硼利用效率不同的柑橘砧木光合性能差异研究

【目的】 通过研究枳橙砧木 (硼不敏感型) 和枳壳砧木 (硼敏感型) 对不同硼浓度处理的反应，重点揭示两种柑橘砧木硼利用效率、光合性能及产物的差异。 【方法】 采用营养液培养的方法，设置 B0 (B0)、2 (B2)、5 (B5)、10 (B10) 和 50 μmol/L (B50) 5 个硼浓度对枳橙和枳壳砧木进行培养，通过测定植株硼含量，叶片中不同形态硼、色素含量，光合速率及糖类物质含量，探讨不同砧木硼利用效率及光合性能的差异。 【结果】 在相同硼浓度条件下，枳橙砧木植株的硼利用效率均大于枳壳砧木，不施硼时，枳橙的硼利用效率较枳壳砧木高 38.6%；两种砧木半束缚态硼/自由态硼的比值 (R) ，在各个硼处理中，枳壳砧木的 R 值均低于枳橙砧木，即枳橙砧木在细胞水平上的硼利用能力大于枳壳砧木；缺硼会降低枳壳和枳橙砧木叶绿素 a (Chl a)、叶绿素 b (Chl b) 和类胡萝卜素 (Car) 等光合色素的含量，其中枳壳砧木受缺硼影响较大，且不施硼显著降低了这两种砧木的净光合速率，相同硼水平条件下，枳橙砧木的净光合速率显著高于枳壳砧木 (B10 除外) ；两种砧木叶片可溶性糖、果糖和淀粉含量在 B0 时均高于其他处理，B0、B2 及 B5 处理，枳壳砧木叶片可溶性糖、蔗糖、果糖均显著高于枳橙砧木。 【结论】 枳橙砧木在植株水平和细胞水平的硼效率均高于枳壳砧木，光合特性和光合产物积累的不同或许是两者硼效率差异的一个关键因子。

Leaf photosynthetic characteristics of citrus rootstocks with different boron efficiency

Objectives] This paper showed the study of the difference in photosynthetic characteristics between citrange boron (B)-insensitivity] and trifoliate orange (B-sensitivity) seedlings.Methods] Hydroponic experiments were conducted with 5 B levels,including 0 (B0)、2 (B2)、5 (B5)、10 (B10) and 50 μmol/L (B50).The difference of B-efficiency and photosynthesis between the two rootstocks was analyzed according to the concentration of B forms,photosynthetic pigment,net photosynthetic rate and carbohydrate.Results] The B effective utilization rate of citrange sample was higher than trifoliate orange sample under the same treatment,especially in the treatment of B0.The citrange used 38.6％ more B compared with trifoliate orange.Under the different B treatments,R value (R=semi-bound B/free B) was much lower in trifoliate orange samples than citrange samples,which indicated B utilization of citrange at the cellular level was significantly higher than trifoliate orange.B deficiency reduced photosynthetic pigment content (Chl a,Chl b,Car) of two rootstocks leaves,and there were much more significant effects of B deficiency on trifoliate orange.B deficiency significantly reduced the net photosynthetic rate in both two rootstocks.The net photosynthetic rate was significantly higher in citrange than trifoliate under the condition of B-deficiency (B0,B2,B5) and rich B (B50).There was a higher content of soluble sugars,fructose,and starch in B0 treated samples compared with other treatments.Under B-deficiency treatment,moreover,a higher level of soluble sugars,sucrose,and fructose was observed in trifoliate orange than that in citrange.Conclusions] Citrange showed more effective B utilization than trifoliate orange.The differences of photosynthetic characteristics and accumulation of photosynthetic products could be one of the key factors leading to the different B-efficiency of two rootstocks.