Liquidambar formosana Hance is a pinene-rich deciduous plant species in the Altingiaceae family that is used as a medicinal plant in China. However, the regulatory mechanisms underlying α-pinene and β-pinene biosynthesis in L. formosana leaves remain unknown. Here, a joint analysis of the volatile compounds and transcriptomes of L. formosana leaves was performed to comprehensively explore the terpene synthase (TPS) that may participate in α-pinene and β-pinene biosynthesis. Headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS) jointly detected volatile L. formosana leaves. Trees with high and low levels of both α-pinene and β-pinene were defined as the H group and L group, respectively. RNA sequencing data revealed that DXR (1-deoxy-D-xylulose-5-phosphate reductoisomerase), HDS [(E)-4-hydroxy-3-methylbut-2-eny-l-diphosphate synthase], and TPS may be the major regulators of monoterpenoid biosynthesis. We identified three TPSs (LfTPS1, LfTPS2, and LfTPS3), which are highly homologous to α-pinene and β-pinene synthases of other species in phylogenetic analysis. Four TPS genes (LfTPS1, LfTPS2, LfTPS4, LfTPS5) may be critically involved in the biosynthesis and regulation of α-pinene and β-pinene in L. formosana. Bioinformatic and transcriptomic results were verified using quantitative real-time PCR. We identified LfTPS1, LfTPS2 as candidate genes for α-pinene and β-pinene biosynthesis that significantly improve the yield of beneficial terpenoids.

[目的]筛选适合广东韶关地区林地种植的牧草.[方法]以山毛豆(Tephrosia candida)、木豆(Cajanus cajan)、甜象草(Pennisetum purpureum)、大叶菊苣(Cichorium intybus)、糖蜜草(Melinis minutiflora P.Beauv.)和晚熟狼尾草(Pennisetum alopecuroides)为试验材料,通过测株高、生物量、粗蛋白、粗脂肪、粗纤维、粗灰分等指标,评价6种牧草营养指标的差异性.[结果]播种后90 d晚熟狼尾草株高达到250 cm,甜象草为180 cm,木豆和山毛豆分别为150和120 cm;晚熟狼尾草和甜象草鲜草产量分别达到172470和176415 kg/hm2;山毛豆蛋白含量最高,达17.0％,木豆为15.3％;木豆的粗脂肪含量最高,达4.1％,其次为大叶菊苣(3.5％).[结论]山毛豆和糖蜜草更适合林下种植,而甜象草和晚熟狼尾草虽然产量大,但株高较高可能会对其他林地经济作物造成影响,更适合在成熟林下种植.

通过比较不同地区的无瓣海桑Sonneratia apetala人工林土壤理化指标特征,探讨无瓣海桑人工林不同深度土壤理化性质的变化规律及其相关性.以广东珠海淇澳岛红树林自然保护区与台山市烽火角两个地区的无瓣海桑人工林为例,测定土壤深度0～100 cm垂直方向上总氮、总磷、pH、电导率、有机碳含量等理化指标,并进一步分析其相关性.结果表明,淇澳岛的土壤理化指标总氮、总磷、含盐量、电导率、有机碳和容重等在垂直方向上的变化较烽火角的平缓,其中烽火角的土壤含盐量、pH均显著高于淇澳岛;淇澳岛的土壤总氮与电导率却高于烽火角.在0～15 cm和15～30 cm土层,烽火角的有机碳含量显著高于淇澳岛,在30～100 cm土层则显著低于淇澳岛.烽火角土壤总氮与含盐量呈显著负相关,与pH呈显著正相关.淇澳岛土壤总氮含量与含盐量呈极显著负相关,与pH呈极显著正相关,且有机碳含量与含盐量、pH呈显著相关性.