increasement of biomass and shortened tending.The optimum ratio of N,P,K for seedlings was N10P4K3 treatment(N:10 g·strain-1,P:4 g·strain-1,K:3 g·strain-1).It had the highest N,P,K total efficiency,with the biomass maximum,which is 2.06 times as the CK treatment(p<0.01).The content of chlorophyll was higher than the CK treatment on June-August and cumulative advantage of SP can be sustained to highest value(8.37 ± 0.49)mg·g-1 which is 3.35 times as CK treatment(p<0.01)by October in the growing season.SOD and POD in August-September had a significant influence than that in March-June.This suggested a higher photosynthetic pigment contents and protective enzyme activity of seeldings.The leaf LA,Cmass,Nmass,N:P was up to the highest value indicating that there were no significant relationship between N10P4K3 and N5P4K0,N0P4K6 treatment on SLA,which lower than N10P2K0 treatment,but N:P<10.So the seedings were in need of further more N to accelerate their rapid growth.This investigation can provide a useful information for high yield production of Osmanthus fragrans var.aurantiacus.,also is of theoretical and practical significance for proper fertilization of Osmanthus fragrans var.aurantiacus. |
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