棉花离体不定根系的发生对色素腺体密度和棉酚含量的影响

为探明根系对色素腺体密度和棉酚含量的影响，以离体条件下的无根幼苗、不同生根状态幼苗以及无菌种子苗作为研究对象，对其茎叶色素腺体密度、棉酚含量以及棉酚生物合成关键基因表达量进行分析。结果表明，不同生根状态幼苗中，色素腺体密度和棉酚含量与一定范围内生根数呈显著正相关，随后趋于平稳。荧光定量PCR显示，棉酚生物合成关键基因GhCDN1和GhWRKY1表达量在生根数多的无菌苗中显著增高，而对棉酚合成具有反馈调节作用的 GhCYP706B1表达量呈现相反趋势；无根幼苗茎叶腺体密度和棉酚含量均显著低于有根幼苗，棉酚生物合成关键基因GhCDN1、GhWRKY1和 GhCYP706B1表达量反而高于有根幼苗。有根幼苗中根的棉酚含量显著高于茎和叶，无菌种子苗根系中棉酚生物合成关键基因表达量显著高于茎和叶。说明棉花根系能对棉酚含量产生直接影响，同时影响腺体密度。本研究进一步验证了根系是棉酚主要合成部位，地上部分也存在少量的棉酚合成，只是不能引起棉酚发生显著变化。     

丘陵红黄壤区施用399对“一种两收”再生稻根系和产量的影响

[目的]研究399对"一种两收"再生稻的影响。[方法]以适宜丘陵红黄壤种植的丰两优香1号、准两优527、宜优673再生稻品种为材料,分别设置喷施399和不喷施399(CK)2种处理,研究各处理对再生稻根系和产量的影响。[结果]结果表明:施用399使水稻在生育期上延缓成熟,且施后再生稻的总根系数量、白根数量、根鲜重、根干重、根体积大幅度增加,同时在两季总产量上准两优527、丰两优香1号和宜优673品种分别比对照增产6.39%、4.86%、5.94%。[结论]施用399有利于准两优527、丰两优香1号和宜优673再生稻品种再生根的发生。     

水稻根系育种研究进展

水稻（Oryza sativa L.）根系对水稻的生长发育及产量形成具有至关重要的作用。根据目前水稻根系育种的研究现状，分析了水稻根系育种对提高产量、改变形态特征和生理特性的重要性，并对其研究前景进行了分析和展望。     

Organic input quality is more important than its quantity: C turnover coefficients in different cropping systems

Annual C input to soil is a major factor affecting soil organic carbon (SOC) dynamics. However different types of C-sources can have different behaviour, in relation to their chemical characteristics and how they interact with soil. Root-derived C, in particular, should be more efficient than other organic materials as a result of the physicochemical and biological characteristics of the surrounding environment, leading to a reduction in the C decomposition rate.To test this hypothesis, we considered a long-term experiment underway in Northern Italy since 1962, comparing permanent meadow and 6 different crop rotations over a wide range of nutrient inputs, in both organic and inorganic forms. C inputs from amendments were measured and those from crops were calculated using allometric functions and crop and residues yields. The time evolution of SOC was studied through a single-pool, first-order kinetic model, allowing the estimation of humification coefficients for residues, roots, farmyard manure and cattle slurries.The highest value of the humification coefficient was estimated for farmyard manure, which confirmed its high efficiency in stabilising SOC content. Root C presented a humification coefficient 1.9 times higher than above-ground plant materials while slurries were intermediate, with a humification coefficient roughly half that of farmyard manure and even lower that of roots.The quality of C input thus seems of fundamental importance for evaluating the sustainability of different cropping systems in terms of SOC dynamics.     

Above- and belowground biomass measurements in an unthinned stand of Sitka spruce (<Emphasis Type="Italic">Picea sitchensis</Emphasis> (Bong) Carr.)

Reporting carbon (C) stocks in tree biomass (above- and belowground) to the United Nations Framework Convention on Climate Change (UNFCCC) should be transparent and verifiable. The development of nationally specific data is considered ‘good practice’ to assist in meeting these reporting requirements. From this study, biomass functions were developed for estimating above- and belowground C stock in a 19-year-old stand of Sitka spruce (Picea sitchensis (Bong) Carr.). Our estimates were then tested against current default values used for reporting in Ireland and literature equations. Ten trees were destructively sampled to develop aboveground and tree component biomass equations. The roots were excavated and a root:shoot (R) ratio developed to estimate belowground biomass. Application of the total aboveground biomass function yielded a C stock estimate for the stand of 74 tonnes C ha⁻¹, with an uncertainty of 7%. The R ratio was determined to be 0.23, with an uncertainty of 10%. The C stock estimate of the belowground biomass component was then calculated to be 17 tonnes C ha⁻¹, with an uncertainty of 12%. The equivalent C stock estimate from the biomass expansion factor (BEF) method, applying Ireland’s currently reported default values for BEF (inclusive of belowground biomass), wood density and C concentration and methods for estimating volume, was found to be 60 tonnes C ha⁻¹, with an uncertainty of 26%. We found that volume tables, currently used for determining merchantable timber volume in Irish forestry conditions, underestimated volume since they did not extend to the yield of the forest under investigation. Mean stock values for belowground biomass compared well with that generated using published models.     

沙棘根系模糊聚类及生长分布规律的探讨

本文对黄土残塬沟壑区人工沙棘林单株根系进行了系统研究。结果表明:1.主根龄是影响沙棘单株根系间模糊聚类的决定性因素,幼龄期单株根系间极易聚合,随着主根龄增加,同龄单株根系间差异逐渐加大而较难聚合。2.用灰色Verhoulst模型对单株沙棘根量、根长的变化过程进行描述和预测,当主根龄达到17龄左右时,根系基本停止生长。3.沙棘根量、根长在土体中的垂直分布规律呈双曲函数关系,各实测值与计算值拟合非常贴切。4.沙棘根系密集层随主根龄的增加而加深,最终稳定在0-50cm左右,粗壮根系多集中在该层。文中还建立了沙棘根量与叶量的线性回归方程。     

Earthworm channels in cultivated clayey and loamy Norwegian soils

Studies of earthworm species and their activity, expressed as channels, on cultivated loamy (Humic Cryaquept) and clayey soils (Typic Endoaqualf and Typic Cryaquept) were conducted in southern and central Norway before conversion from conventional to organic cropping systems. At all the three study areas: Landvik (Grimstad), Voll (Ås) and Kvithamar (Stjørdal), the earthworm species Aporrectodea caliginosa, Aporrectodea rosea, Allolobophora chlorotica and Lumbricus rubellus were found. At Landvik, where the deep-burrowing species Aporrectodea longa, A. caliginosa and Lumbricus terrestris dominated, medium (4–6 mm) and coarse (>6 mm) earthworm channels were most numerous below the plough layer. Almost no coarse pores were found at Voll and Kvithamar. The volume of earthworm channels below the plough layer was 0.6–0.8% of total soil volume at Landvik and Voll and 0.3–0.4% at Kvithamar. Earthworm channels >6 mm below the plough layer were useful to identify present and previous activity of deep-burrowing earthworms such as L. terrestris. Below the plough layer, roots were almost entirely restricted to earthworm channels and interaggregate spaces.     

不同早稻品种灌浆期高温胁迫后根系生理差异研究

试验研究不同早稻品种灌浆期高温胁迫后根系生理差异结果表明,高温对不同水稻品种根系超氧化物歧化酶、过氧化物酶、过氧化氢酶活性均有影响,但对耐热型品种的影响显著小于热敏感品种,耐热型品种在高温胁迫后保护酶活性能较快恢复并接近对照水平;高温胁迫对耐热型水稻品种根系α-萘胺氧化力无影响,但热敏感品种根系氧化力明显下降,故根系α-萘胺氧化力可作为根系耐热指标之一。     

大叶速生槐种根育苗技术研究

[目的]提高大叶速生槐种根的繁殖系数和苗木的质量。[方法]对不同直径不同长度的大叶速生槐种根的繁殖方法进行研究。[结果]直径5 mm以上的种苗种根采用直接栽种的方法,直径3～5 mm的种根采用先育苗再移栽的方法,育苗主要采用沙坑密植、营养袋育苗和塑管育苗等方法。[结论]此法不仅提高了大叶速生槐种根的繁殖系数,而且提高了苗木的质量。     

调节剂浸种对马铃薯不同芽位母薯生理代谢及根系形态的调控效应

[目的]通过比较不同芽位马铃薯母薯生理代谢及根系形态的变化,分析了植物生长调节剂对马铃薯生长的调控效应。[方法]采用盆栽试验,浸种使用不同植物生长调节剂,研究母薯生理代谢及根系理化性状变化,探讨植物生长调节剂对马铃薯生育进程的影响。[结果]DTA-6可以提高顶部芽位母薯播后21 d内还原糖含量,对播后42～56 d根系长度、根系体积及根系干重均有提高的调控效应;DTA-6可以提高基部芽位母薯播后7～28 d内可溶性糖含量,但减少播后42～49 d根系干物质积累。SODM对顶部芽位母薯的调控效应与DTA-6基本相同,但是它对可溶性糖含量提高的效果好于DTA-6。就基部芽位母薯而言,SODM可以提高播后7～28 d内可溶性糖含量,降低播后42～49 d内根系干物质的积累,但调控效应较弱。[结论]植物生长调节剂能够通过调控马铃薯母薯生理代谢及根系形态的变化进而影响马铃薯生长发育进程。