乙烯利对降香黄檀生长和光合生理特性的影响

【目的】探究不同浓度乙烯利对降香黄檀生长、光合生理特性的影响,为后期心材形成提供参考。【方法】以胸径6~8 cm的降香黄檀为研究对象,设置CK、E0.1%(乙烯利质量分数0.1%,后同)、E0.5%、E2.5% 4个乙烯利处理,研究各处理对降香黄檀生长指标增长量、叶绿素含量(SPAD值)、比叶面积(SLA)、水分利用效率(WUE)和光合参数的影响。【结果】在3个乙烯利处理中,E0.1%、E0.5%处理胸径增长量(ΔD)均高于对照,分别增加了8.97%、6.07%;E2.5%处理的树高增长量(ΔH)和材积增长量(ΔV)均较对照低,分别减少了67.39%和59.33%。各乙烯利处理对降香黄檀叶绿素含量(SPAD值)有显著影响,大小顺序为E0.1%>E0.5%>CK>E2.5%。E0.1%、E0.5%处理叶干质量、叶面积显著高于E2.5%处理,各处理比叶面积(SLA)大小顺序为E0.1%>E0.5%>CK>E2.5%。Pearson相关分析表明,E0.1%、E0.5%、E2.5%处理下SLA和WUE都具有显著负相关关系。光响应曲线所得光合参数显示,最大净光合速率(P_n,max)随乙烯利浓度的增加先升高后下降,E0.1%、E0.5%处理分别较CK增加了38%、26.22%。光饱和点(P_Lsp)随注射乙烯利的浓度先增加后略微降低但均高于对照,E0.5%处理最高。乙烯利各处理光补偿点(P_Lcp)均低于对照,E0.1%、E0.5%处理比CK降低了16.37%、20.92%。【结论】低浓度乙烯利可提高降香黄檀的叶绿素含量、比叶面积、净光合速率等光合特征参数,E2.5%的乙烯利不利于降香黄檀树高和材积的增长。

Effects of ethephon on the growth and photosynthetic characteristics of Dalbergia odorifera

【Objective】In this study,we documented the growth as well as photosynthetic and physiological characteristics of Dalbergia odorifera after injecting various concentrations of ethephon(ETH)with the aim of collecting data to provide a theoretical basis for efficient cultivation and later heartwood formation.【Method】Dalbergia odorifera with a DBH of 6-8 cm was taken as the research object and divided into 4 treatments groups,E0.1%,E0.5%,E2.5%and control group(CK).The effect of different treatments on the growth indicators of D.odorifera,namely,growth indicator increment,SPAD value,specific leaf area(SLA),water use efficiency(WUE)and photosynthetic parameters was studied.【Result】Among the 3 ethephon treatments,the DBH increase(ΔD)with E0.1% and E0.5%treatments was larger than that of CK by 8.97%and 6.07%,respectively.Both the increase in tree height(ΔH)and the volume of the individual tree(ΔV)with E2.5%treatment were lower compared to CK with a decrease of 67.39%and 59.33%,respectively.Ethephon had a significant effect on the SPAD value of D.odorifera,and the order was E0.1%>E0.5%>CK>E2.5%.The leaf dry weight and leaf area were significantly higher at E0.1%and E0.5%compared to E2.5%.The order of SLA was E0.1%>E0.5%>CK>E2.5%.According to the Pearson correlation analysis,all ETH treatments had a significant negative effect on both SLA and WUE.The photosynthetic parameters obtained from the light response curve showed that the maximum net photosynthetic rate(Pn,max),initially increased,and then decreased with increasing concentration of ETH.The rate for E0.1%and E0.5%was higher than that for CK by 38.00%and 26.22%,respectively.The light saturation point(PLsp),initially increased,and then slightly decreased with increasing concentration of ETH injected.The values for all the treatments were higher than that for CK while those it was the highest for E0.5%.The light compensation points(PLcp)for all ETH-treated groups were lower than that for CK,and those for E0.1%and E0.5%were significantly lower than that for CK by 16.37%and 20.92%.【Conclusion】Low concentration of ETH could facilitate the chlorophyll content of D.odorifera,SLA,Pn and other photosynthetic characteristics;at a high concentration of 2.5%,ETH was counterproductive to the height and individual tree volume increase of D.odorifera.