The Influence of Plant Water Stress on Net Photosynthesis and Yield of Sunflower (Helianthus annuus L.)

The effect of plant water stress on net photosynthesis, leaf growth, yield and yield-related components were investigated in a single experiment in order to determine in which way water deficits affect sunflower yields.
Sunflower plants, grown under controlled temperature regimes, were stressed during budding, anthesis and seed filling by withholding water until the leaf water potential reached -1600 and -2000 kPa. Leaf area of unstressed plants significantly exceeded that of plants under severe stress during all growth stages investigated. The CO₂ uptake rate per unit leaf area as well as the total uptake rate per plant, significantly diminished with stress, while this effect drastically increased during the reproductive phase of the plant. Although this resulted in significantly smaller heads and kernels, it did not affect the number of seeds borne in the inflorescence. Severe stress during anthesis and seed filling resulted in more empty kernels. Moderate and severe stress during budding significantly lowered both grain and oil yields while plants that experienced moderate stress during anthesis and seed filling significantly outyielded those under severe stress.     

等离子体处理玉米对化肥利用率的影响

2004年在吉林省桦甸市桦郊乡进行了等离子体种子4种不同剂量、6个处理区的试验。经过在拔节期、成熟期干物质的化验分析和测产,结果表明应用等离子体种子处理1.0A×2和1.5A×2的剂量能促进玉米吸收养分,(N P2O5 K2O)总量比CK1提高10%以上;比CK1提高化肥利用率即提高氮肥、磷肥和钾肥利用率为7.4%～8.2%、11.3%～19.7%和15.7%～23.5%。明确了等离子体种子处理1.0A×2的剂量,比CK1增产8.2%,效果显著。     

花生硫素营养特性的研究

对花生的硫素营养特性进行了研究 ,结果表明 :施硫均能显著提高花生各生育阶段对N、S的吸收量 ,提高其N、S含量 ,降低N S比 ,提高花生盛花期以后的N积累比例 ,明显促进S养分向花生籽实部分运转。在不同硫肥品种中 ,以石膏促进花生吸收N、S,提高其N、S含量的效果最好。花生在始花～盛花期吸收硫的强度最大     

棉花品种间苗期钾吸收效率的差异研究

在水培条件下研究了转基因抗虫棉中棉所41和常规棉中棉所36、中棉所35三个品种苗期钾吸收效率的差异及其机制.结果表明,在营养液中钾浓度为0.5 mmol·L-1,可使棉花幼苗生长速率达到最高生长速率80%左右的条件下,中棉所35和中棉所41在6～7叶期的生物量和体内钾吸收量显著高于中棉所36.中棉所35的吸钾量多主要与其根系活跃吸收表面积大有关;中棉所41的吸钾量多可能是相对较大的根系活跃吸收表面积和相对较高的Imax综合作用的结果.中棉所36的Imax虽然显著高于其它两个品种,但体内钾累积量却比较低,这与其较小的根系活跃吸收表面积有关,该品种体内较高的钾浓度也可能对吸收产生反馈抑制作用.在本试验条件下,转基因抗虫棉中棉所41的苗期钾吸收能力与常规棉相比并不低.     

Growth Responses of Twelve Wheat Cultivars and their Phosphorus Utilization from Rock Phosphate

Growth responses of 12 wheat cultivars and their phosphorus utilization were studied in a greenhouse. They were grown for 18 days in a solution containing rock phosphate as the phosphorus (p) source. Biomass of 26 day old plants of all the cultivars varied significantly whereas their shoot to root ratio stayed constant. The dry matter yield of all the 12 cultivars was significantly correlated with the p uptake (r = 0.74). Whereas the higher p uptake by all the cultivars was significantly (P < 0.01) related to the drop in the root medium pH, which was presumably owing to the H⁺ efflux from their roots. The wheat cultivar Blue Silver proved to be the most efficient p user and therefore seems to have the highest potential of making best growth in soils with poor p availability among the 12 wheat cultivars under investigation.     

Effect of varied N rates and N timings on yield, N uptake and fertilizer N use efficiency of a six-row and a two-row winter barley

The effects of N rates and N timings on yield formation, N uptake at five growth stages and fertilizer N use efficiency of six-row and two-row winter barley were evaluated in field trials conducted from 1990/91 to 1992/93 at the TU Munich's research station Roggenstein.

On average over 3 years the six-row cultivar yielded most at a total rate of 110 kg ha⁻¹ N including an early application of 40 kg ha⁻¹ N up to EC 30 (Zadoks scale). The two-row cultivar achieved maximum yield at a total rate of 140 kg ha⁻¹ N including early applications of 70 kg ha⁻¹ N up to EC 30. The highest yielding N-treatments of six-row barley regularly took up less nitrogen at EC 32 (95 kg ha⁻¹ N on average) than the non-optimally fertilized treatments, whereas full exploitation of the yield potential of two-row barley was associated with higher rates of N-uptake at EC 32 (113 kg ha⁻¹ N on average).

Lodging did not occur in the trials conducted in 1991 and 1992 and no difference was detected between the two cultivars in fertilizer N use efficiency. With six-row barley the N treatment giving maximum yield also led to an optimum fertilizer N use efficiency. Full exploitation of the two-row barley yield potential was associated with suboptimal fertilizer N use efficiencies.     

甜菜子叶期幼苗硝态氮吸收特性及其与硝酸还原酶活性的关系

６个有代表性的甜菜品种在人工气候室的营养液培养试验表明，甜菜子叶期幼苗对ＮＯ３＾－的吸收要经最初２ｈ的适应阶段后才可均匀进行。均匀吸收后，观察到多倍体的吸收量〉２倍体，倍性相同品种中Ｅ型〉ＮＥ型〉ＮＺ型〉Ｚ型的初步结果。不同类型品种间ＮＯ３＾－吸收的表观米氏常数（Ｋｍ，ａｐｐ）、最大吸收速率（Ｉｍ）有明显差异，除多倍体ＮＺ型品种甜研３０１的Ｋｍ，ａｐｐ较低而Ｉｍ较高外，其余品种的Ｋｍ，ａｐｐ和Ｉｍ     

等离子体处理玉米对化肥利用率的影响

2004年在吉林省桦甸市桦郊乡进行了等离子体种子4种不同剂量、6个处理区的试验。经过在拔节期、成熟期干物质的化验分析和测产，结果表明应用等离子体种子处理1.0A×2和1.5A×2的剂量能促进玉米吸收养分，（N＋P2O5＋K2O）总量比CK1提高10%以上；比CK1提高化肥利用率即提高氮肥、磷肥和钾肥利用率为7.4%~8.2%、 11.3%~19.7%和 15.7%~23.5%。明确了等离子体种子处理1.0A×2的剂量，比CK1增产8.2%，效果显著。     

包膜尿素不同用量对黄瓜幼苗生长及氮平衡的影响

为确定合理的包膜尿素用量以指导黄瓜育苗施肥,采用生产中常用的草炭:蛭石(2:1)为育苗基质,研究了包膜尿素不同用量对黄瓜幼苗生长、养分吸收及氮平衡的影响。结果表明:包膜尿素用量在125~375 mg N/株的情况下,可协调黄瓜幼苗地上部和地下部的生长,促进幼苗对磷、钾的吸收;移栽时,基质中的氮素残留总量90.5~250.3 mg N/株,其中,残留的包膜氮素占75.4%~82.3%,可实现带肥移栽;育苗期间可产生31.9~121.5 mg N/钵的氮素表观损失。     

氮肥形态及氮钾施用措施对水稻生长 和养分吸收的影响

为探明不同氮（NH4-N和NO3-N）源下，不同施钾水平及氮钾施用次序对水稻生长和养分吸收的影响，进行了温室盆栽试验。结果表明：在水稻生长早期（20d左右时），以NO3-N作为N源时水稻的生物产量和氮钾养分吸收量均显著高于NH4-N作N源的处理，但随着生长时期的延长，NH4-N源更能促进水稻的生长和养分吸收，因此，从整个营养生长时期来讲，铵态氮肥作为水稻N源更具有优越性。结果同时表明，氮肥施用效果与钾肥的施用水平有很大关系，在一般盆栽试验氮肥用量（纯N用量0.15 g/kg）水平下，施钾（K2O）量达到0.51g/kg时会导致水稻的生长及养分吸收量显著下降。铵钾施用次序对水稻的营养生长及养分吸收均有一定的影响，特别是施钾量较高时，铵钾在土壤中的交互作用会导致水稻因氮素供应不足而影响生长和养分吸收。