5个观赏海棠品种光合特性的研究

【目的】探究观赏海棠光合生理特性与生长之间的关系,为有效引种和培育不同需光特性的观赏海棠新品种提供理论依据。【方法】以5个生长速度不同的观赏海棠品种(‘薄荷糖'、‘百夫长'、‘玛丽波特'、‘长虹'和‘丽莎')1年生嫁接苗为试材,对其生长指标及其光合日变化规律和光响应曲线进行测定。【结果】①生长速度的快慢与最大净光合速率(P_n,max)的大小呈显著正相关,生长越快,P_n,max越大; 5个品种P_n,max大小顺序依次为:‘丽莎'>‘长虹'>‘玛丽波特'净光合速率>‘百夫长'>‘薄荷糖'。②‘玛丽波特'净光合速率日变化规律呈双峰型,这种“光合午休”现象是由气孔限制因素所引起,而其他4个品种的日变化均呈单峰型。③各海棠品种光补偿点(P_LCP)均大于20 μmol/(m²·s),表现为阳性植物特征,但其需光性不同,P_LCP的范围为27～67 μmol/(m²·s),光饱和点P_LSP的范围为574～976 μmol/(m²·s)。其中‘丽莎'为低P_LCP高P_LSP类型,属于对光环境适应性强的品种,表现出较高的生长量,可栽植的地区比较广泛。‘薄荷糖'为高P_LCP低P_LSP的类型,属于对光环境适应性较窄的品种,表现出较低的生长量,可栽植地区的范围比较窄。【结论】5个观赏海棠品种的生长量指标和最大净光合速率(P_n,max)之间呈显著正相关,因此,笔者认为,可以将P_n,max作为早期估测观赏海棠生长量的参考指标之一,以指导观赏海棠的良种推广应用、生产实践及新品种选育等。

Study on photosynthetic characteristics of five ornamental crabapple

Objective] The present study investigated the relationship between the photosynthetic physiology and growth of ornamental crabapples,in order to provide a theoretical basis for effectively introducing and cultivating new varieties of ornamental crabapple with different ligbt-demand characteristics.Method] The diurnal variation law of photosynthesis and light response curve of 1-year-old specimens from five ornamental crabapple cultivars with various growth speeds (Malus ‘ Candymint',‘ Centurion',‘ Rainbow',‘ Mary Potter',and ‘ Lisa') were measured.Results] ①Growth rate was significantly positively correlated with the maximum net photosynthetic rate (P),with both growth rate and P increasing as follows:‘ Lisa'＞ ‘ Rainbow'＞ ‘ Mary Potter'＞‘ Centurion'＞ ‘ Candymint'.()Meanwhile,the diurnal variation of ‘Mary Potter'was “bimodal” (i.e.,“midday depression”),which was caused by stomatal limitation,whereas the diurnal variation of the other four varieties was “single peak”.③The light compensation points (PLCP)of different crabapple varieties were higher than 20 μmol/(m2·s),which showed positive plant characteristics.However,theirs light requirement were different,PLCP range was 27-67 μ mol/(m2 ·s),and light saturation point (PLSP) ranged fiom 574 to 976 μmol/(m2 ·s).Among the five cultivars,‘Lisa'possessed a low PLCPand high PLsP,indicating strong adaptability to light conditions,a high growth rate,and the ability to reach a wide range of areas,and ‘Candymint'possessed a high PLCP and low PLSP,indicating relatively weak adaptability to light conditions,a low growth rate,and a narrow range of cultivable areas.Conclusion] There was a significant positive correlation between the growth index and maximum net photosynthetic rate (P) of the five ornamental crabapple cultivars.We suggest that P can be used as an indicator of the early growth of ornamental crabapples,and to guide the application of breeding varieties of crabapple,production practices and new varieties of breeding.