叶面喷施新鲜人尿对茶叶产量的影响及应用前景

新鲜人尿液作为一种农家有机肥，直接施用于大田是众所周知的，但将其作为一种叶面肥用于催芽肥却鲜为人知，本文记述了喷施人尿对春茶增产效果的田间试验，并对结果作了简要分析；并根据人尿这种天然液肥的特点对其应用前景，特别在有机茶生产上的应用作了讨论。     

儿茶素富集和EGCG单体纯化新工艺研究

EGCG是绿茶中提取分离出的生物活性物质，是一类具有开发前景的天然产物，将绿茶提取物或茶多酚先经乙酸乙酯，氯仿两种试剂多次富集和脱除咖啡因和色素，得儿茶素总含量不低于95％的茶多酚，再经Sephadex LH-20柱层析纯化，得EGCG单体，用ESI－MS和HPLC等方法鉴定和验证了其化学结构，其纯度均大于96．7％，得率为23．86％，回收率为71．25％。     

Effects of slope on soil properties and post construction desertification of highway embankments in an Alpine Meadow region北大核心CSCD

This research investigated effect of slope on the performance of highway embankment soil properties post construction, as there is a demand for technical data of this nature to underpin the design of highway revetment work in alpine meadow regions of China. A section of national road G248 in Northwest Sichuan Alpine Grassland, built 10 years ago, was identified as a study site and plots were marked out for sampling on five slope classes: gentle slope, 6°-15° (GS); moderate slope, 16°-25° (MS); steep slope, 26°-35° (SS); very steep slope, 36°-45° (VS); extreme slope, >45° (ES). Undisturbed flat natural grassland >10 m distant from the roadbed was used as the control (CK). Measurements conducted included determination of particle size composition, physical and chemical parameters of the soils, vegetation cover and the proportion of the plot area exhibiting degradation or desertification. The relative reduction rate of organic matter and total nitrogen was also determined, and differences in soil water content and fertilizer retention capacity were assessed. It was anticipated these data would provide a basis for the construction of ecologically sound slope protection structures in alpine regions. It was found that: 1) Increased slope significantly decreased the proportion of clay and silt particles and increased the proportion of coarse sand and small stones (P<0.05). The greater the slope, the greater the soil bulk density and pH value, and the lower the soil water content. 2) Slope facilitated leaching of soil carbon fractions with the leaching intensity of the fractions ranking soil organic matter (SOM)>total carbon (TC)>inorganic carbon (IC)>dissolved organic carbon (DOC). For example, SOM levels were, respectively, 115, 92, 72, 30, 9 and 3 mg·kg−1 for CK, GS, MS, SS, VS, and ES slope classes while DOC levels ranged from 35.4 mg·kg−1 in CK to 9.2 mg·kg−1 in ES. 3) The ranking for the effects of slope on various soil fertility measures was: effective N>alkali-hydrolysable N>total N>available K> available P>total K>total P. Thus, available N was more easily lost than total N and alkali-hydrolysable N. Available N levels declined progressively across slope classes from 236 mg·kg−1 in CK to 6.3 mg·kg−1 in ES, while total N and alkali-hydrolysable N showed marked loss between GS and VS slope classes. A slope threshold for sharp increase in loss of total P and available P was observed between GS and MS slope classes. With increase in slope gradient, the total K increased, while the available K content decreased. 4) With respect to the influence of slope on the degree of desertification: for CK and GS >90% of the plot area was classed as non-desertified; for GS 79% of the plot area was moderately or severely desertified; for SS, VS and ES, 79, 86 and 94%, respectively, of the plot area was severely or extremely severely desertified. The proportion of severe desertification increased markedly at > 15° slope (i. e. MS) and the proportion of extremely severe desertification increased markedly at >25° slope (i. e. SS). 5) When the slope effects were expressed in relative terms, the relative increase in desertification was high and changed little at slopes >15°, while the relative decreases in organic matter and total nitrogen were high and changed little once slope exceeded 25°. As slope angle increased, relatively low rate of total coverage percentage and powder particles <0.02 mm and the relative increase rate of sand particles >0.05 mm increase significantly. In summary, as slope of the study plots increased, fine sand, silt and clay particles were progressively lost, soil fertility progressively declined, and the degree of desertification increased markedly. Therefore, the technical plan for ecologically sound slope protection in highway construction should be formulated according to the steepness of the slope. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

茶多酚诱导肿瘤细胞凋亡及机理探讨

细胞凋亡的研究不仅对肿瘤的发生和发展的基本理论具有重要意义，而且更会影响肿瘤的防治与治疗，本文综述了茶多酚及其儿茶素诱导肿瘤细胞凋亡的常用研究方法和诱导机理的探讨，以期为茶多酚和儿茶素药效药理的深入研究及其在抗癌药物的研究和开发上提供参考。     

富钾硅多元复合物的生物有效性研究

在氮、磷肥施用的基础上,配施富钾硅多元复合物与施纯硅肥、钾肥、钙镁肥一样,在酸性土壤上具有显著的增产效应;能分别使水稻对该各种元素的总吸收量明显地提高;也能明显地提高水稻对硅、钾、钙、镁吸收,增加植株体内各养分元素的含量。     

土壤沙化度对再生植物群落特征及草地生产能力的影响

【目的】分析土壤沙化度对草地再生植物群落特征及生产能力的影响,为川西北高寒沙化草地的植被修复与重建提供借鉴。【方法】选择植被破坏的4个沙化土地（ND未沙化、LD轻度、MD中度和HD重度）,经4年种子自由迁入与自然竞争生长后,测定再生植被群落结构和优势种特点、功能群草种重要值和产量贡献率等指标。【结果】1）土壤沙化度对再生植物群落特征参数影响为基盖度>投影盖度>群落高度>群落密度>物种数,对优势种种类、种数与高度均有显著影响（P<0.05）。2）土壤沙化度对再生群落中功能群草种重要值及草地生产力有显著影响（P<0.05）,重要值受影响为豆科草类>莎草类>杂类草类>禾草类,产量和贡献率受影响为莎草类>杂类草类>豆科草类>禾草类。LD、MD和HD产量和贡献率最大的分别为禾草类、杂类草类和豆科草类。3）土壤未沙化和轻度沙化草地具有植被自我修复和再生能力,中重度沙化土壤的再生群落结构简单、生产力较低。【结论】川西北高寒草地沙化土地均可形成再生植被,土壤沙化度影响再生植被群落特征和草地生产性能,需依土壤沙化度采取相应的草地复壮...     

酸性水稻土上水稻对硅、钾、钙、镁的吸收及其动力学研究

运用盆栽试验研究了南方稻区酸性水稻土上增施硅(Si)、钾(K)、钙(Ca)、镁(Mg)肥对水稻产量的影响及其水稻对Si、K、Ca、Mg的吸收。结果表明,在酸性水稻土上增施Si、K、Ca、Mg肥及其配合施用均具有显著的增产效益,能明显地提高水稻对该种元素吸收速率和总吸收量。施Si肥主要是增加了水稻后期对Si的吸收,使水稻成熟期能保持较高的Si含量;施用K肥使水稻在移栽后能较长时间内保持较高的K吸收速率;施Ca、Mg肥能使水稻保持较高的Ca吸收速率;K和Ca之间存在不同程度的交互作用。扩散方程、Elovich方程和多项式方程均能很好地描述水稻生长期内水稻对Si、K、Ca、Mg的吸收过程。可用扩散方程和Elovich方程的参数b值来评价水稻对Si、K、Ca、Mg吸收速率。     

富钾硅复合物的农业化学行为研究

富钾硅复合物中硅、钾、钙、镁养分的可溶性含量很高,但其有效态的养分含量却相对较低,故其养分只能缓慢地释放出来。在5个月的贮存过程中,多元复合物的水分含量对其养分的有效性没有明显的影响,但其养分含量却经历了一个明显的变化过程,其中可以用Freundlich方程拟合钾、镁的变化规律。多元复合物中硅、钾、钙、镁4种养分元素的释放速率随时间的延长而逐渐下降。     

寒区公路不同坡度护坡土壤性状和群落特征及功能群差异

通过对G248公路高寒草原区红原县机场段的4个坡度（缓坡6°～15°、斜坡16°～25°、陡坡26°～35°、急坡36°～45°）护坡，进行土壤颗粒组成和理化指标、植被群落结构和优势种、功能群草种重要值等指标测定，研究坡度对物种种类、多样性、丰富度、均匀度及功能群重要值的影响。结果表明：坡度增加使土壤砂粒比例增大而粘粒和粉粒比例降低（P<0.05），含水量与有机质及有效N、P、K含量下降（P<0.05），使土壤易退化与沙化。坡度显著影响物种数、物种多样性、物种丰富度和物种均匀度和优势种种类、高度、比例及功能群植物的重要值（P<0.05），坡度越大群落密度、投影盖度和基盖度越低。故生态护坡建设应注意坡度对土壤沙化、植物种类及群落特征的影响。