脱落酸、吲哚乙酸和乙烯在猕猴桃果实后熟软化进程中的变化

 果实采后初期，ABA含量积累增加，早鲜和海沃特两品种分别于采后第3d和第4d达到最高值，随后迅速下降；后熟进程中，两品种的内源IAA水平均急速下降，并伴随出现乙烯跃变，两品种分别于采后第8d和第14d出现乙烯峰值；采后果实硬度急剧下降，两品种分别于第9d和第14d降至1.0kg/cm#+2以下；外源ABA处理可促进采后果实的乙烯生成，并加速乙烯跃变峰的到来和果实的软化；CaCl#-2采后浸果显著抑制了内源ABA合成增加，并延缓了果实后熟软化过程。ABA可能在猕猴桃果实软化进程中起着更重要的作用。     

湿冷贮藏对冬枣软化水解酶活性影响的研究

软化是冬枣贮藏中存在的主要问题之一。研究了湿冷贮藏对冬枣不溶性果胶含量和果胶甲酯酶(PM E)活性、可溶性果胶含量和多聚半乳糖醛酸酶(PG)活性、纤维素含量和纤维素酶(Cx-cellulases)活性、淀粉含量和淀粉酶活性的影响。结果表明,湿冷贮藏可以延缓冬枣不溶性果胶含量、淀粉含量和PG活性的下降速度,降低可溶性果胶含量、PM E活性、Cx-cellulases活性、淀粉酶活性的上升速度,而纤维素含量则表现为先慢后快的增长规律。     

木材软化技术的初步研究

初步研究了两种木材的化学软化技术，通过试验确定了软化剂、软化处理方法。对软化材的化学成分测定和弯曲稳定性的检测结果表明，化学软化剂的配方合理，效果明显，价格便宜，其处理方法简单易行。     

果实软化过程中细胞壁结构和组分及细胞壁酶的变化

概述了果实软化过程中细胞壁结构和组分及细胞壁酶的变化。多数果实软化是由于多聚半乳糖醛酸酶、纤维素酶、果胶甲酯酶和β-半乳糖苷酶等细胞壁酶降解细胞壁物质,使细胞壁结构和组分发生变化,进而引起果实软化。不同的研究结果提示果实软化也有其他因子参与,加强果实生理生化基础研究尤为重要。     

水热-微波处理对榆木软化和顺纹压缩及弯曲的影响

采用水热-微波处理方法对榆木成熟材进行软化处理,通过顺纹压缩率、单维和多维弯曲最小曲率半径表征木材软化效果;以XRD,FYIR等方法测定木材表面组成、结晶度变化,分析软化处理对木材顺纹压缩的影响.结果表明:水热-微波处理可显著增强木材的软化性能,处理后木材中的抽提物几乎完全抽出(1.73%～0.47%),半纤维素发生明显降解,使木质素相对含量得到增加,木材表面羟基数量显著增加;非结晶区微纤丝趋于有序,相对结晶度提高,结晶区表面微纤丝羟基裸露,氢键键合增强,结晶区宽度增加.当采用处理方案为B时,顺纹压缩率最大,单维和多维弯曲时的曲率半径最小.较高的结晶度和适宜的羟基数量是试样B表现出较高软化性能的主要原因.     

杉木刨切试验研究

在对杉木节子进行水热软化试验和硬度测试基础上，对用杉木小径材制作的140mm×140mm×2000mm木方进行了刨切试验。结果表明：由于杉木节子多、硬度大，刨切前必须进行充分的水热软化处理，同时加大刨刀的楔角。建议刨刀楔角采用22°，当刨切厚度为1-2mm时水热处理的时间为28天；刨切厚度为3-4mm时水热处理时间为42天。     

Analysis on key problems of initiative decompression pre-reinforced structure

In slope engineering, the shear resistance of rock and soil can never be exerted themselves by general pre-reinforced structure, through the coupling mechanism between reinforced structure and slope, an initiative decompression pre-reinforced structure consists of soft stuffing and pre-reinforced structure is presented. The setting and thickness of soft stuffing are both key questions during the design of initiative decompression pre-reinforced structure. On one hand, the setting of soft stuffing assure that parts of initiative decompression pre-reinforced structure cannot interact each other under reinforcing; on the other hand, the thickness of soft stuffing can assure that the shear resistance of rock and soil can be exerted by themselves, the sliding thrust which is endured by pre-reinforced structure alone is changed to be endured by soil and pre-reinforced structure together. Then the sliding thrust endured by pre-reinforced structure minimizes, accordingly the effect of initiative decompression is achieved. In the end, the calculation procedure of thickness is illustrated by a practical project and the result is rational.     

Preharvest calcium applications inhibit some cell wall-modifying enzyme activities and delay cell wall disassembly at commercial harvest of ‘Fuji Kiku-8′ apples

To improve apple firmness during the postharvest chain, detailed knowledge of the biochemistry underlying ripening-related cell wall disassembly, a very complex event, is required. Apple softening is reportedly mediated by calcium loss from the middle lamella, and accordingly calcium applications are expected to preserve fruit firmness. In this work, pre-harvest calcium sprays (7 weekly applications at 1.6%, w/v, 81-123 days after full bloom) were applied to ‘Fuji Kiku-8′ apples, with the purpose of examining treatment effects on cell wall metabolism during on-tree fruit maturation and ripening. Applied calcium improved cell-to-cell adhesion as indicated by better preservation of the middle lamella and by higher contents of ionically bound pectins in treated fruit, leading to higher fruit firmness levels at commercial harvest. Matrix glycan breakdown was also delayed in response to calcium treatment. Calcium applications partially suppressed pectinmethylesterase, pectate lyase, β-galactosidase, α-l-arabinofuranosidase and β-xylosidase activities, without any apparent relationship with ethylene production rates.     

中国木材改性研究最近十年进展

随着国家天然林保护工程的实施，人工林木材的大量利用已成为解决木材供需矛盾的重要途径，对一些材质较差的人工林木材的改性也成为迫切需要解决的重点课题。概述了我国木材科学界在木材颜色处理、软化处理、尺寸稳定化处理、强化处理以及阻燃处理等方面最近10年的研究成果，并提出了发展方向，为木材改性的进一步研究提供参考。