盆栽和池栽对普通白菜镉累积差异性研究

以不同基因型的普通白菜为试材，研究盆栽和池栽两种栽培方式下土壤中Cd 浓度对普通白菜Cd 累积的影响。结果表明：两种栽培模式下普通白菜的Cd 累积量均随着土壤Cd 浓度的增加而增加，但品种间差异明显；盆栽普通白菜的Cd累积量总体上高于池栽，在土壤Cd 浓度为1.08 mg·kg-1 时盆栽普通白菜Cd 累积量均值为115.08 μg·kg^-1，而池栽仅为64.57μg·kg^-1。     

播期对直播水稻产量、花后各器官干物质和氮素积累及转运的影响

为探究播期对直播水稻产量、花后干物质和氮素积累与转运的影响,以水稻品种白粳1号、长白9号和龙粳31号为供试材料,设置3个播期（SD1、SD2和SD3）,比较不同播期条件下3个品种的产量、抽穗期和成熟期各器官干物质及氮素积累与转运特点。3个品种抽穗期和成熟期各器官干物质及氮素积累量、抽穗至成熟期各器官干物质及氮素转运量和产量均表现为SD2>SD3>SD1。相关分析表明,产量与成熟期穗干物质及氮素积累量呈显著正相关,与叶片干物质和氮素转运量呈显著正相关。在本试验条件下,播期的推迟提高了3个品种有效穗数及结实率,进而提高了产量,同时促进了各器官物质转运量与转运率的提高。各品种SD2处理的产量及花后干物质、氮素积累量最高,SD2为适宜播期。     

三个不同品质类型冬小麦品种籽粒淀粉积累动态及其有关酶的活性变化

在池栽条件下，研究了3个不同品质类型冬小麦品种藁麦8901（强筋）、豫麦49（中筋）和洛麦1号（弱筋）籽粒灌浆过程中淀粉及其组分积累动态和与之有关的酶活性变化。结果表明，3个品种籽粒灌浆过程中支链淀粉的合成均与直链淀粉的合成同时进行，灌浆中后期支链淀粉的合成比直链淀粉的合成快。豫麦49籽粒中直链、支链和总淀粉积累速率均高于其它两品种。3个品种籽粒中腺苷二磷酸葡萄糖焦磷酸化酶（AGPP）、尿苷二磷酸葡萄糖焦磷酸化酶（UGPP）、可溶性淀粉合成酶（SSS）、淀粉粒结合的淀粉合成酶（GBSS）、淀粉分支酶（SBE）活性变化均呈单峰曲线。豫麦49在灌浆期上述各酶活性变化的峰值均高于其他两品种，且大部分酶类在灌浆中后期仍维持较高活性。可见，与藁麦8901和洛麦1号相比，豫麦49具有较强的淀粉合成能力。     

蔬菜对重金属元素的吸收和积累研究进展

就蔬菜对有毒重金属元素的吸收和积累、土壤因子对蔬菜重金属污染的影响等方面的最新研究进展进行了综述,同时对今后的研究方向进行了展望.     

Fruiting position during development of ‘Nules Clementine’ mandarin affects the concentration of K,Mg and Ca in the flavedo

Adequate K, Mg and Ca supply is important to develop well-structured and functional cell walls and membranes in fruit, and insufficient levels or imbalances of these minerals are known to be involved in various postharvest disorders. Microclimatic variation exists in the ‘Nules Clementine’ mandarin tree canopy and results in lower photosynthetically active radiation (PAR) levels and temperature as well as a higher humidity inside the tree canopy. The aim of this experiment was to determine the impact of this variation in microclimate on accumulation patterns of K, Ca and Mg in the flavedo of the fruit rind during stages II and III of fruit development. Fruit mass, dimensions, rind colour development and mineral composition of the flavedo were measured to describe the condition of fruit borne on the outside and inside of the tree's canopy. The data revealed that canopy position influenced mineral nutrient accumulation patterns in the flavedo. Outside fruit flavedo accumulated significantly higher concentrations of Ca and Mg in all three seasons (2005–2007). In contrast, inside fruit flavedo (shaded fruit) accumulated significantly higher levels of K compared with outside fruit flavedo. The accumulation of K and Ca differed from that of kiwifruit and apple in that Ca concentration increased and K decreased towards maturity. These results suggest that xylem, as in citrus leaves, is the main vasculature supply conduit to the citrus fruit flavedo for mineral nutrients. The reduction of transpiration potential by lower temperatures and higher humidity inside the canopy could be responsible for the reduced accumulation of Ca and Mg. The high K concentration of inside fruit flavedo is suggested to be a stress response, due to the low light levels, to maintain osmotic potential in the shaded rind tissue, and this imbalance could possibly lead to a reduction in rind condition, which manifests through rind breakdown symptom development.     

天然次生白桦林凋落物的分解及其生态效应

1988～1990年间以长白山支脉张广才岭帽儿山老爷岭生态站天然次生白桦林为研究对象,对林分凋落物的积累,组成与分解进行了定位观察研究。结果表明,38年生白桦林凋落物的现存量为13.644t/ha,其中叶为10.49t/ha,枝为2.58t/ha,树皮、种实、动物尸体及粪便等仅为0.57t/ha,年凋落盈为3.38t/ha,年分解量为0.633t/ha,年分解率为18.7％。     

连香树人工幼林群落营养元素含量、积累分配和循环

研究了 1 0年生连香树人工群落 8种营养元素的含量、积累分配和循环。主要结论是 :( 1 )连香树营养器官中各种元素的平均含量顺序为Ca>N >Al>K >Mg>P >Fe >Mn。 ( 2 )元素量在各营养器官的分配顺序为根 >叶 >去皮干 >皮 >枝 ,各元素含量顺序为Ca>N >K >Al>Mg>P >Fe >Mn。 ( 3)连香树群落 8种元素的吸收量、存留量和归还量分别是 72 9 82kg·hm- 2 a- 1 、2 0 6 72kg·hm- 2 a- 1 和 52 3 1 0kg·hm- 2 a- 1 。 ( 4) 51 2 %的归还总K量靠降水淋溶归还 ,其余元素总归还量的 55 7%～ 96 5%靠凋落物归还。Fe、Al归还量的 4 1 3%和 4 4 3%通过死根归还。 ( 5) 8种元素的利用系数、归还比和周转期分别为 0 2 3～ 0 54、0 57～ 0 82和 2 2 6～7 63。文中改进了降水淋溶归还的算法 ,提出了群落归还系数、积累系数和吸收系数 ,讨论了落叶树种元素生物循环的算法     

Dry matter accumulation and partitioning in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) as influenced by potassium fertilization

The effect of potassium (K) supply on dry matter accumulation and partitioning of biomass between different among parts of cotton (Gossypium hirsutum L.) was determined under irrigated conditions. The treatments were four cotton cultivars (CIM-448, CIM-1100, Karishma, and S-12), four K rates (0, 62.5, 125, and 250 kg K ha⁻¹), and two K-fertilizer sources (K₂SO₄, KCl). Sequential harvests were collected at four stages of growth, viz first flower, peak flowering, first boll split, and maturity. The dry weights (DW) of vegetative and reproductive organs were determined. Maximum total DW was obtained at 125 days after planting, and then it declined because of leaf senescence at maturity. Cultivars differed significantly among themselves in the production of total DW and its partitioning between different organs. The addition of K fertilizer increased DW substantially at various stages of growth. Potassium fertilizer stimulated cotton plant to translocate resources towards reproductive organs rather than vegetative organs. Crop receiving 250 kg K ha⁻¹ allocated 77% more dry matter into reproductive organs. The K-sources produced a little effect on the allocation of DW in various parts of the plant. Maximum reproductive–vegetative ratio (RVR) was maintained by cv CIM-448 and minimum in cv CIM-1100. Data showed that a shift in DW allocation into reproductive organs was dependent upon sustained supply of K⁺ throughout the season. There were positive significant correlations (0.86, 0.71, and 0.90) between seed cotton yield and total DW, vegetative DW, and reproductive DW, respectively.     

不同浓度钙营养液对烟草矿质营养吸收与积累的影响

本文采用温室水培的方法,研究了不同的钙素供应水平对烟草各种矿质养分的吸收与积累的影响。结果表明,在其它养分形态与浓度一致条件下,随着钙浓度从75mgL-1提高到900mgL-1,烟草生长量呈抛物线型变化。钙浓度为150mgL-1时烟株干物质量最大。超过150mgL-1,随钙的增加而下降,当钙素达900mgL-1(K/Ca为1/6)时,烟株生长严重受抑。随着供钙水平由低到高,烟株氮、磷、钾、锌、锰含量均呈抛物线型变化,含钙量呈直线上升关系,而镁和铜含量则随钙浓度提高而显著下降。烟株各养分积累量均随营养液钙浓度提高呈抛物线型变化,但不同养分出现最大积累量时的营养液钙浓度却不相同。不同供钙水平上烟叶中各元素含量的变化特征与全株的结果基本一致。在低钙浓度范围(75~300mgL-1),钙对钾有协合关系,增钙促进提钾,大于300mgL-1后有拮抗作用,提钙导致降钾。钙与镁、锌、铜、锰间也存在明显的交互作用。烟叶中各元素含量与积累量的变化趋势与整株基本一致。     

Effects of Natural Fallow and Pig Slurry Drip Irrigation on Phosphorus Accumulation and Fractionation in a Coastal Saline Soil

Organic inputs are believed to be able to increase soil phosphorus (P) availability. Natural fallow and pig slurry amendments are the two important organic inputs for agricultural soils. The purposes of the study are to investigate P accumulation and to compare the differences of P fractionation patterns as affected by natural fallow and pig slurry drip irrigation in a coastal saline soil. The study showed that P accumulation occurred mainly in upper soil profiles and that natural fallow or pig slurry drip irrigation alone would not significantly influence total P distribution in soil profiles. However, soil P fractionation demonstrated that, from bottom to top, bioavailable P content and percentage increased whereas residual P percentage declined. The percentage of extractable inorganic P was almost twice as much as that of extractable organic P. In comparison with natural fallow conditions, under pig slurry drip-irrigation conditions, the transformation efficiency of superphosphate fertilizer HCl P_i into residual P was lower whereas the transformation efficiency of superphosphate fertilizer HCl P_i into bioavailable P was higher. The higher bioavailable P percentage and lower average C_org/P ratio in a long-term pig slurry drip-irrigation plot than those in other plots indicated that long-term pig slurry drip-irrigation was more efficient in improving soil P availability than natural fallow and short-term pig slurry drip irrigation.