Effect of salinity on water stress, growth, and yield of maize and sunflower

Maize and sunflower were grown in tanks filled with loam and clay, and were irrigated with water of three different levels of salinity. Predawn leaf-water potential and stomatal conductance were used as parameters for water stress. The predawn leaf-water potential of maize was higher than that of sunflower, but the effect of salinity and soil texture on the predawn leaf-water potential was the same for both crops. The stomatal conductance of sunflower was much higher and more severely affected by salinity and soil texture than the stomatal conductance of maize.

Although salinity had a more serious effect on the development of leaf area and canopy dry matter of sunflower, its effect on evapotranspiration and grain yield was the same for both crops. Soil texture had a stronger effect on the development of leaf area and canopy dry matter of sunflower, which also appeared in the evapotranspiration and grain yield, indicating that sunflower is more sensitive to drought than maize.     

Vegetative compatibility of cotton-defoliating <Emphasis Type="Italic">Verticillium dahliae</Emphasis> in Israel and its pathogenicity to various crop plants

Verticillium dahliae isolates recovered from a new focus of severe Verticillium wilt of cotton in the northeast of Israel were tested for vegetative compatibility using nitrate non-utilizing (nit) mutants and identified as VCG1, which is a new record in Israel. Other cotton isolates of V. dahliae from the northern and southern parts of the country were assigned to VCG2B and VCG4B, respectively. VCG1 isolates induced severe leaf symptoms, stunting and defoliation of cotton cv. Acala SJ-2, and thus were characterized as the cotton-defoliating (D) pathotype, whereas isolates of VCG2B and VCG4B were confirmed as the earlier described defoliating-like (DL) and non-defoliating (ND) pathotypes, respectively. This is the first record of the D-pathotype in Israel. The host range of representative isolates of each VCG-associated pathotype was investigated using a number of cultivated plants. Overall, the D isolates were more virulent than DL isolates on all tested host plants, but the order of hosts (from highly susceptible to resistant) was the same: okra (Hibiscus esculentus local cultivar), cotton (Gossypium hirsutum cv. Acala SJ2), watermelon (Citrullus lanatus cv. Crimson Sweet), safflower (Carthamus tinctorius cv. PI 251264), sunflower (Helianthus annuum cv. 2053), eggplant (Solanum melongena cv. Black Beauty), and tomato (Lycopersicon esculentum cv. Rehovot 13). The pattern of virulence of ND isolates differed from that of D and DL isolates, so that the former were highly virulent on eggplant but mildly virulent on cotton. Tomato was resistant to all cotton V. dahliae isolates tested. RAPD and specific PCR assays confirmed that the D isolates from Israel were similar to those originating from other countries.     

Temporal dynamics of light and nitrogen vertical distributions in canopies of sunflower, kenaf and cynara

To enhance eco-physiological and modelling studies, we quantified vertical distributions of light and nitrogen in canopies of three Mediterranean bio-energy crops: sunflower (Helianthus annuus), kenaf (Hibiscus cannabinus) and cynara (Cynara cardunculus). Field crops were grown with and without water stress in 2008 and 2009. Canopy vertical distributions of leaf area index (LAI), photosynthetically active radiation (PAR), specific leaf area (SLA), nitrogen concentration (N_conc) and specific leaf nitrogen (SLN) were assessed over time for each crop × year × water input combination. Light and nitrogen distributions were quantified by the Beer's law (exponential model) and extinction coefficients for light (K_L) and nitrogen (K_N) were calculated. Within a year, K_L did not change significantly over the studied period in all irrigated crops, but differences in K_L were significant between years (sunflower: 0.74 vs. 0.89; kenaf: 0.62 vs. 0.71; cynara: 0.77). K_L estimates were always lower (−48 to −65%) in water-stressed sunflower and kenaf crops because of the reduction in leaf angle. These results should be taken into account, when simulating water-limited biomass production. Vertical SLN distributions were found in canopies when LAI was >1.5 (40 from 51 cases). These distributions were significantly correlated with the cumulative LAI from the top (r² = 0.75-0.81; P < 0.05), providing parameters to upscale photosynthesis from leaf to canopy levels. Vertical SLN distributions followed species-specific patterns over the crop cycle and varied less compared to PAR distributions between years. Lastly, we observed strong associations between SLN and PAR distributions in irrigated sunflower and kenaf canopies (r² > 0.66; P < 0.001). However, observed SLN distributions were less steep than the distributions that would maximize canopy photosynthesis.     

Antioxidant potential of sesame (Sesamum indicum) cake extract in stabilization of sunflower and soybean oils

Recently natural antioxidants have gained increased interest because natural food ingredients are safer than synthetic ones. Antioxidant activities and protective effects of sesame cake extract (SCE) in stabilizing sunflower oil (SFO) and soybean oil (SBO) were tested. Since different antioxidant compounds have different mechanisms of action, 2,2-azinobis (3-ethylbenzthiazoline sulfonate) (ABTS) radical scavenging activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, and β-carotene/linoleic acid test system were used to assess the antioxidant efficacy of SCE. Total phenolic, flavonoid and flavonol contents in SCE were 1.94 (mg gallic acid equivalent (GAE) g⁻¹ dry weight (DW)), 0.88 (mg quercetain equivalent (QE) g⁻¹ DW), and 0.40 (mg QE g⁻¹ DW), respectively. Protective effects of SCE in stabilizing SFO and SBO were tested, compared to synthetic antioxidants, by measuring their peroxide values (PV), conjugated dienes (CD), conjugated trienes (CT) and p-anisidine value during accelerated storage. Results indicated that SCE exhibited stronger antioxidant activity in SFO and SBO than butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), while its antioxidant activity was less than that of tert-butyl hydroquinone (TBHQ).     

向日葵主要农艺与品质性状配合力及杂种优势分析

选用6份不育系和6份恢复系材料为亲本,按照NCⅡ不完全双列杂交设计配制36份向日葵杂交组合,对其组合的7个主要农艺性状和2个品质性状的亲本配合力及杂种优势进行分析。结果表明:36份杂交组合的主要农艺和品质性状间存在显著的遗传差异。其中株高、茎粗、叶片数、盘径、百粒质量、粗蛋白各性状同时受基因加性效应和非加性效应的共同作用,但基因非加性效应大于加性效应;单盘实粒数、单株产量、粗脂肪等性状受基因加性效应主导;广义遗传力大小顺序为:百粒质量单株产量单盘实粒数。亲本一般配合力(GCA)和特殊配合力(SCA)与向日葵杂交组合竞争优势呈极显著正相关。强优势组合特点是双亲或亲本之一具有较高的GCA效应或SCA效应。12份亲本材料中,恢复系X3639R、318R、LD5009R在单株产量、农艺性状、单盘实粒数均表现为较大的正向GCA效应值;不育系S10-390-3A、S10-336-2A、S10-390-1A在百粒质量、单株产量、粗脂肪、粗蛋白方面均表现为较大的正向GCA效应值,故均为较好的亲本材料。此外,除茎粗外,恢复系的GCA效应对杂种优势的贡献明显高于不育系。向日葵杂交组合主要农艺和品质性状存在广泛的杂种优势。叶片、单盘实粒数、单株产量平均超亲优势分别为66.13%、73.58%、61.17%。粗蛋白平均超亲优势值为68.96%,各性状正向超亲优势组合数超过83%。     

人工老化对向日葵种子活力及生理特性的影响（摘要）

[目的]研究生人工老化对向日葵种子活力及生理特性的影响。[方法]以‘Sunm20’、‘民乐深紫葵’、‘大山葵花4’和‘吉葵24’4份向日葵种质为材料,研究了高温高湿人工老化（100%RH,45℃）处理不同时间（0、2、4、6、8、10d）对种子发芽率、发芽势、发芽指数、活力指数、过氧化物酶（POD）、超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量的影响。[结果]随着向日葵种子老化时间的延长,发芽率、发芽势、发芽指数、活力指数、POD和SOD活性逐渐下降,MDA含量逐渐增加;不同种质的抗老化能力存在差异,其中‘Sunm20’比其他3份种质的抗老化能力强,在相同条件下,其种子活力和保护酶活性最高,MDA含量最低,并且在老化过程中,其种子活力变化及保护酶活性变化最慢。[结论]老化过程中保护酶POD、SOD活性的显著降低可能是导致种子活力下降的主要原因,而少量MDA的逐渐积累促进了种子的老化。     

我国向日葵机械化生产概况、存在问题及建议

向日葵是中国五大油料作物之一,目前,全国向日葵种植面积维持在100万～120万hm2,总产量在170万t左右。近年来,由于种植向日葵的经济效益好,种植面积和区域不断扩大。随着向日葵种植面积的逐年增加和向日葵新品种的培育,对向日葵的机械播种、田间管理、机械收获等环节提出更高的要求。种植农艺与农业机械作业有机结合,是促进向日葵产业化发展的有效途径。     

葵花秸秆髓料缓冲包装材料的制备和性能

以废弃的葵花秸秆髓碎料为原料,制备缓冲包装材料,并通过GB/T8618—1987《包装用缓冲材料静态压缩试验方法》中的A法,对比发泡聚苯乙烯(EPS)的缓冲性能进行了系统的研究。以缓冲材料的密度、胶黏剂的选择、发泡剂的改性为主要影响因素,以缓冲性能为评价目标,优化出最佳的成型工艺,并对其力学性能进行初步的研究。结果证明:制得的缓冲材料最小缓冲系数为3.6,最大静曲强度为12.56MPa,所制得的缓冲材料对被包装物具有优良的保护作用,可以替代石化产品——发泡聚苯乙烯泡沬塑料作为新型的缓冲包装材料。     

不同育苗时期对向日葵生长发育及产量的影响

春小麦收割后复种向日葵(向日葵育苗移栽)较小麦单作具有明显的增效优势。不同育苗时间相比较,育苗时间早,株高、茎粗和叶片数增加,千粒重增加。相同育苗时间,不同品种间株高、茎粗、千粒重差异显著。试验结果表明:向日葵复种生产,要选择优势品种并确定适宜的育苗时间和移栽时间。提早育苗并移栽,延长了向日葵生育期,产量增加29.01%~48.85%;不同密度处理,DK909和LH135产量之间差异极显著。