Foliar feeding of boron improves the productivity of cotton cultivars with enhanced boll retention percentage

Abstract

Cotton (Gossypium hirsutum L.) is of prime importance because of its quality fiber and edible oil production. Boron (B) is among essential micronutrients for plant growth; it aids in the transfer of sugars and nutrients from leaves to fruit that are involved directly or indirectly in many plant functions. Cotton growth, yield and quality are strongly affected with boron application. A two-year study was conducted to evaluate the impact of foliar applied B (0, 2, 4, 6, 8 and 10?g of B L^?1 of water) on the performance of cotton cultivars (FH-113, MNH-786 and CIM-496). The results indicated that growth, yield and quality traits of cotton were significantly influenced by different levels of foliar applied boron as well as cultivars of cotton. Among cotton cultivars, the yield and quality parameters were superior in cultivar “FH-113.” Foliar application of boron at 6?g L^?1 of water improved leaf area index and leaf area duration and eventually improved the number of bolls per plant, boll retention percentage, average boll weight, lint yield, ginning out turn, fiber length and uniformity ratio of cotton. Foliar application of B at 6?g per liter of water, showed promising results by improving growth and quality parameters and is recommend to enhance the economical yield production of cotton cultivar “FH-113” with improved quality.     

基于多种光谱仪的水稻前期植株氮积累量监测

为了明确水稻穗肥施用前地上部植株氮积累量与各光谱仪冠层光谱参数的定量关系,进而为水稻精确追氮提供决策依据。基于不同品种和不同施氮水平的7个水稻田间试验,于分蘖期和拔节期利用ASD Fieldspec FR2500高光谱仪、Cropscan MSR-16多光谱仪和Greenseeker RT100主动光谱仪同时采集冠层光谱反射率,并同步取样测定地上部植株氮积累量,研究基于不同光谱仪构建的植被指数与植株氮积累量之间的关系。结果表明,部分植被指数与水稻地上部植株氮积累量关系密切,基于3种光谱仪构建的水稻地上部植株氮积累量监测模型的稳定性和适用性有较大差异。对于ASD高光谱仪,虽然基于差值植被指数（760,740）能较好估测植株氮积累量,拟合模型决定系数R2为0.79,但模型检验效果较差,其R2和均方根误差分别为0.15和2.11 g/m2;对于Cropscan多光谱仪,差值植被指数（760,710）能较好反演植株氮积累量,拟合模型的R2为0.94,模型检验的R2和均方根误差分别为0.94和0.76 g/m2;Greenseeker主动光谱仪的归一化植被指数（770,660）对地上部植株氮积累量的反演效果最好,拟合模型的R2为0.97,模型检验的R2和均方根误差分别为0.97和0.62 g/m2。研究结果可为水稻前期植株氮积累量监测过程中的光谱仪选择提供参考,为水稻精确追氮管理提供技术支撑。     

番茄不同生育期遮荫对其干物质分布、产量及叶片养分含量的影响

Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects of three shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N),phosphorus (P) and potassium (K) in leaves and yield at three growth stages (early flowering (EF), peak flowering (PF) and later flowering (LF)). Shading reduced the dry weight of root and stem tissues at the EF and PF stages, but the 40% shading increased root dry weight and stem dry weight by 43.2% and 21.6%,respectively, at the LF stage. The influence of shading on the dry weight of leaves was very small at most growth stages. Shading had no effects on total leaf N, P and K contents at the EF and PF stages, showing that N, P and K absorption were regulated by the carbon assimilation at these two stages. The leaf N, Pand K contents of 40% shaded plants at the LF stage were significantly increased. There were no obvious differences in leaf N and K contents between 75% and 40% shading treatments, but significant difference in leaf P contents was found between them at the LF stage. Shading significantly enhanced the friit yield of 40% shaded tomato plants at the LF stage, but failed to affect the fruit yield of shaded plants at the EF stage. These showed that tomato could grow well and a better yield could be obtained if some moderate shading (i.e., 40% shading) was applied at the LF stage at s, mmer midday.     

Interaction of Zinc and Phosphorus in relation to micronutrient nutrition of rice plant at two different growth stages

A greenhouse pot experiment was conducted to study the effect of application of three levels of phosphorus (0, 50 and 100 ppm) and three levels of zinc (0, 5 and 10 ppm) in all possible combinations on yield and tissue concentrations of zinc, copper, iron and manganese by rice at two different growth stages (35 and 90 days after transplantation). The results showed that application of both phosphorus and zinc increased the dry matter yield of shoot and root at both the growth stages. Phosphorus or zinc application was found to influence the concentration of zinc, copper, iron and manganese in shoot and in root but these influences varied with the growth stages of the plant as well as with the level of zinc and phosphorus application. The results further showed that phosphorus or zinc application influenced the absorption of zinc/phosphorus, iron, manganese and copper by rice plants and their translocation from root to shoot. Such effects were found to be more prominent at early growth stage than at late growth stage of the plants.     

玉米不同生育期茎秆流特征及其模型构建

为系统测定玉米不同生长阶段在不同降雨强度下的茎秆流量并建立简易实用模型,该研究以单株玉米（Zea mays）为对象,采用室内人工模拟降雨的方法,系统测定不同降雨强度、不同测试阶段玉米植株的茎秆流量,分析了玉米茎秆流与叶面积和降雨强度的关系,并在此基础上进行了单株玉米茎秆流模型构建的研究。结果表明：玉米在其全生育期内,茎秆流量占冠层上方降雨的44.55%;茎秆流量随叶面积、降雨强度增大呈现增加趋势,茎秆流率随叶面积增大呈增加趋势但是随降雨强度的变化不显著。通过分析其关系,构建了单株玉米茎秆流的理论模型、半经验模型和经验模型。经试验验证,3个模型都适用于估算玉米不同生长阶段的茎秆流量及茎秆流率,且达到预期的精度要求,并认为单株玉米的半经验模型在实际测量与应用中更为简便精确。该研究提出的玉米茎秆流模型可为研究玉米冠层对降雨及喷灌水分的空间分异、土壤水分运移及土壤侵蚀研究提供了计算方法,同时为玉米大田灌溉的水量平衡及水肥管理提供指导。     

Mineral composition of field grown winter wheat inoculated with phosphorus solubilizing bacteria at different plant growth stages

A two year field experiment was conducted in field conditions using wheat (Triticum aestivum ssp. vulgare L. cv. Bezostaja) as the test plant for the evaluation of phosphate solubilizing (+PS) microorganisms. Bacterial strains significantly (P < 0.05) increased plant biomass (by 13 to 36%) without plant P enrichment. Only Bacillus sp. #189 significantly (P < 0.05) raised plant P-content, biomass and rhizosphere soil Olsen P at Zadoks Scale 62 simultaneously. Inoculations variably increased plant potassium (K-), magnesium (Mg-), zinc (Zn-), and managenese (Mn-) contents at harvest (Zadoks 92) but not earlier (Zadoks 31 and 61). The enrichment of the inoculated plants with nutrients other than P indicates the presence of alternative plant growth promoting mechanisms. This study showed that promising phosphate solubilizing microorganisms could increase not only the P content of the plants, but also the soil available P in rhizosphere transiently.     

The difference in the formation of thermotolerance of two cotton cultivars with different heat tolerance

ABSTRACT

In order to study the mechanism of thermotolerance of cotton cultivars with different heat tolerance, the response of yield component and photosynthesis to short-term heat stress (HT; average temperature 34°C) was studied. Pot experiments were carried out in 2015 and 2016 by using cotton cultivar PHY370WR (heat tolerant cultivar) and Sumian15 (heat susceptible cultivar). Results showed that heat (34°C) treatment resulted in a significant (p < 0.05) reduction in cotton yield. Path analysis showed that the direct path coefficient (0.89) of boll weight was higher, compared with the boll number (0.46). With high-temperature stress, it was the difference of boll weight reduction contributed the majority to the difference of yield reduction between cultivars, not the difference of boll number reduction. Different decrease in photosynthesis between cultivars leads to the different decline in boll weight. Different thermotolerance between the two cultivars were as follows: the heat tolerant cultivar could maintain higher photosynthesis rate under HT, and it could recover more quickly and highly in photosynthesis than the heat susceptible cultivar. More importantly, the leaf functional period of heat tolerant cultivar was less shortened by HT than that of heat susceptible cultivar.     

不同碳氮比猪粪堆肥及其产品肥效

为有效处理规模化猪场养殖粪污,确立猪粪堆肥的原辅料最佳配比,建立高效堆肥工艺。通过工厂化堆肥试验,以猪粪为原料,稻壳和蘑菇渣为辅料,设置3个C/N分别为10、25和35的处理(Z1、Z2、Z3),比较不同碳氮比猪粪、稻壳及蘑菇渣混合物高温堆肥过程中堆体温度、pH值、EC、C/N、养分等指标差异和黄瓜盆栽促生试验中不同处理所得猪粪堆肥的促生效果。3个处理的高温期平均温度为Z2Z3Z1,堆肥结束时各处理的pH值为7.51、7.63、6.96,EC值为1.31、1.65、1.54 m S·cm-1;NH_4~+-N的含量为Z3Z2Z1;NO-3-N含量为Z1=Z2Z3,各处理C/N分别下降了18.24%、47.56%、30.47%,Z1、Z2、Z3的氮、磷、钾(N、P_2O_5、K_2O)总养分含量分别达50.25、51.66、48.43 mg·kg-1。3个堆体的发芽指数显示其均已腐熟,三维荧光图谱则显示Z1、Z2腐熟程度较高于Z3。两季盆栽促生试验结果显示化肥处理与Z2处理肥效最佳,Z1、CK处理次之,Z3处理效果最差。C/N为25是堆肥适宜的C/N初始设定值,有利于堆体的快速腐熟和养分保持,其堆肥产品肥效优异。     

增硝营养对水稻不同生育时期生长及氮素吸收同化的影响

The effect of nitrate （NO3^-） on rice （Oryza sativa L.） growth as well as N absorption and assimilation during different growth stages was examined using three typical rice cultivars. Dry weight, yield, N uptake, nitrate reductase activity （NRA） in leaves, and glutamine synthetase activity （GSA） in roots and leaves during their entire growth periods, as well as the kinetic parameters of ammonium （NH4^＋） uptake at the seedling stage, were measured with solution culture experiments. Results indicated that addition of NH4^＋-N and NO3^-N at a ratio of 75：25 （NH4^＋＋NO3^- treatment） when compared with that of NH4^＋-N alone （NH4^＋ treatment） increased the dry weight of ‘Nanguang＇ cultivar by 30% and ‘Yunjing 38＇ cultivar by 31%, and also increased their grain yield by 21% and 17%, respectively. For the four growth stages, the total N accumulation in plants increased by an average of 36% for ‘Nanguang＇ and 31% for ‘Yunjing 38＇, whereas the increasing effect of NO3^- in the ‘4007＇ cultivar was only found at the seedling stage, in the NH4^＋＋NO3^- treatment compared to the NH4^＋ treatment, NRA in the leaves increased by 2.09 folds, and GSA increased by 92% in the roots and 52% in the leaves of the three cultivars. NO3^- supply increased the maximum uptake rate （Vmax） in the ‘Nanguang＇ and ‘Yunjing 38＇ cultivars, reflecting that the NO3^- itself, not the increasing N concentration, increased the uptake rate of NH4^＋ by rice. There was no effect on the apparent Michaelis-Menten constant （Kin） of the three cultivars. Thus, some replacement of NH4^＋ with NO3^-could greatly improve the growth of rice plants, mainly on account of the increased uptake of NH4^＋ promoted by NO3^-, and future studies should focus on the molecular mechanism of the increased uptake of NH4^＋ by NO3^-.     

不同生育期烤烟根系固土能力特征研究

本研究选取云南省主要种植作物——烤烟为试验材料,分析烤烟不同生育期(团棵期、现蕾期、成熟期)的根系固土能力特征。应用锚杆拉力计和自行设计的剪切箱对不同生育期烤烟根系的固土能力在0~10 cm和0~20 cm土层进行原位测定。结果表明:同一生育期,根系密度表现为0~10 cm0~20 cm;同一土壤深度范围内,根系密度表现为成熟期现蕾期团棵期。相同深度范围内,固土能力表现为成熟期现蕾期团棵期;在现蕾期和成熟期,固土能力表现为0~10 cm0~20 cm,而团棵期由于根系尚未深扎至20 cm深度,只有在样方的塑性变形阶段的固土能力,表现为0~10 cm0~20 cm;同一生育期相同深度范围内,载荷与位移间呈现显著的直线相关关系(P0.01)。随着载荷的增加,将出现载荷临界点F1、F2和F3,F1为比例极限点,F2为屈服拉力点,F3为抗拉极限点。相同深度,F1与根系密度间无明显相关关系,F2和F3分别与根系密度间呈显著幂函数关系。在0~10 cm,F2与根系密度和F3与根系密度的相关方程分别为y=1.313x0.042和y=1.379x0.084;在0~20 cm,F2与根系密度和F3与根系密度的相关方程分别为y=1.389x0.048和y=1.638x0.077。该测定方法可以在水土保持上作为评价不同作物(植物)固土能力的有效参考手段,建立不同作物根系固土数据库,为坡耕地作物配置提供理论依据。     

玉米不同生育阶段养分效应评价方法研究

了解作物养分效应机制是提高作物养分利用效率的重要基础。本文以玉米品种"农华101"为试验材料, 进行不同播期、密度、肥料试验, 记录了生育时期的日均温, 并对玉米不同生育时期叶片及其他器官中氮、磷、钾元素含量进行了测定, 然后基于改进后的BLUP方法, 在考虑植株干物质日均积累量与自身效应、环境效应关系的基础上, 引入群体效应和温度效应, 探讨并建立了玉米不同生育阶段养分效应评价方法。在此基础上, 进一步对养分效应评价效果进行分析。结果表明: 干物质日均积累量理论值与实际值的相关性r值为0.72~0.99; 各生育阶段配对t检验的α值均大于0.05, 各生育阶段的干物质日均积累量的理论值和实测值差异均不显著(P>0.05)。研究结果表明, 用建立的玉米不同生育阶段的养分效应评价方法得到的各养分特征效应值存在较大差异, 其中: 三叶期到拔节期各养分效应值为0~0.58, 拔节期到大口期为 0.43~2.57, 大口期到吐丝期为 0.45~4.58, 吐丝期到成熟期为 0.86~4.71。综上, 利用改进后的BLUP法提出的养分效应评价方法对玉米各阶段养分效应的评价结果具有一定的指导意义, 该方法可作为玉米养分效应评价的参考手段。     

Nutrient content of Kenaf (Hibiscus cannabinus) at five growth stages

Abstract

Kenaf (Hibiscus cannabinus) grown during the wet season in the Ord Irrigation Area of Western Australia was sampled at five growth stages. The samples were separated into bark, wood, tops plus foliage and, where applicable, seed. Each fraction was analysed for zinc, manganese, iron, copper, sodium, potassium, calcium and magnesium by atomic absorption spectroscopy, and for nitrogen and phosphorus by colorimetry. Concentrations of these elements in each plant fraction are presented. Calculation of total above‐ground nutrient content of the crop indicated a high content of potassium throughout the growth cycle (up to .280 kg/ha), an initially high content of nitrogen (150 kg/ha) stabilising at a lower level (about 75 kg/ha) up to maturity, and an increasing content of zinc (150 g/ha to 350 g/ha) and calcium (65 kg/ha to 105 kg/ha) with age. A higher content of iron at maturity was also apparent (up to 1400 g/ha). A comparison with other reported data is made.     

Foliar application of silicon at different growth stages alters growth and yield of selected wheat cultivars

To evaluate the response of some selected wheat cultivars to silicon application at different growth stages under drought stress, an experiment was carried out in the greenhouse of College of Agriculture, Shiraz University, Iran, during 2012 using a completely randomized factorial design with four replications. Experimental treatments included drought stress (100% F.C. as control and 40% F.C. as drought) and foliar application of 6 mM sodium silicate (control, application at mid tillering stage, at anthesis stage, and application at tillering + anthesis stages) and wheat cultivars (Sirvan and Chamran, relatively drought-tolerant, and Shiraz and Marvdasht, drought-sensitive cultivars). Drought stress significantly reduced chlorophyll content, leaf area, relative water content, grains per spike, 1000-grain weight, grain yield and biomass of all wheat cultivars. Furthermore, drought stress increased electrolyte leakage of the flag leaves of all cultivars. In contrast, foliar-applied silicon significantly increased these parameters and reduced electrolyte leakage. Furthermore, highest positive influence of silicon application was observed at combined use of silicon both at the tillering + anthesis stages in wheat plants under both stress and non-stress conditions. Significant differences were found in physiological responses among wheat cultivars. The drought tolerant cultivars (Sirvan and Chamran) had significantly higher growth and yield than those of drought sensitive cvs. Shiraz and Marvdasht under drought stress. In conclusion, foliar application of silicon especially at the tillering + anthesis stages was very effective in promoting resistance in wheat plants to drought conditions by maintaining cellular membrane integrity and relative water content, and increasing chlorophyll content.     

Mycorrhizal inoculation enhances growth and nutrition of cotton plant

Arbuscular Mycorrhizae Fungi (AMF) inoculations may improve growth and nutrient uptake of cotton (Gossypium hirsutum L.) plant. Although the importance of mycorrhizal symbioses for growth and nutrient acquisition of cotton plant is known, less is known about mycorrhizal dependency on P and Zn nutrition under low Zn fertile soil conditions. A greenhouse experiment was conducted to investigate the effect of different of P and Zn fertilizer addition on cotton plant growth as well as Zn and P uptake. Sterilized and non-sterilized low Zn fertile Konya series soil was treated with different levels of P and Zn. Soils were inoculated with two mycorrhizae species like Funneliformis mosseae and Claroideoglomus etunicatum after sterilization. Results showed that mycorrhizal inoculation on plant growth and nutrient uptake has significant effect when soil was sterilized. Cl. etunicatum mycorrhizae species has greater effect than Fu. mosseae mycorrhizae species. Root colonization increased 23–65% due to mycorrhizal amendment. The shoot: root ratio increased by 13 and 22% for non-sterile and sterile condition respectively in mycorrhiza amended soil. Mycorrhizal dependency varies 1–55% and 3–64% for non-sterile and sterile soil respectively on mycorrhizae, P and Zn amended soil. Mycorrhizal dependency analysis showed that cotton plant in both sterile and non-sterile soil conditions depends on mycorrhizae species, P nutrition, however is less depend on Zn nutrition. This study concluded that the inoculation of cotton plant with selected mycorrhizae is necessary under both sterile and non-sterile soil conditions.     

不同生育期苹果园土壤氨氧化微生物丰度研究

【目的】大量施氮引起的土壤酸化问题已严重制约苹果的安全生产。氨氧化微生物驱动的土壤硝化作用是土壤氮素循环的重要环节,探析苹果园土壤中氨氧化微生物氨单加氧酶基因(amoA)丰度与土壤硝化强度(Potential Nitrification,PN)和土壤理化性质的相关性,有助于评价土壤氨氧化微生物类群在苹果园土壤生态系统中的作用。【方法】本研究以辽宁省丹东东港地区‘寒富’苹果园土壤为研究对象,采用实时荧光定量PCR(Real-time PCR)技术,检测苹果树不同生育时期, 4月28日(萌芽期)、 7月24日(新梢停长期)、 10月23日(落叶期)的两个苹果园(分别编号为D1和D2)的土壤理化性质、 土壤硝化强度、 氨氧化古菌(Ammonia-oxidizing archaea, AOA)和氨氧化细菌(Ammonia-oxidizing bacteria, AOB)的amoA基因丰度,并分析了氨氧化微生物丰度与土壤理化性质和土壤硝化强度之间的关系。【结果】不同生育时期‘寒富’苹果园土壤理化因子差异较大。所有供试土壤的硝态氮(NO-3-N)、 速效磷(AP)和速效钾(AK)含量在4月份最高,铵态氮(NH+4-N)含量在7月最高,NO-3-N、 NH+4-N、 AP和AK含量在10月多为最低。且所有供试土壤pH值均在4.25~6.09之间。同一生育时期内,D2土壤pH均显著高于D1土壤,但其NO-3-N和NH+4-N含量则不同程度地低于D1土壤。不同采样时期的果园土壤硝化强度随季节变化表现出先降后增的趋势,除7月D2土壤硝化强度显著高于D1土壤外,4月与10月D2土壤硝化强度均显著低于D1土壤。尽管不同采样时期的土壤AOA与AOB丰度随生育期而各异,所有供试土壤中AOA丰度均显著高于AOB丰度。同一时期内,D2土壤AOA和AOB丰度均显著高于D1土壤。尽管土壤pH、 NO-3-N与AOA、 AOB均表现出显著相关性,土壤PN仅与AOA丰度明显正相关。【结论】长期施肥导致苹果园土壤pH值降低,pH值的改变是影响AOA与AOB丰度的重要因子,果园土壤的硝化过程主要由AOA来完成,土壤硝化强度与季节变化引起的温度和土壤环境因子等的改变密切相关。苹果园无机氮肥混合有机肥的施入,同时结合自然生草、 人工刈割等管理制度,在一定程度上可改变土壤氮素的含量与种类,减缓土壤酸化。     

连作马铃薯不同生育期根系分泌物的成分检测及其自毒效应

为探讨马铃薯连作障碍的可能机理,在大田条件下,以轮作为对照(CK),收集连作5年(CP5)马铃薯植株在不同生育期的根系分泌物,采用GC-MS对根系分泌物的主要成分进行了鉴定,并通过生物检测验证了根系分泌物的自毒效应。结果表明:CK和CP5处理的马铃薯在不同生育期的根系分泌物均鉴定出糖类、酸类、胺类、脂类、醇类和嘧啶类等成分,以糖类和酸类物质居多;CP5处理根系分泌物的成分较CK复杂,酸类物质含量有升高的趋势。连作改变了马铃薯根系分泌物的化学组成和含量:CP5处理在苗期、现蕾期和开花期的根系分泌物中均鉴定出邻苯二甲酸二丁酯,相对含量分别为0.16%、0.21%和0.24%,CK处理未检测到;CP5处理在苗期、现蕾期和开花期的根系分泌物中均鉴定出棕榈酸,相对含量分别为0.34%、1.12%和0.47%,CK处理仅在现蕾期和开花期鉴定出棕榈酸的存在,但相对含量仅为0.56%和0.24%。生物检测试验结果表明,棕榈酸和邻苯二甲酸二丁酯显著抑制了马铃薯生长,1 mmol·L-1棕榈酸和邻苯二甲酸二丁酯对马铃薯生长的抑制作用远远大于0.5 mmol·L-1的抑制作用。棕榈酸和邻苯二甲酸二丁酯是马铃薯根系分泌的自毒物质,但二者未表现出物质的叠加效应。现蕾期马铃薯根系分泌物所含的物质最多,是马铃薯根系分泌物收集的适宜时期。     

不同生长期互花米草的理化特性及厌氧发酵特性

为了解不同生长阶段互花米草的理化特性及厌氧发酵性能,找出互花米草的最佳收获期,进行了不同生长阶段互花米草的中温厌氧消化试验。结果表明,随着生长期的延长,互花米草中易分解有机物含量下降,木质纤维素含量增加,木质纤维结构发育逐渐成熟,坚韧度增加,纤维素的结晶度提高,C/N增加,互花米草的可生物降解性能降低,但由于金属阳离子含量降低,对厌氧微生物产生抑制的风险降低。互花米草直接厌氧发酵的厌氧生物转化率较低,最高的为5月份采收的互花米草,为42.55%,最低的为11月份采收的互花米草,仅为18.76%。从互花米草生物量以及产气稳定性等角度综合考虑,选择8月份作为互花米草的最佳采收时期。     

Influence of foliar application of mineral nutrients at different growth stages of guava

Foliar application of nutrients enhances efficient use along with quick response. The experiment was undertaken to study the effect of foliar application of mineral nutrients viz., boron (B), zinc (Zn), calcium (Ca), and potassium (K) sprayed at different growth stages viz., at fruit set and at two weeks after fruit set of guava (Psidium guajava L.). Increase in plant canopy and minimum seed index was in Zn (0.03%) sprayed at fruit set. Fruit size, sugar: acid, and organoleptic score were better in K (0.5%) sprayed at two weeks after fruit set. Increased yield in Zn (0.01%) and pectin enhancement with B (0.03%) was found at two weeks after fruit set, respectively. Minimum physiological loss in weight of fruits was with Ca (0.5%) sprayed at two weeks after fruit set. In general, for most of the desirable characters 0.5% potassium (K) spray at 2 weeks after fruit set had better results.     

不同生长期小麦茎秆力学性质与形态特性的相关性（简报）

为了研究小麦茎秆生物力学性质指标与小麦优种特性的相关性,以正在优种选育过程中的4个北方小麦品种为研究对象,试验测定了开花期、乳熟期及蜡熟期茎秆基部第二节间的惯性矩、拉伸强度、弯曲强度、剪切强度、弹性模量、抗弯刚度等生物力学指标及小麦形态、生理特性指标值;应用SAS软件进行相关性分析,筛选出了开花期主要生物力学评价指标为弯曲强度,乳熟期为抗弯刚度.并且确定了与相应生物力学相关度较大的形态、生理特性指标,开花期为:外径、茎秆干质量、株高、节间距、含水率、壁厚、穗质量;乳熟期为穗质量、外径、株高、叶鞘高、茎秆干质量.并且随着生长期的不同,相关度也不同,尤其是与含水率的相关度逐渐减小.该研究为建立生物力学指标评价体系提供了选择依据.     

马铃薯不同生育期追施钾肥增产效果的研究

在我国马铃薯主产区黑龙江省克山县 ,通过二年试验 ,研究了马铃薯不同生育期追施钾肥对产量及相关性状的影响。结果证明 ,追施钾肥能明显提高马铃薯的产量、淀粉含量和商品率 ,提高生育后期叶片叶绿素含量和光合强度 ,延缓生育后期的衰老 ,延长生育期。不同时期追施钾肥的效果不同 ,以现蕾初期追施钾肥效果最佳