不同种源桤木嫁接幼苗的生长及光合特性

Growth and Photosynthetic Characteristics of Grafted Alnus Seedlings from Different Provenances

【目的】研究不同种源桤木嫁接幼苗的生长及光合特性,为桤木良种育苗提供基础理论依据。【方法】采集平昌、宣汉、恩阳、金堂4个种源桤木穗条,选取长势基本一致的实生桤木幼苗为砧木,于2015年1月进行嫁接,同年7月测定嫁接苗苗高、基径、叶绿素含量、光合生理等指标。【结果】金堂嫁接幼苗的苗高和基径最大,显著高于其余种源(P<0.05);恩阳嫁接幼苗的叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量最高,分别为2.45、0.61、3.06和0.64 mg/g,与金堂嫁接幼苗差异不显著(P>0.05),与平昌的差异显著(P<0.05);恩阳和金堂嫁接幼苗的最大光合速率(P_(n max))和表观量子效率(AQY)较高,且差异不显著(P>0.05),金堂嫁接幼苗的暗呼吸速率(R_d)较慢,与恩阳差异显著(P<0.05);桤木嫁接幼苗的光合速率(P_n)与气孔导度(G_s)和蒸腾速率(T_r)极显著(P<0.01)相关。【结论】4个种源桤木嫁接幼苗生长及光合特性差异明显,恩阳和金堂种源桤木嫁接幼苗光合色素含量较高,光合能力较强,生长速度较快,具有较好的培育前景。

【Objective】The aim of the study was to investigate the growth and photosynthetic characteristics of grafted alnus seedlings from different provenances and to provide a theoretical reference for the establishment of alder seed orchard.【Method】Four different alnus provenances were saompled from Pingchang,Xuanhan,Jintang and Enyang. The branches were grafted on the basically consistent seedling of alder in January 2015. After 6 months,the seedling height,basal diameter,chlorophyll content and photosynthetic parameters were determined.【Results】The seedling height and basal diameter of the seedling from Jintang war largest among 4 grafted seedlings(P<0.05). The content of chlorophyll a,chlorophyll b,total chlorophyll and carotenoid was 2.45 mg/g,0.61 mg/g,3.06 mg/g and 0.64 mg/g,respectively. The grafted seedling of Enyang was similar with the performance of Jintang,but were different from Pingchang and Xuanhan( P<0.05). The maximum net photosynthetic rate(P_(n max)) and apparent quantum yield(AQY) of the grafted seedling of Enyang was similar with those of Jintang,but were significantly different from those of Pingchang and Xuanhan( P<0.05). However,the grafted seedling of Jintang exhibited lowest dark respiration rate(R_d),which was significantly lower( P<0.05) than the perfermance of Enyang. The photosynthetic rate( P_n) of alder grafted seedlings was significantly correlated( P<0.01) with stomatal conductance(G_s) and transpiration rate(T_r). Therefore,under certain conditions,the level of photosynthesis could be affected by the level of gas exchange parameters.【Conclusion】As discussed above,there were significant differences in growth and photosynthetic properties among 4 different provenances.Among them,grafted alnus seedlings from Enyang and Jintang,with faster growth rate,higher photosynthetic pigment and stronger photosynthetic ability,are more sutitable for breed.