施肥对喜马拉雅红豆杉生理指标及化学计量特征的影响

Effects of fertilization on physiology indexes and stoichiometric characteristics of Taxus himalayana

【目的】为探究不同施肥量对喜马拉雅红豆杉幼苗生理指标和养分含量的影响,筛选适宜红豆杉生长发育的最佳施肥量。【方法】设计不同浓度N、PO、KO施肥量(CK、F1、F2、F3和F4)处理,测定喜马拉雅红豆杉叶片、茎干和根系的生理指标及有机碳(OC)、全氮(TN)、全磷(TP)和全钾(TK)含量。【结果】(1)随着施肥量的增加,红豆杉叶片Chla及Chlb含量逐渐增加,在F3时达到最大值,类胡萝卜素含量表现为:F1>F2>F3>F4>CK。可溶性糖和可溶性蛋白含量最大值出现在F3处理,其值分别为15.80 mmol/L和1.22 mg/g,显著高于CK和F1处理(P<0.05)。丙二醛含量随着施肥量的增加呈逐渐增加的趋势,到F4处理时,其值达到了1.38μmol/L。可见,在本研究范围内,F3处理更有利于喜马拉雅红豆杉营养物质的累积。(2)随施肥量的增加,OC、TN、TP含量在根、茎、叶中均呈增加的趋势,TK含量仅在根系中呈增加的趋势,在茎、叶中呈先增加后降低的趋势;同一施肥水平,喜马拉雅红豆杉茎的OC含量大于叶和根,叶的TN、TP、TK含量均高于茎和根。可见,喜马拉雅红豆杉茎的碳累积能力大于叶和根,而叶片的氮、磷、钾累积能力大于茎和根。(3)随着施肥量的增加,根系C∶N呈增加的趋势,其中F4较CK高出了13.53%,茎、叶器官呈先降低后增加的趋势;根、茎、叶器官的C∶P分别介于166.01~323.68、311.33~328.79和183.69~252.33,N∶P分别介于2.50~5.39、4.15~6.08和7.42~8.44。鉴于此,在后期的施肥试验中应加大氮肥的投入。【结论】施肥可显著提高喜马拉雅红豆杉根、茎、叶三大器官的氮、磷、钾含量,但是随着施肥量的增加,喜马拉雅红豆杉光合生理指标及营养物质呈先增加后降低的趋势。在本研究施肥配比范围内,N、P_(2)O_(5)、K_(2)O分别为2.40、1.80和1.80 g时红豆杉生长较好。

【Objective】The present paper aimed to explore the effects of different fertilization rates on physiological indexes and nutrient content of Taxus himalayana seedlings, and to screen the best fertilization rate for the growth and development of T.himalayana.【Method】The effects of N, POand KO(CK,F1,F2,F3 and F4) on the growth of T.himalayana were studied.The physiological indexes of leaves, stems and roots, and the contents of organic carbon(OC), total nitrogen(TN), total phosphorus(TP) and total potassium(TK) were determined.【Result】(i) With the increase of fertilizer application, Chla and chlb contents in leaves of T.himalayana increased gradually and reached the maximum value at F3.The carotenoid content was as follows: F1 > F2 > F3 > F4 > CK.The maximum contents of soluble sugar and soluble protein were 15.80 mmol/L and 1.22 mg/g in F3 treatment, which were significantly higher than those in CK and F1 treatment(P<0.05).Malondialdehyde content increased gradually with the increase of fertilizer application, and reached 1.38 μmol/L in F4 treatment.Therefore, in the scope of this study, F3 treatment was more conducive to the accumulation of nutrients in T.himalayana.(ii) The contents of OC, TN and TP in roots, stems and leaves increased with the increase of fertilizer application, while the contents of TK only increased in roots, and first increased and then decreased in stems and leaves;At the same fertilization level, the content of OC in stem was higher than that in leaf and root, and the content of TN, TP and TK in leaf was higher than that in stem and root.(iii) With the increase of fertilizer application, the C∶N ratio of root system increased, and F4 was 13.53% higher than CK;The C∶P ratio of root, stem and leaf were 166.01-323.68, 311.33-328.79 and 183.69-252.33, respectively, and the N∶P ratio were 2.50-5.39, 4.15-6.08 and 7.42-8.44, respectively.In view of this, the input of nitrogen fertilizer should be increased in the later fertilization experiment.【Conclusion】Fertilization could significantly increase the contents of N, P and K in root, stem and leaf of T.himalayana, but with the increase of fertilization, photosynthetic physiological indexes and nutrients of T.himalayana increased first and then decreased.In the range of fertilization ratio in this study, when N, P_(2)O_(5) and K_(2)O were 2.40 g, 1.80 g and 1.80 g respectively, Taxus grew better.