不同pH處理對澳洲堅果幼苗生長及生理特性的影響

中圖分類號：S664.9文獻標志碼：A

Effects of Different pH Treatments on Growth and Physiological Characteristics of Macadamia integrifolia

HUAN XiuJu， QIN XiaoMin， PAN HaoNan， YANG XiaoZhou， PAN ZhenZhen， WEI ZheJun， HE XianYang， WANG WenLin， ZHENG ShuFang， TAN QiuJin* （Guangxi South Subtropical Agricultural Scientific Research Institute， Chongzuo， Guangxi 532415， China）

Abstract： 【Objective】 This study aimed to investigate the tolerance of macadamia （Macadamia integrifolia） seedlings to acid stress.【Method】 This study used the seedlings of M. integrifolia variety H2 as test materials and conducted a pot sand culture experiment treated with different pH levels （3，4，5，6），and the treatment with pH 6 was used as the control （CK）.The growth and physiological characteristics of macadamia seedlings were analyzed at after treatment.【Result】 The research results showed that， after 90 d of acid stress treatment， the growth of macadamia plants was significantly inhibited， and plant height （PLH），leaf area （LA）， shoot dry weight （SDW） and root dry weight （RDW） of macadamia seedlings showed an extremely significantly decrease （Plt;0.01） .The acid stress significantly inhibited ground diameter （GD） （Plt;0.05） . Compared with that of CK， the GD under pH 5， pH 4， and pH 3 conditions decreased by 5.7% ， 7.3% ，and 13.5% ，respectively. The acid stress did not significantly influence root-shoot ratio （RSR）. The chlorophyll content determination showed that acid stress extremely significantly reduced the chlorophyll a content （CAC） and total chlorophyll content， but had no significant effect on chlorophyll b content. The physiological characteristics analysis of root showed that， under acidic conditions， the content of soluble protein and malondialdehyde （MDA） showed an extremely significant decrease，while the content of abscisic acid （ABA） extremely significantly increased. Compared with CK， the ABA content in the treatments with pH 3， pH 4 and pH 5 extremely significantly increased by 19.3% 。 58.6% ，and 73.9% ，respectively. At the same time， the activities of superoxide dismutase （SOD）， peroxidase （POD） and catalase （CAT） allsignificantly decreased， and especially， the SOD activity extremely significantly decreased by 29.5% 。 43.3% ，and 60.7% ，respectively， compared with that in CK. The correlation analysis showed that the absolute value of correlation coefficients among all indicators were greater than O.4， indicating a moderate or higher correlation. The absolute value of correlation coefficients between PLH and the other 14 indicators were all greater than 0.6， showing a strong correlation and PLH had an extremely positive correlation with CAC and SOD. GD had an extremely positive correlation with the activity of SOD， POD， CAT and MDA content， and a moderately positive correlation with RSR. The absolute value of correlation coefficients between SDW and the other 14 traits were all greater than O.8， indicating a strong correlation.The absolute value of correlation coefficients between RDW and other traits were all greater than 0.7， indicating a strong correlation.The absolute value of correlation coefficients between ABA and the other 14 indicators were all greater than 0.7， showing a strong correlation.【Conclusion】 Acid stress inhibits the growth of macadamia seedlings， significantly reduced the PLH， LA， SDW， RDW， and GD but showed no significant effct on root-shoot ratio.Macadamia seedlings might enhance their resistance to external acid stress by regulating plant hormones （ABA）， osmoregulatory substances （soluble proteins， MDA）， and enzyme activity.

Keywords： Macadamia integrifolia； sand culture； pH value； morphological traits； physiological characteristics

0 引言

【研究意義】根據全國土壤調查結果，我國土壤pH值為 ，以 為主（韓天富等，2020）。廣西地處歐亞大陸南緣，屬于熱帶亞熱帶季風氣候區，區內pH值為 的紅壤分布范圍較廣（劉康懷等，2000）。澳洲堅果（Macadamia inte-grifolia）又稱夏威夷果，為山龍眼科澳洲堅果屬喬木（黃忠權等，2022），其果仁含有豐富的不飽和脂肪酸、蛋白質、氨基酸、可溶性糖、膳食纖維和礦物質等營養成分，具有較好的保健功能（劉錦宜等，2018）。因澳洲堅果經濟價值高，可作為鄉村振興的支柱產業，正被越來越多的熱帶亞熱帶適種區國家和地區栽種（王文林等，2022；萬繼鋒等，2024）。我國從20世紀90年代末開始引種試種澳洲堅果，目前主要分布在云南、廣西、廣東、貴州等省（區）（王文林等，2018）。澳洲堅果的主要栽培地多為偏酸性的土壤，雖然澳洲堅果對酸脅迫具有一定的耐受性，可在一定酸脅迫環境下生長，但過酸性土壤不利于澳洲堅果的生長發育。因此，研究酸脅迫對澳洲堅果幼苗生長和生理特性的影響，對于探索當地酸化土壤高效栽培模式，提高土地利用率，同時提高澳洲堅果的經濟產量具有重要意義。【前人研究進展】目前，在澳洲堅果種苗繁育方面，有組織培養研究（郭凌飛等，2010）；在種質資源方面，有不同品種開花結實率研究（陳海生等，2017）、種質光合特性比較研究（宮麗丹等，2019）、土壤養分與果實內含物相關性研究（鄭樹芳等，2021）、種質果實性狀及營養成分分析（譚秋錦等，2021）；在育種方面，有接穗輻射誘變育種研究（孔廣紅等，2016）、基因克隆與功能分析（王文林等，2020）和轉錄組測序分析脂肪酸合成（劉紫艷等，2022）；……