余紅梅，李廷軒，張錫洲，鄭子成，余海英

(四川農(nóng)業(yè)大學(xué)資源學(xué)院，四川 成都 611130)

施氮量對(duì)礦山生態(tài)型粗齒冷水花磷富集特性的影響

余紅梅，李廷軒*，張錫洲，鄭子成，余海英

(四川農(nóng)業(yè)大學(xué)資源學(xué)院，四川 成都 611130)

摘要：采用土培試驗(yàn)，以礦山生態(tài)型粗齒冷水花為研究對(duì)象，非礦山生態(tài)型為對(duì)照，探討了高磷(400 mg P/kg)處理下不同施氮量(0，70，140，210，280和350 mg N/kg)對(duì)礦山生態(tài)型粗齒冷水花磷富集特性的影響，為利用礦山生態(tài)型粗齒冷水花提取土壤中過(guò)量的磷，防治磷的非點(diǎn)源污染提供理論依據(jù)。結(jié)果表明,1)礦山生態(tài)型粗齒冷水花地上部和地下部的生物量、磷積累量均在140 mg/kg施氮量下達(dá)最大值；其中，礦山生態(tài)型地上部磷積累量為223.73 mg/株，非礦山生態(tài)型為159.79 mg/株。不同施氮量處理下，礦山生態(tài)型地上部生物量和磷積累量顯著高于非礦山生態(tài)型。粗齒冷水花磷富集系數(shù)隨施氮量增加逐漸升高，遷移率均高于50%，達(dá)到71%~88%。2)隨施氮量增加，礦山生態(tài)型根系酸性磷酸酶活性逐漸升高，而植酸酶活性先升高后降低，在140 mg/kg達(dá)最大值。各施氮量下的礦山生態(tài)型根系酸性磷酸酶和植酸酶活性均顯著高于非礦山生態(tài)型，分別為非礦山生態(tài)型的1.22~1.67倍和1.02~1.07倍。在70~210 mg/kg范圍施氮有助于促進(jìn)礦山生態(tài)型粗齒冷水花生長(zhǎng)，增加植株對(duì)磷的積累，提高其富磷潛力。本研究條件下，140 mg/kg為最佳施氮量。

關(guān)鍵詞：施氮量；磷富集；粗齒冷水花；生態(tài)型；植物修復(fù)

DOI：10.11686/cyxb2015023http://cyxb.lzu.edu.cn

余紅梅，李廷軒，張錫洲，鄭子成，余海英. 施氮量對(duì)礦山生態(tài)型粗齒冷水花磷富集特性的影響. 草業(yè)學(xué)報(bào), 2015, 24(8): 85-92.

Yu H M, Li T X, Zhang X Z, Zheng Z C, Yu H Y. Effect of different levels of N supply on P accumulation characteristics of a ‘mining ecotype’ ofPileasinofasciata. Acta Prataculturae Sinica, 2015, 24(8): 85-92.

收稿日期：2015-01-16；改回日期：2015-03-30

基金項(xiàng)目：國(guó)家自然科學(xué)基金項(xiàng)目(31401377)，四川省教育廳重點(diǎn)項(xiàng)目(14ZA0002)，四川省科技支撐項(xiàng)目(2013NZ0044)和四川省科技支撐計(jì)劃(2013NZ0029)資助。

作者簡(jiǎn)介：余紅梅(1989-)，女，貴州遵義人，在讀碩士。E-mail:18200353350@163.com

通訊作者*Corresponding author. E-mail:litinx@263.net

Effect of different levels of N supply on P accumulation characteristics of a ‘mining ecotype’ ofPileasinofasciata

YU Hong-Mei, LI Ting-Xuan*, ZHANG Xi-Zhou, ZHENG Zi-Cheng, YU Hai-Ying

CollegeofResources,SichuanAgriculturalUniversity,Chengdu611130,China

Abstract:Quantities of P fertilizer and organic fertilizer are supplied in agro-ecosystems to improve the soil available P content and maintain soil fertility, but ultimately resulting in P immobilization and accumulation in the soil. Phytoextraction is a practical method for recovering the excess P after soils have become enriched. In order to provide a theoretical basis for extracting excess P from soil to assist with prevention and control of non-point source pollution, it was necessary to determine the P accumulation characteristics of a ‘mining ecotype’ (ME) of Pilea sinofasciata. This material had previously been screened as showing promise for P extraction from enriched soil. The effects of different levels of nitrogen (N) supply (0, 70, 140, 210, 280, 350 mg N/kg) on plant growth and P accumulation characteristics in the ME of P. sinofasciata were analyzed，with a non-mining ecotype (NME) as contrast. All treatments had the same P supply (400 mg P/kg soil). Pot experiments were carried out in a greenhouse at Sichuan Agricultural University, Sichuan province, China in 2013. Key results were: 1)For both shoot and root biomass, P accumulation of P. sinofasciata significantly increased with increased N supply up to 140 mg/kg, and then decreased with additional N supply. Shoot P accumulation of the ME was maximized at 140 mg/kg N supply, and ME demonstrated greater shoot P accumulation (223.73 mg/plant) than the NME (159.79 mg/plant) under different rates of N supply. The bioaccumulation coefficient of the ME was more than 1, while translation rate was more than 50%, and as high as 71%-88%. 2) The activities of acid phosphatase and phytase in P. sinofasciata peaked at N application rates of 350 mg/kg and 140 mg/kg, respectively, and the activities of these two enzymes in the ME were markedly higher (P<0.05) than those in the NME, being increased by a factor of 1.22-1.67, and 1.02-1.07, respectively. In conclusion, the P. sinofasciata ME showed substantial P accumulation ability under N application rates of 70-210 mg/kg. Thus, P. sinofasciata is a good candidate species for P phytoextraction, with the best results obtained when N was added at 140 mg/kg soil.

Key words:nitrogen (N) supply; phosphorus enrichment; Pilea sinofasciata; ecotype; phytoremediation

在農(nóng)業(yè)生產(chǎn)中，過(guò)量施用含磷肥料以及畜禽糞便任意排放等易造成土壤磷過(guò)剩，加劇水體富營(yíng)養(yǎng)化等環(huán)境問(wèn)題[1-5]。因此，尋找合適的方法減少土壤環(huán)境中過(guò)量磷已受到廣泛關(guān)注。植物提取能通過(guò)植物收獲等方式帶走磷，是一種較為有效的治理措施[6-8]。相關(guān)研究指出，Marshall和Gulf黑麥草[9-10]、Duo grass[11-12]、黃瓜(Cucumissativus)和黃南瓜(Cucurbitapepovar.melopepo)[13]等均能用于磷過(guò)剩環(huán)境修復(fù)，其地上部磷含量高達(dá)10 g/kg以上，然而這些富磷植物多數(shù)為一年生植物，且存在生物量小、磷積累量低、對(duì)環(huán)境適應(yīng)力較弱等不足，導(dǎo)致磷提取效果不佳。因此，提高富磷植物磷富集潛力已成為當(dāng)下研究的熱點(diǎn)。采用多次收獲和暖冷季混種等方式可在一定程度上提高牧草磷富集潛力[14-15]，但其應(yīng)用范圍有限，效果不甚理想。Zheng等[16]研究表明，礦山生態(tài)型水蓼(Polygonumhydropiper)對(duì)畜禽廢水中氮、磷去除率隨培養(yǎng)時(shí)間延長(zhǎng)均升高；據(jù)Silveira等[17]報(bào)道，百喜草(Paspalumnotatum)和象草(Pennisetumpurpureum)等多年生牧草種植在富磷土壤后植株體內(nèi)氮磷含量均較高；表明植物對(duì)氮、磷的吸收存在協(xié)同性，適宜施氮可改善植物對(duì)土壤磷的吸收積累。Newman等[14]研究表明，適宜施氮可提高多年生暖季牧草百喜草和扁穗牛鞭草(Hemarthriaaltissima)的產(chǎn)量和磷去除率；適宜施氮亦可促進(jìn)多年生黑麥草(Loliummultiflorum)和狗牙根(Cynodondactylon)吸收土壤中的磷以提高植株生物量和磷含量，從而有效降低表層土壤磷含量[15]；表明增施氮肥有利于植物提取土壤中的磷。Xiao等[18-19]調(diào)查發(fā)現(xiàn)，粗齒冷水花(Pileasinofasciata)是一種多年生草本植物，具有地上部生物量大、磷含量高、對(duì)環(huán)境適應(yīng)能力強(qiáng)和易于種植等特點(diǎn)，克服了普通磷富集植物的不足；且礦山生態(tài)型粗齒冷水花地上部磷含量高達(dá)16.23 g/kg，非礦山生態(tài)型僅為6.09 g/kg，具有磷富集植物的優(yōu)勢(shì)；前期研究得出，高磷條件下，礦山生態(tài)型粗齒冷水花磷富集能力顯著高于非礦山生態(tài)型，是一種典型的磷富集植物[20-22]。本研究在前期研究基礎(chǔ)上，進(jìn)行土培試驗(yàn)，探討高磷處理下不同施氮量對(duì)礦山生態(tài)型粗齒冷水花磷富集特性的影響，明確最佳施氮量，以期為合理利用其提取土壤中過(guò)剩的磷提供理論依據(jù)。

1材料與方法

1.1　供試材料

供試植物：礦山生態(tài)型粗齒冷水花采自四川省什邡市磷礦區(qū)(104°50′ E, 30°25′ N)，非礦山生態(tài)型粗齒冷水花采自四川省雅安市雨城區(qū)(102°59′ E, 29°58′ N)。

供試土壤：采自四川省都江堰市白沙鎮(zhèn)的灰潮土，其基本理化性質(zhì)為：pH 6.53、速效磷(P)6.80 mg/kg、堿解氮69.04 mg/kg、速效鉀(K)24.90 mg/kg、有機(jī)質(zhì)18.15 g/kg。

供試肥料：尿素(N 46.60%)、磷酸二氫鉀(P2O552.16%、K2O 34.61%)，均為分析純。

1.2　試驗(yàn)設(shè)計(jì)與處理

試驗(yàn)設(shè)置0，70，140，210，280和350 mg N/kg土，共6個(gè)施氮量處理。施磷量為400 mg/kg，每處理重復(fù)5次，共60盆，完全隨機(jī)排列。采用土培盆栽，土壤風(fēng)干后，過(guò)2 mm篩混勻；每盆(14.5 L)裝土15 kg。磷配成溶液一次性施入土壤，充分混勻，陳化5周后，將尿素配成溶液加入土壤，混勻待用。陳化5周后土壤速效磷(P)：185.25 mg/kg。

兩種生態(tài)型粗齒冷水花幼苗于2013年5月上旬采集。幼苗的扦插管理采用劉霜等[20]的方法。待幼苗生長(zhǎng)30 d后，將長(zhǎng)勢(shì)一致的幼苗移栽至盆中，每盆種2株。采用自然光照，每周澆水4~5次，按田間持水量的70%確定灌水量，并記錄植株生長(zhǎng)狀況，及時(shí)除草、防治病蟲(chóng)害等。試驗(yàn)于2013年6月至10月在四川農(nóng)業(yè)大學(xué)教學(xué)科研園區(qū)有防雨設(shè)施的網(wǎng)室中進(jìn)行。

1.3　樣品采集與制備

于移栽后9周(花期)采樣，采樣時(shí)將整盆倒出，植株先用自來(lái)水沖洗，再用蒸餾水潤(rùn)洗，洗凈后用吸水紙擦干，任取一株，將其分為地上部和地下部，裝袋后在105℃殺青30 min，75℃烘干至恒重，稱重測(cè)定生物量，粉碎后過(guò)1 mm篩用于磷含量測(cè)定；另一株取根系經(jīng)液氮迅速固定后，保存于-80℃(Thermo Freezer 700, USA)冰箱，用于酸性磷酸酶和植酸酶活性的測(cè)定。

1.4　測(cè)定項(xiàng)目及方法

土壤基本理化性質(zhì)采用常規(guī)分析方法[23]；植株全磷測(cè)定采用H2SO4-H2O2消煮-釩鉬黃比色法[23]；酸性磷酸酶活性測(cè)定采用對(duì)硝基苯磷酸二鈉法[24]；植酸酶活性測(cè)定采用Starnes等[25]的方法。

1.5　數(shù)據(jù)處理

富集系數(shù)=植株磷含量/陳化后土壤有效磷含量[26]；遷移率=地上部磷積累量/植株磷積累量×100%[26]；采用Excel 2007、DPS 11.0進(jìn)行統(tǒng)計(jì)分析，Origin Pro 8.0進(jìn)行圖表制作。

2結(jié)果與分析

2.1　施氮量對(duì)兩種生態(tài)型粗齒冷水花生物量和磷積累量的影響

從表1可知，隨施氮量增加，粗齒冷水花地上部和地下部生物量均呈現(xiàn)先升高后降低趨勢(shì)，在140 mg/kg達(dá)最大值。礦山生態(tài)型地上部生物量在70，140和210 mg/kg施氮量下顯著高于對(duì)照，分別比對(duì)照增加60%，81%和46%；非礦山生態(tài)型地上部生物量在70，140和210 mg/kg顯著高于對(duì)照，分別比對(duì)照增加26%，63%和49%；各施氮量下礦山生態(tài)型地上部生物量均高于非礦山生態(tài)型，為非礦山生態(tài)型的1.36~3.47倍。礦山生態(tài)型地下部生物量?jī)H在140 mg/kg顯著高于對(duì)照，非礦山生態(tài)型地下部生物量在70~280 mg/kg均高于對(duì)照；礦山生態(tài)型地下部生物量隨施氮量變化小于非礦山生態(tài)型。其中，礦山生態(tài)型地下部生物量?jī)H在70和140 mg/kg低于非礦山生態(tài)型，在其余施氮量下均高于非礦山生態(tài)型。表明140 mg/kg施氮量能使礦山生態(tài)型粗齒冷水花地上部生物量增幅最大。

表1　施氮量對(duì)兩種生態(tài)型粗齒冷水花生物量的影響

注：ME表示礦山生態(tài)型，NME表示非礦山生態(tài)型；同列不同字母表示不同施氮量間差異顯著(P<0.05)，*表示不同生態(tài)型間差異顯著(P<0.05)，** 表示不同生態(tài)型間差異極顯著(P<0.01)。下同。

Note: ME means mining ecotypes, NME means non-mining ecotypes; Mean values labeled with different letters in the same column are significantly different (P<0.05) at different N supply. * means significantly different (P<0.05) at different ecotypes at the same N supply. ** means significantly different (P<0.01) at different ecotypes at the same N supply. The same below.

從表2可知，隨施氮量增加，粗齒冷水花地上部和地下部磷積累量先升高后降低，在140 mg/kg達(dá)最大值。其中，礦山生態(tài)型地上部磷積累量在70，140和210 mg/kg顯著高于對(duì)照，分別比對(duì)照增加29%，73%和41%；非礦山生態(tài)型在70，140和210 mg/kg顯著高于對(duì)照，分別比對(duì)照增加46%，76%和31%。各施氮量下礦山生態(tài)型地上部磷積累量均高于非礦山生態(tài)型，為非礦山生態(tài)型的1.34~2.59倍。礦山生態(tài)型地下部磷積累量?jī)H在140和210 mg/kg顯著高于對(duì)照，非礦山生態(tài)型在70，140和210 mg/kg顯著高于對(duì)照。除70和140 mg/kg施氮量外，礦山生態(tài)型地下部磷積累量均高于非礦山生態(tài)型。表明礦山生態(tài)型粗齒冷水花地上部和地下部磷積累量受施氮量影響較大，在140 mg/kg施氮量下其磷積累量最大。

表2　施氮量對(duì)兩種生態(tài)型粗齒冷水花磷積累量的影響

2.2　施氮量對(duì)兩種生態(tài)型粗齒冷水花磷富集系數(shù)和遷移率的影響

由表3可知，礦山生態(tài)型粗齒冷水花磷富集系數(shù)隨施氮量增加而升高，在350 mg/kg施氮量達(dá)最大值。各施氮量下礦山生態(tài)型磷富集系數(shù)均大于1，且高于對(duì)照。兩種生態(tài)型粗齒冷水花磷富集系數(shù)在不同施氮量下差異較小，表明適宜施氮可促進(jìn)礦山生態(tài)型粗齒冷水花對(duì)磷的吸收，增加植株生物量，而對(duì)其體內(nèi)磷含量有一定稀釋作用，導(dǎo)致富集系數(shù)差異較小。

遷移率能很好地反映粗齒冷水花向地上部轉(zhuǎn)移磷的能力。由表3可知，在不同施氮量下，礦山生態(tài)型粗齒冷水花磷遷移率均大于50%。除對(duì)照外，礦山生態(tài)型粗齒冷水花遷移率在不同施氮量下均高于非礦山生態(tài)型，在70和140 mg/kg處理下表現(xiàn)最為明顯。表明適宜增施氮肥能提高礦山生態(tài)型向地上部遷移磷的能力，增加植株對(duì)磷的積累。

表3　施氮量對(duì)兩種生態(tài)型粗齒冷水花磷富集系數(shù)和遷移率的影響

2.3　施氮量對(duì)兩種生態(tài)型粗齒冷水花根系酸性磷酸酶和植酸酶活性的影響

由圖1可知，在高磷(400 mg/kg)條件下，隨施氮量增加，礦山生態(tài)型粗齒冷水花根系酸性磷酸酶活性逐漸升高，植酸酶活性則先升高后降低，在140 mg/kg達(dá)最大值。各施氮量下礦山生態(tài)型根系酸性磷酸酶和植酸酶活性均顯著高于非礦山生態(tài)型(P<0.05)，分別為非礦山生態(tài)型的1.22~1.67倍和1.02~1.07倍。在70~350 mg/kg施氮量下，礦山生態(tài)型根系酸性磷酸酶活性分別比對(duì)照增加34%~281%，非礦山生態(tài)型根系酸性磷酸酶活性比對(duì)照增加23%~178%。礦山生態(tài)型根系植酸酶活性在施氮量為70，140和210 mg/kg時(shí)分別比對(duì)照增加3.80%，13.60%和8.40%，非礦山生態(tài)型根系植酸酶活性則比對(duì)照增加4.2%，10.0%和5.2%。表明高磷條件下，適宜施氮可顯著提高礦山生態(tài)型粗齒冷水花根系酸性磷酸酶和植酸酶活性。

圖1　施氮量對(duì)兩種生態(tài)型粗齒冷水花根系酸性磷酸酶(A)和植酸酶(B)活性的影響Fig.1　Effect of different N supply on the activities of apase (A) and phytase (B) in the root of two ecotypes of P. sinofasciata　ME表示礦山生態(tài)型，NME表示非礦山生態(tài)型；不同字母表示同種生態(tài)型不同施氮量間差異顯著(P<0.05)，* 表示同一處理不同生態(tài)型間差異顯著(P<0.05)，** 表示同一處理不同生態(tài)型間差異極顯著(P<0.01)。ME means mining ecotypes, NME means non-mining ecotypes; Mean values labeled with different letters in the same ecotypes are significantly different (P<0.05) at different N supply. * means significantly different (P<0.05) at different ecotypes at the same N supply. ** means significantly different (P<0.01) at different ecotypes at the same N supply.

3討論

目前，有關(guān)富磷植物的研究主要集中在不同植物品種和同一品種不同基因型或生態(tài)型間富磷能力比較等方面[27-32]，對(duì)如何提高其磷富集潛力的研究較少；況且報(bào)道的富磷植物多為陸生植物，對(duì)于既適合陸生又適合濕生的植物研究較為缺乏。粗齒冷水花是一種多年生草本植物，廣泛分布于中國(guó)大陸南方地區(qū)的路邊、河邊和山坡上，可陸生和濕生，具有生物量大、磷含量高、根系分布深、對(duì)環(huán)境適應(yīng)能力強(qiáng)、可連續(xù)多年提取等優(yōu)點(diǎn)。前期土培試驗(yàn)表明，高磷處理下的礦山生態(tài)型粗齒冷水花對(duì)磷的富集能力較強(qiáng)[20]，其磷富集潛力遠(yuǎn)高于非礦山生態(tài)型粗齒冷水花、向日葵(Helianthusannus)、黃南瓜、Marshall和Gulf黑麥草等磷富集植物[9,13]。本研究在前期研究的基礎(chǔ)上進(jìn)一步揭示了施氮量對(duì)高磷處理下的兩種生態(tài)型粗齒冷水花磷富集潛力的影響。相關(guān)研究表明，合理施氮可促進(jìn)甜瓜(Cucumismelo)[33]、飼草玉米(Zeamays)[34]、百喜草和扁穗牛鞭草[14]地上部的生長(zhǎng)，增加收獲部分生物量；不合理施氮?jiǎng)t會(huì)引發(fā)氮肥增產(chǎn)效益降低，對(duì)植物生長(zhǎng)產(chǎn)生毒害等問(wèn)題。本研究中，在140 mg/kg施氮量下，礦山生態(tài)型生物量達(dá)36.25 g/株，遠(yuǎn)高于非礦山生態(tài)型(29.13 g/株)以及相同磷濃度和同一采樣時(shí)期下的礦山生態(tài)型生物量(4.49 g/株)[21]；當(dāng)施氮量超過(guò)140 mg/kg，生物量顯著下降，表明適宜施氮可有效提高礦山生態(tài)型生物量，不合理施氮?jiǎng)t會(huì)對(duì)植株產(chǎn)生毒害，進(jìn)而降低其生物量。

施氮不僅會(huì)影響植物的生長(zhǎng)，也會(huì)影響植物對(duì)養(yǎng)分的吸收積累。湯明堯等[35]研究表明，施氮可促進(jìn)加工番茄(Lycopersiconesculentum)植株對(duì)磷的吸收，各施氮處理下的磷積累量為對(duì)照的1.49~2.63倍；有關(guān)甜瓜[33]和雜交棉(Gossypiumhirsutum)[36]等的研究指出，適宜增施氮肥可有效提高植株磷積累量，過(guò)量施氮?jiǎng)t不利于植株磷的積累。本研究中，在0~140 mg/kg施氮范圍內(nèi)，高磷處理下的礦山生態(tài)型粗齒冷水花植株磷積累量逐漸增加；當(dāng)施氮量高于140 mg/kg，礦山生態(tài)型磷積累量顯著下降；表明在0~140 mg/kg范圍內(nèi)施氮可顯著提高礦山生態(tài)型粗齒冷水花磷積累量，過(guò)量施氮?jiǎng)t會(huì)影響植株磷積累。植物修復(fù)的高效率表現(xiàn)在通過(guò)地上部帶走污染物的總量[6]，礦山生態(tài)型地上部和整株磷積累量在140 mg/kg施氮量下可達(dá)223.73和259.82 mg/株，非礦山生態(tài)型達(dá)159.79和202.22 mg/株，遠(yuǎn)高于相同磷濃度和同一采樣時(shí)期下的礦山生態(tài)型整株磷積累量(30.25 mg/株)[21]；而高磷(豬糞)處理下礦山生態(tài)型粗齒冷水花整株磷積累量?jī)H為99.40 mg/株[22]；可水陸兩生的水蓼(Polygonumhydropiper)在高磷條件下磷積累量也僅為114.88 mg/株[26]；用于污水修復(fù)的鳳眼蓮(Eichhorniacrassipes)和粉綠狐尾藻(Myriophyllumaquaticum)體內(nèi)磷積累量最高也僅為80.13和38.72 mg/株[37]。迄今為止研究最為深入的牧草Ptilotus[38]、Marshall和Gulf黑麥草[9-10],在高磷處理下的地上部磷積累量也僅能達(dá)到120，29.33和29.70 mg/盆，遠(yuǎn)低于本研究中的礦山生態(tài)型粗齒冷水花的單株磷積累量。因此，適宜增施氮能顯著提高礦山生態(tài)型粗齒冷水花磷積累量，強(qiáng)化其富磷潛力。植物根系分泌酸性磷酸酶是提高有機(jī)磷在土壤中的生物有效性的重要途徑之一[39-40]，植酸酶是對(duì)植酸鹽類具有高度的專一性的磷酸單酯水解酶，為肌醇與磷酸(鹽)一類酶的總稱[12, 24]，對(duì)植酸鹽類具有高度的專一性。根系分泌酸性磷酸酶被認(rèn)為是植物適應(yīng)低磷脅迫的一種機(jī)制[41-43]。然而，研究得出，高磷處理下的富磷植物黃瓜、黃南瓜[13]、水蓼[26]、Duofestulolium[10,24]、Marshall和Gulf黑麥草[9-10]等的根系酸性磷酸酶和植酸酶活性均高于對(duì)照；葉代樺等[26]認(rèn)為，富磷植物水蓼體內(nèi)較高的酸性磷酸酶和植酸酶活性是其對(duì)磷富集的機(jī)理之一。本研究中，高磷處理下的粗齒冷水花酸性磷酸酶活性隨施氮量增加而升高，植酸酶活性則先升高后降低，表明適宜施氮可顯著提高高磷處理下的粗齒冷水花根系酸性磷酸酶和植酸酶活性，增加植物對(duì)磷的富集；礦山生態(tài)型根系酸性磷酸酶和植酸酶活性始終高于非礦山生態(tài)型，說(shuō)明各施氮量下礦山生態(tài)型粗齒冷水花對(duì)磷的富集作用更強(qiáng)。以上研究表明，礦山生態(tài)型粗齒冷水花在適宜施氮量下的生長(zhǎng)狀況更佳，比非礦山生態(tài)型以及普通富磷植物更具磷富集優(yōu)勢(shì)。除多次收獲和暖冷季混種等方式外，適宜施氮亦可有效提高植物對(duì)磷的富集潛力。

4結(jié)論

隨施氮量的增加，礦山生態(tài)型粗齒冷水花生物量和磷積累量先升高后降低，在140 mg/kg施氮量下達(dá)最大值。其中，礦山生態(tài)型地上部和整株磷積累量達(dá)223.73和259.82 mg/株。各施氮量下礦山生態(tài)型生物量和磷積累量均高于非礦山生態(tài)型。礦山生態(tài)型磷富集系數(shù)隨施氮量增加而增加，磷遷移率均高于50%。與非礦山生態(tài)型相比，礦山生態(tài)型對(duì)磷的富集潛力更大。

礦山生態(tài)型根系酸性磷酸酶和植酸酶活性分別在350和140 mg/kg達(dá)峰值，且各施氮量下礦山生態(tài)型根系酸性磷酸酶活性和植酸酶活性均顯著高于非礦山生態(tài)型。在140 mg/kg施氮量下，高磷環(huán)境中的礦山生態(tài)型粗齒冷水花根系較高的酸性磷酸酶和植酸酶活性是其高效積累磷的原因之一。

本研究發(fā)現(xiàn)，140 mg/kg為最佳施氮量，該施氮量下礦山生態(tài)型粗齒冷水花的長(zhǎng)勢(shì)和磷富集潛力均最優(yōu)。

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