Intercropping systems improve crop productivity through enhanced biodiversity and ecosystem functioning; however, we lack an understanding of how intercropping influences biodiversity across multiple trophic levels. This research focuses on the effects of intercropping in orchards, a practice where different crops are grown together, compared to traditional monoculture systems. The aim is to understand how intercropping influences biodiversity in both aboveground and belowground ecosystems across China. Utilizing a meta-analysis approach, the study evaluates data from 567 observations across 50 studies in China. It assesses the impacts of intercropping on various groups, including pests, predators, and parasitoids aboveground, and bacteria, fungi, and soil fauna belowground. The study also considers the role of different orchard management practices, such as types of intercropping and pesticide use. Findings show that intercropping substantially boosts biodiversity. Belowground biodiversity benefits more (abundance increased by 39 %, richness by 20 %). Specifically, aboveground predators and parasitoids see a 67 % and 29 % increase in abundance, respectively, while richness of predators increased by 11 %. Belowground fungi increased by 30 % in abundance and bacteria increased by 3 % in Shannon diversity, while soil fauna abundance and richness increased by 76 % and 29 %, respectively. Notably, the combination of fruit with grass or flowers and minimizing pesticide application proved most beneficial. Overall, our finding provides robust evidence for the positive crop diversification-biodiversity relationships in orchards across China, emphasizing that intercropping is a promising way to conserve natural enemies, soil microbial and soil fauna diversity and may contribute to biocontrol, soil improvements and crop yields.

There are differences in the litter quality and decomposition rate of kiwifruit varieties, but it is not clear whether these differences are related to microbial communities. The leaf litters of two kiwifruit varieties (A. chinensis cv ‘Hongyang’ and A. chinensis cv ‘Jinyan’) were taken as objects, and the structure, diversity, and succession of the soil microbial communities were analyzed using an in situ decomposition experiment. Moreover, the contents of C, N, P, and K in the litters during decomposition were analyzed. The results show that there were variety differences in community structure at the generic level. Lophotrichus, Acaulium, and Fusarium were relatively more abundant in the microbial community of the ‘Hongyang’ kiwifruit litter, and Humicola and Tausonia were relatively more abundant in the microbial community of the ‘Jinyan’ kiwifruit litter. Subgroup_6 and Sphingomonas were the dominant bacteria. The bacterial community diversity of ‘Jinyan’ kiwifruit was higher than that of the ‘Hongyang’ kiwifruit litter. The community diversity was higher in the middle and later periods. The contents of C and N in the litters were the main factors affecting microbial communities. The abundances of Humicola and Apiotrichum were negatively correlated with the contents of C and N, and the abundances of Sphingomonas and SC-I-84 were positively correlated with the content of C. There were variety differences in the microbial communities corresponding to the decomposition processes of the ‘Hongyang’ and ‘Jinyan’ kiwifruit litters. The mechanisms of the variety differences were related to litter quality and the initial soil microbial community.

为明确CPPU处理对猕猴桃果实生长发育及采后品质的影响,以猕猴桃黄肉品种"金艳"为试验材料,于盛花后30 d采用10 mg/L CPPU进行幼果浸果处理,自然生长果实为对照,测定生长发育期、常温处理(20℃)与低温贮藏(1℃)的果实品质指标动态变化.结果表明:(1)与对照相比,10 mg/LCPPU处理在采收时明显提高了果实内外品质指标,促进了果实提早成熟.其中单果质量与纵横侧径分别提高了 11.35％、7.20％、6.21％与7.08％;蔗糖含量提高了 12.93％;可溶性固形物、干物质与果糖含量高于对照,但差异不显著.(2)在20℃常温处理下,经CPPU处理的果实采后达到可食状态时可溶性固形物、果糖、蔗糖含量比对照显著提高了 10.74％、3.34％、4.42％;同时促进了呼吸高峰的提前,缩短了货架期.(3)在1℃低温贮藏末期,经CPPU处理的果实采后可溶性固形物、果糖、葡萄糖含量比对照显著提高了 13.11％、7.23％、11.11％,且果实硬度下降加快,缩短了采后贮藏保鲜期.综上所述,10 mg/L CPPU处理显著提高了果实单果质量,提升果实内在品质,同时加快了果实成熟进程,缩短了果实成熟期及采后贮藏保鲜期.

The aim of this study was to reveal the decomposition dynamics of kiwifruit litter and verify the variety differences and provide a scientific basis for rational fertilization in orchard. Kiwifruit litters of two varieties (‘Hongyang’ and ‘Jinyan’) were taken as the objects; the litter decomposition rate, the dynamics of macro-elements and micro-elements, and soil enzyme activities during the decomposition process were analyzed. The results showed that the litter decomposition rate of ‘Hongyang’ kiwifruit was faster than that of ‘Jinyan’ kiwifruit, because of the higher initial N and P content in the litter of the ‘Hongyang’ kiwifruit. The dynamic trends of macro-elements and micro-elements during litter decomposition of two varieties were similar. The C content was relatively stable, the P content was fluctuant, and the K content was decreasing. The contents of N, Fe, Mn, Cu, and Zn were increasing. The contents of Ca, Mg, and B increased first and then decreased. After 180 days of the decomposition experiment, more than 75% of the initial contents of C, N, P, K, Ca, Mg, and B were released. The dynamic trends of the soil enzyme activities of two varieties were generally similar. Due to the slow decomposition rate, the dynamic trends of soil enzyme activities of ‘Jinyan’ kiwifruit litter each showed hysteresis. The contents of Ca, Mg, and Mn were significantly correlated with some soil enzyme activities. In conclusion, the litter substrate quality of the two kiwifruit varieties is different, which leads to the difference in the decomposition rate. The litter decomposition of kiwifruit is an important supplement to the macro-element in orchard soil.

The aim of this study was to reveal the decomposition differences of kiwifruit litters with different qualities and verify the “Initial Litter Quality Hypothesis”. This study took litters of ‘Jinkui’ and ‘Hort-16A’ kiwifruit as the research objects, and carried out in situ decomposition experiments. The decomposition rate, nutrients release process, and soil enzyme activities were analyzed. In this study, the litter of ‘Hort-16A’ kiwifruit decomposed faster than the litter of ‘Jinkui’ kiwifruit. The decomposition time was positively correlated with the initial concentration of C of the litters, but negatively correlated with the concentrations of N and P. Except for P and Mn, the dynamic trends of the nutrient concentrations were similar during the litter decomposition of ‘Jinkui’ and ‘Hort-16A’ kiwifruit. After 180 days of decomposition, about 85%~95% of the initial concentrations of the macro-elements of the ‘Hort-16A’ kiwifruit litter were released. The dynamic trends of protease activities were similar, but that of sucrase, β-1,4-glucosidase, polyphenol oxidase, and phosphatase were different. In conclusion, the litter quality of kiwifruit affects the decomposition rate, and the difference in decomposition rate in turn affects the dynamic processes of nutrient release and soil enzyme activity. This study provides evidence for the “Initial Litter Quality Hypothesis” in the orchard ecosystem.

Kiwifruit is a climacteric fruit, in which the accumulation of flavor substances mainly occurs at the postharvest ripening stage. However, the dynamic changes in metabolite composition remain poorly understood. Here, targeted multi-platform metabolome analysis based on GC-MS and UPLC-MS/MS and enzyme activity analysis were performed at different postharvest ripening stages of kiwifruit. A total of 12 soluble sugars and 31 organic acids were identified. The main soluble sugars are sucrose, glucose and fructose, which exhibited similar variation tendencies along with the extension of ripening. The main organic acids are citric acid, quinic acid and malic acid, which showed different variation patterns. A total of 48 energy metabolites were identified, which were classified into two groups based on the content variation. The content of substances related to the respiratory metabolic pathway decreased gradually along with postharvest ripening, and there was obvious accumulation of downstream products such as amino acids at the late ripening stage. A total of 35 endogenous hormones were identified, among which seven cytokinins were highly accumulated at the later stage of softening. We further investigated the dynamic changes in the activities of 28 ripening-related enzymes. As a result, the activities of 13 enzymes were highly correlated with changes in starch, total pectin, and soluble sugars, and those of seven enzymes were closely associated with the change in firmness. In conclusion, this study comprehensively describes the dynamic changes in soluble sugars, organic acids, hormones, energy substances, and ripening-related enzyme activities during kiwifruit postharvest ripening, and provides a theoretical basis for the postharvest quality improvement of kiwifruit.

【Objective】Fruit tree pruning is one of the most common management measures in orchards. However, very few studies focus on the decomposition process and nutrient release of pruned branches after returning to the field, and the mechanism of the effect of branch substrate quality on decomposition rate is not clear. The decomposition and nutrient release process of pruned kiwifruit branches were quantitatively analyzed to reveal the mechanism of the influence of branch substrate quality on decomposition rate, and to provide reference for scientific fertilization in kiwifruit orchard.【Methods】The pruned branches of four varieties of kiwifruit（Hongyang, Jinyan, Jinkui, and Hort-16A） were taken as the experimental materials. The in-situ decomposition experiment of kiwifruit branches was carried out in a 10-year orchard covering an area of 15 ha using decomposition bag method. In December 2020,after the trees were pruned, the branches pruned off were collected, dried at 60 ℃ to constant weight,and 15 g branch samples were weighed and put into decomposition bags. The decomposition experiment was started in early January 2021. According to the property that the decomposition rate of litters declines with time, the decomposition bags were sampled in the first, second, fifth, eighth and twelfth months of decomposition. The decomposed residue with the sampled bags was dried at 60 ℃ to constant weight and weighed. At the same time, the nutrient content in the residue was analyzed. The contents of total carbon and total nitrogen were determined with an elemental analyzer; total phosphorus was determined with an ultraviolet spectrophotometer; total potassium was measured with a flame photometer. The contents of lignin and cellulose were determined with the ammonium ferrous sulfate titration method after potassium dichromate oxidation, and the content of hemicellulose with the copper-iodine method. Based on the residual amount and decomposition time, the Olson decomposition model was used to fit the decomposition process and calculate the decomposition rate. Based on the dynamics of the contents of nutrients, lignin, cellulose, and hemicellulose during the decomposition process, the residues of nutrients and other substances, the relative nutrient return index, and the degradation rate of lignin and other substances were calculated. Moreover, the correlation between substrate quality and decomposition rate was analyzed.【Results】The results showed that the decomposition rates of pruned branches of the four kiwifruit varieties were in the order from fast to slow of Hongyang＞Hort-16A＞Jinyan＞Jinkui. Specifically, the half-life of Hongyang branch being decomposed was 5.2 months, and the turnover period was 26.6 months. The half-life for Hort-16A branches was 6.2 months, and the turnover period 26.7 months. The half-life for Jinyan branches was 6.4 months, and the turnover period 29.7months. The half-life for Jinkui branches was 7.2 months, and the turnover period 31.1 months. Among the four varieties, the contents of potassium and hemicellulose in Hongyang were the highest, while its contents of lignin and cellulose were the lowest. The contents of phosphorus in Jinyan, and nitrogen and lignin in Jinkui were the highest. The cellulose content of Hort-16A was the highest, while its contents of phosphorus and hemicellulose were the lowest. The initial nitrogen, potassium, lignin and hemicellulose contents of the litters were significantly correlated with the decomposition half-life. The initial content of carbon in the branches of the four varieties was similar, ranging from 36% to 38%. During the decomposition process, the carbon content was in a relatively stable state, indicating that carbon was gradually released with the decomposition of the dry matter. The initial content of nitrogen of Jinkui was 1.71%, and the content of nitrogen gradually decreased with the decomposition of the litters, suggesting release of nitrogen. The initial content of nitrogen of Hongyang, Jinyan, and Hort-16A was low,ranging from 0.7% to 0.9%. With the decomposition of the litters, the content of nitrogen increased gradually, indicating enrichment of nitrogen. The initial content of phosphorus of the four varieties was similar, ranging from 0.09% to 0.2%. With the decomposition of the litters, the content of phosphorus fluctuated, indicating that phosphorus release and accumulation occurred during the decomposition process. The initial content of potassium of Hongyang and Jinyan was higher than that in the other two varieties, ranging from 0.4% to 0.55%. With the decomposition process, potassium decreased gradually suggesting a gradual release of the element. The initial content of potassium of Jinkui and Hort-16A was0.08%-0.14%. With the decomposition process, potassium of Jinkui gradually increased. The potassium content of Hort-16A decreased within the first month of decomposition experiment, and then remained relatively stable. After twelve months of decomposition, branches of the four kiwifruit varieties released about 50%-70% of carbon and nitrogen, and Hongyang and Jinyan branches had a phosphorus and potassium release rate of more than 80%. Lignin, cellulose, and hemicellulose degraded gradually, and the degradation rate was the highest in the first month. Lignin degradation in Hongyang was the fastest, followed by Hort-16A and Jinyan, and that of Jinkui was the slowest, consistent with the decomposition rate of dry matter.【Conclusion】The decomposition half-life of kiwifruit branches is about six months,and the turnover period is about twenty-nine months. The decomposition of branches of kiwifruit trees is an important supplement to soil fertility. The decomposition characteristics of branches of fruit trees differ among varieties. The substrate quality is the main factor affecting the decomposition rate, and the lignin content plays the largest role in limiting the decomposition rate. The lignin content in Hongyang branches was the lowest and the decomposition rate was the highest, while the lignin content in Jinkui branches was the highest and the decomposition rate was the lowest.

[Objective]The temperature management during the softening process of post-harvest kiwifruit directly affects the flavor quality of the fruit and affects consumers “ready-to-eat” kiwifruit. [Method]In this study， the Actinidia chinensis ‘Jinyan’， which is mainly planted in Jiangxi Province， was used as the experimental material， and the starch degradation of post-harvest fruits and conversion to ready-to-eat type were taken as the entry point. The post-harvest fruit quality and starch degradation characteristics for kiwifruit were studied by different temperature treatments （5℃， 10℃， 20℃ and 30℃）. [Results]（1） The higher the treatment temperature was， the faster the fruit firmness and starch content decreased， and the faster the soluble solid content and decay rate increased; the too high temperature will affect the quality for ready-to-eat. Low temperature （5℃） had the least effect on fruit ripe and quality. 10℃ maintained fruit quality and effectively reduced post-harvest loss， and SSC content reached 16.15% in the soft ripening stage. The fruits treated at 20℃ had better ripening quality， but the rot rate was significantly higher than that treated at 10℃. At high temperatures （30℃）， the firmness decreased rapidly， the rot rate was as high as 20.67%， the SSC content was only 14.28% at the soft ripening stage， and the quality of fruit post-ripening decreased. （2） After different temperature treatments， 14 significantly differentially expressed genes related to starch and sucrose metabolism were screened out by transcriptome analysis. The transcriptome data were verified by RT-qPCR， and the transcriptome data were real and reliable. [Conclusion]Different temperature management had different effects on the post-ripening process of kiwifruit. Storage at 5℃ within the experimental temperature could prolong the storage period， and PHS2.1 specifically responded to 5℃ expression. Treatment at 10℃ could improve fruit quality and effectively reduce post-harvest loss， PHS2， BAM3.2 and BAM3L were expressed at 10℃. High temperature treatment fruit softening faster， incomplete conversion of starch， fruit quality is poor.

兴安杜鹃（Rhododendron dauricum）是大兴安岭森林群落灌木层的优势种，其种群统计研究尚属空白。以大兴安岭呼中区不同海拔和林型的兴安杜鹃种群为对象，编制了静态生命表，计算生存分析函数，采用时间序列分析种群数量动态。结果表明，低海拔梯度（600m）的落叶松林中，兴安杜鹃幼龄级（Ⅰ—Ⅱ）个体较多，占67.31%,且幼龄级死亡率和消失率较低，存活率较高，存活曲线为DeeveyⅠ型曲线，为增长型种群。种群的衰退期转折点在Ⅱ—Ⅲ龄级，未来种群数量呈增长趋势。中低海拔梯度（600—900m）的白桦林中，中龄级（Ⅱ—Ⅲ）个体数量较多，占45%以上，中龄级死亡率和消失率较低，存活率较高，存活曲线为DeeveyⅠ型曲线，为稳定型种群。种群的衰退期转折点在Ⅲ—Ⅴ龄级之间，由于种群密度制约，未来种群数量逐渐趋于衰退。高海拔梯度（1200m）的落叶松林中，种群个体总数最少。其中，Ⅰ龄级个体数量最多，占33.52%,但死亡率和消失率较高，存活率较低，Ⅱ—Ⅴ龄级死亡率和消失率较低，存活率较高，存活曲线为DeeveyⅢ型曲线，为增长型种群，但增长趋势较弱。种群的衰退期转折点在Ⅴ龄级，未来种群数量呈增长趋势，但由于环境限制，种群数量更趋于稳定。可以认为，大兴安岭兴安杜鹃种群数量整体稳定。海拔和林型是影响兴安杜鹃种群数量的重要因素，海拔为600—900m,郁闭度为45%—50%的白桦林为兴安杜鹃的适宜生境，成为灌木层中的主要优势种。

阐述了采前和采后影响猕猴桃(Actinidia chinensis)贮藏保鲜的主要因素,对猕猴桃贮藏保鲜的化学技术、生物技术和复合保鲜技术进行了归纳总结,最后从促进猕猴桃产业健康发展的角度对贮藏保鲜的前景进行了展望,旨在为延长猕猴桃贮藏保鲜期提供参考.

[目的]为阐明猕猴桃果园土壤养分对果实品质形成的影响,探讨适宜生产优质'红阳'猕猴桃果园的土壤养分方案,为果园提质增效提供理论依据.[方法]对江西省奉新县5个10年生'红阳'猕猴桃果园土壤养分、果实品质进行测定,采用典型相关性分析、多元回归、线性规划等多元统计分析方法,筛选影响果实品质的主要土壤养分因子.[结果](1)5个供试果园土壤pH为4.74～5.11的酸性土壤,有机质含量与养分含量总体水平充足,其中有效态铁、有效态锰、有效态锌和有效态铜等微量元素含量处于高量水平.(2)相关性分析结果显示,果实品质受土壤养分种类及含量影响差异显著.果实外观指标、单果质量及内在品质指标(除可滴定酸外)与多数土壤养分因子呈不同程度的正相关,其中单果质量与交换性镁含量呈显著正相关,干物质含量与有效态铁、pH呈显著正相关,可溶性糖与交换性镁、有效铁含量及土壤水分呈正相关,抗坏血酸含量与速效钾、有效硼含量呈显著正相关.(3)典型相关性分析和多元回归分析显示,果实品质是土壤养分综合作用的结果,其中有效态铜含量对果实品质表现为负向效应影响,而交换性镁、有效硼、有效态铁、有机质含量及pH对果实品质提升具有正向促进效应.(4)通过线性规划求解出当果园土壤有机质含量大于20.47％、交换性镁为336.87～437.49 mg/kg、有效态铁为59.1 mg/kg、有效态铜为1.12～2.19 mg/kg、有效硼为1.58 mg/kg、pH为6.5时,'红阳'猕猴桃果实品质可达最佳.[结论]奉新县'红阳'猕猴桃果园中大量元素供给水平较高,微量元素含量充足,今后栽培管理应加强土壤pH调节,控制微量元素铜肥的施用,同时平衡施用镁、铁、硼肥等矿质养分,可达到提高果园产量、提升果实品质的目标.

为了解不同品种猕猴桃果实糖酸组分及含量差异,利用气相色谱-质谱联用(GC-MS)和超高效液相色谱-串联质谱(UPLC-MS/MS)技术对"红阳"、"金果"和"金艳"三个品种猕猴桃采收期和软熟期果实的可溶性糖和有机酸组分及含量进行测定与分析.共鉴定到12 种可溶性糖和31 种有机酸,采收期三种猕猴桃果实的蔗糖、果糖和葡萄糖含量无明显差异,软熟期则以葡萄糖和果糖为主."红阳"和"金果"猕猴桃采收期和软熟期的有机酸均以奎宁酸为主,"金艳"猕猴桃采收期以柠檬酸为主,软熟期则以奎宁酸为主.糖酸比分析结果表明"红阳"最甜,"金艳"适中,"金果"风味较淡.该研究结果可为猕猴桃品种的品质评价和采后保鲜技术的开发提供一定的数据基础.

为研究稀土元素镧对脐橙叶片抗氧化生理代谢的影响,以2年生纽荷尔脐橙为试验材料,通过叶片喷施浓度为50、150、300 mg/L的硝酸镧溶液,分别于喷施后0、2、4、8、12、24 h采集植株中上部当年生嫩叶,测定超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)和抗坏血酸氧化酶(APX)的活性,为探明稀土元素对脐橙品质形成提供理论依据.结果表明:不同浓度硝酸镧处理后0～24 h,脐橙叶片SOD活性均呈先升高后降低的趋势,浓度为150 mg/L时活性较高;50 mg/L硝酸镧处理能够有效提升叶片POD活性,且促进了活性峰值的提早出现;50 mg/L硝酸镧处理前期可促进CAT活性的升高,而300 mg/L硝酸镧处理后期可促进CAT活性的升高;叶片GR活性得到明显提高,浓度为300 mg/L时活性最高;叶片APX活性受到明显抑制,150 mg/L硝酸镧处理抑制效果更明显.不同处理时间对抗氧化酶活性的影响较大,3个硝酸镧处理的叶片SOD、GR活性均呈先升高后降低的趋势,均在处理后4 h出现活性高峰;而叶片POD、CAT、APX活性高峰各处理表现不同.硝酸镧处理脐橙叶片促进SOD活性升高、APX活性下降的适宜浓度为150 mg/L,促使POD和CAT活性增加的适宜浓度为50 mg/L,促使GR活性增加的适宜浓度为300 mg/L.综上所述,硝酸镧处理能够提高脐橙叶片的抗氧化能力,抗氧化酶和抗氧化剂共同作用,维持细胞内活性氧产生与消除及氧化还原的动态平衡,进而提高叶片的抗逆性,健康的叶片促进光合与代谢循环,最终提高植株的营养积累.

在农林复合经营的研究中,与森林和农田系统相比,果园系统受到的关注相对较少.然而,果园系统具有发展复合经营的空间和需求,且拥有人力和市场优势,因而果园复合模式得到持续发展.目前,果园复合经营主要有果草、果粮、果菜、果药、果菌、果花和果果模式等,在多个地区、多种果园开展研究和实践.复合经营可以改善果园气候和土壤环境,促进果树生长,提高经济效益和生态效益.构建科学的复合经营模式,应基于适应性、互惠性和收益性原则,并遵循生物学、生态学和经济学规律.在果园复合经营未来发展和研究中,应进一步丰富复合种植的植物种类,精准分析果园效益提升的关键因素,将成果进行标准化推广.

为进一步提高猕猴桃品质,促进产业发展,本文从萌芽期、花期、果实生长期和冬季休眠期系统总结了猕猴桃生长过程中的主要病虫害种类及防治策略,阐述了采后猕猴桃鲜果容易发生的主要病害与防治方法,进而归纳了农业、物理、化学和生物方面的综合防治措施,最后提出了猕猴桃产业发展过程中病虫害防治存在的问题和建议.

以2年生纽荷尔脐橙嫁接苗为材料,通过喷施50、150、300 mg/L的硝酸镧[La(NO3)3]溶液,清水作为对照(CK),测定喷施前(0 h)和喷施后(2、4、8、12、24 h)脐橙叶片中2种膜透性物质过氧化氢(H2O2)与丙二醛(MDA)含量及多酚氧化酶(PPO)活性的变化特性,阐明硝酸镧对脐橙叶片H2 O2和MDA含量及PPO活性的影响.结果表明,硝酸镧处理后,脐橙叶片H2 O2含量和PPO活性呈"先升高,后降低"的变化趋势.150和300 mg/L硝酸镧处理不仅明显降低了脐橙叶片H2 O2含量增加速度,延缓了H2 O2含量峰值出现时间,而且明显提高了脐橙叶片PPO活性,其中150 mg/L的效果较好.另外,50 mg/L硝酸镧处理后脐橙叶片MDA含量峰值与CK出现的时间相同,处理后24 h,脐橙叶片MDA含量比CK降低了30％,而150和300 mg/L处理则明显促进了脐橙叶片MDA含量的积累.因此,硝酸镧对脐橙叶片中H2 O2、MDA和PPO的影响符合"低促高抑"的效应,适宜的处理浓度为50～150 mg/L.

Human pressure on the environment and climate change are two important factors contributing to species decline and overall loss of biodiversity. Orchids may be particularly vulnerable to human-induced losses of habitat and the pervasive impact of global climate change. In this study, we simulated the extent of the suitable habitat of three species of the terrestrial orchid genus Cypripedium in northeast China and assessed the impact of human pressure and climate change on the future distribution of these species. Cypripedium represents a genus of long-lived terrestrial orchids that contains several species with great ornamental value. Severe habitat destruction and overcollection have led to major population declines in recent decades. Our results showed that at present the most suitable habitats of the three species can be found in Da Xing’an Ling, Xiao Xing’an Ling and in the Changbai Mountains. Human activity was predicted to have the largest impact on species distributions in the Changbai Mountains. In addition, climate change was predicted to lead to a shift in distribution towards higher elevations and to an increased fragmentation of suitable habitats of the three investigated Cypripedium species in the study area. These results will be valuable for decision makers to identify areas that are likely to maintain viable Cypripedium populations in the future and to develop conservation strategies to protect the remaining populations of these enigmatic orchid species.

为了探明稀土元素镧对脐橙叶片渗透调节的影响,本研究以2年生'纽荷尔'脐橙为试验材料,采用0 mg/L(CK)、50 mg/L、150 mg/L和300 mg/L硝酸镧溶液喷施脐橙叶片,分别于喷施后0、2、4、8、12、24 h采集植株中上部当年生嫩叶,测定渗透物质可溶性糖、可溶性蛋白与游离脯氨酸含量.结果表明:不同生长时间,脐橙叶片(CK)可溶性蛋白含量积累先升高后降低,可溶性糖和游离脯氨酸含量积累持续降低;喷施不同浓度硝酸镧溶液后,脐橙叶片游离脯氨酸含量的积累趋势发生改变.当喷施50 mg/L和150 mg/L的硝酸镧时,可同时促进脐橙叶片中可溶性糖、可溶性蛋白与游离脯氨酸含量的积累;当浓度提高到300 mg/L时,叶片可溶性糖和游离脯氨酸含量的积累明显高于其他处理,但可溶性蛋白含量的积累明显受到抑制.由此可见,喷施硝酸镧后,脐橙叶片通过主动积累可溶性糖、可溶性蛋白与游离脯氨酸来适应和调节细胞渗透胁迫;由于渗透物质种类的不同,导致促进其含量积累的适宜浓度存在差异,其中适宜可溶性蛋白含量积累的浓度为≤150 mg/L;适宜可溶性糖和游离脯氨酸含量积累的浓度为≥300mg/L.研究结果可为进一步研究稀土元素对脐橙渗透物质影响的作用机理及生理代谢的调控提供参考依据.

Secondary metabolites in the leachates of medicinal herbs inhibit forest litter decomposition, affecting interspecific relationships and nutrient cycling in the silvi-medicinal system. In this study, a typical forest species in the Qinling Mountains area, Catalpa fargesii Bur., and nine species of common understory medicinal herbs were used as example species. A litter decomposition experiment was carried out by treating the C. fargesii litter with stem and leaf leachates (simulated using water extracts) from the medicinal herbs to investigate the effects on forest litter decomposition, nutrient release and soil enzyme activity. Lachates from Mentha haplocalyx Briq., Houttuynia cordata Thunb., Gynostemma pentaphyllum (Thunb.) Makino and Prunella vulgaris L. exhibited significant inhibitory effects on the decomposition and nutrient release of C. fargesii litter and on the activities of related soil enzymes. Consequently, it is suggested that plantation of these four medicinal herb species should be avoided under C. fargesii forests or interplanting density must be low to reduce inhibitory effects on litter decomposition and nutrient release.

[Objective] The effects of leachates from understory medicinal plants on decomposition of Pinus tabuliformis litter and soil enzyme activities were investigated to provide scientific basis for selecting suitable understory species.[Method] In this paper,and the effects of 9 leachates (water-extraction solution) from the stems and leaves of common medicinal plants (Taraxacum mongolicum,Corydalis bunF eana,Mentha haplocalyx,Houttuynia cordata,Asarum sieboldii,Nepeta cataria,Lonicera japonica,Gynostemma pentaphyllum and Prunella vulgaris) in typical Pinus tabuliformis forest in Qinling Mountains on litter decomposition,nutrient releases (C,N,P,Cu,Zn and Mn) and soil enzyme activities were studied.[Result] The leachates from Taraxacum mongolicum,Corydalis bungeana,Mentha haplocalyx,Houttuynia cordata,Lonicera japonica and Nepeta cataria had significant inhibitory effects on litter decomposition rates and release of nutrients (except L.japonica had no significant effect of N and N.cataria had no significant effect on N and P).The leachates from T.mongolicum,C.bungeana,M.haplocalyx,H.cordata and L.japonica lowered the activity of polyphenol oxidase.The leachates from L.japonica lowered activities of carboxymethyl cellulose,and N.cataria lowered activities of carboxymethyl cellulose and beta-glucosidase.[Conclusion] A.sieboldii,G.pentaphyllum and P.vulgaris were suggested to plant under P.tabuliformis forests,where other 6 species were not suggested as understory species or their inter planting density should be diminished to avoid the inhibitory effects.