锌对不同油菜品种的生理特性、光合作用、根尖细胞超微结构及籽粒锌积累的影响

采用盆栽实验研究了Zn (0、1.0、5.0、10.0和20.0 mg·kg ^-1)对不同油菜品种(‘罗平金菜子’ (Brassica juncea)、‘二牛尾’ (B. juncea)、‘溧阳苦菜’ (B. juncea)、‘南通黄油菜’ (B. chinensis)、‘H33’ (B. napus))的光合特性、根尖细胞超微结构及籽粒富锌的影响。结果显示, 5个油菜品种在品种之间、Zn处理浓度之间, 根、茎、叶、籽粒及植株干重、光合特性、Zn含量和积累量的差异性均达到显著水平; 品种与Zn浓度的交互效应也达到显著水平。在Zn ≤ 5.0 mg·kg ^-1范围内, Zn增加了超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)等抗氧化酶活性、净光合速率(P_n)、气孔导度(G_s)以及蒸腾速率(T_r), 提高了油菜茎、叶、籽粒干重及总干重。油菜产量(籽粒干重)在5.0 mg·kg ^-1 Zn时达到最大值, 各品种分别较对照增加了37.7%、23.4%、29.5%、82.6%和18.0%。在Zn处理浓度为20.0 mg·kg ^-1时, ‘罗平金菜子’、‘二牛尾’、‘南通黄油菜’和‘溧阳苦菜’根尖细胞出现不同程度的线粒体肿胀、细胞壁增厚、细胞核萎缩且内容物较少, 而‘H33’中根尖细胞结构较CK处理差异不明显, 细胞结构较为完整。5个品种的籽粒Zn积累量随Zn浓度先增加, 在5.0 mg·kg ^-1 Zn时达到最大值, 然后下降。‘二牛尾’的籽粒Zn含量和籽粒Zn积累量在5.0和10.0 mg·kg ^-1 Zn处理时为5个品种最高或次高, 分别为172.34和164.10 mg·kg ^-1、2.932和2.575 mg·pot ^-1。     

播种期和种植密度对冬油菜籽粒产量和含油率的影响

通过田间试验研究了播种期和种植密度对冬油菜籽粒产量和含油率的影响.结果表明： 播种期主要影响分枝花序籽粒产量,而种植密度不仅影响分枝花序籽粒产量,还对主花序籽粒产量产生一定影响;籽粒含油率不受播种期的影响.主花序籽粒产量占单株籽粒产量的比例随种植密度的增加而升高,主花序籽粒含油率比分枝花序高约1%,因此小区籽粒含油率随种植密度的增加显著升高.研究区冬油菜播种期不能晚于10月中旬,10月下旬播种会显著降低籽粒产量;种植密度在每平方米36～48株可以提高冬油菜籽粒产量和含油率.     

Effects of crop plants on abundance of Pochonia chlamydosporia and other fungal parasites of root‐knot and potato cyst nematodes

The effects of a host plant on reproduction/abundance of fungal populations in relation to soil nutrients released by plants in the rhizosphere were studied. Abundance in the soil and potato rhizosphere of the fungi Paecilomyces lilacinus, Monographella cucumerina (CABI 380408) and Pochonia chlamydosporia var. chlamydosporia (Pc280, potato cyst nematode biotype) and P. chlamydosporia var. catenulata (Pc392, root‐knot nematode biotype) were assessed. The different ability of break crops (oilseed rape, sugarbeet and wheat) in the potato rotation to support Pa. lilacinus, Pochonia isolates Pc280 and Pc392 and abundance of the latter two isolates in soil and rhizosphere of potato plants infected with Meloidogyne incognita were also studied. Potato chits and crop seedlings were planted into boiling tubes containing 5000 chlamydospores or conidia g^?1 in acid washed sand (pH 6) and kept in a growth chamber at 20°C, and 16 h of light for up to 9 weeks. The abundance of the fungi in sand (fallow) differed significantly between fungal species, being in general less abundant in the absence than in the presence of the plant, although there was no interaction between plant species and fungal isolate. There was evidence of a different response to Me. incognita for Pc392 than for Pc280 but there was no significant effect of the presence of the nematode on the rate of increase of the fungus.     

自交对白菜型冬油菜生理生化特性及抗寒性的影响

为了解自交对白菜型冬油菜后代生理生化特性及抗寒性的影响,以6份白菜型冬油菜为材料,研究了在越冬降温前与降温后,自交和开放授粉后代植株叶片生理生化指标及越冬率的变化。结果表明:(1)除MDA含量外,无论是降温前还是降温后,白菜型冬油菜自交后代植株叶片中的SOD、CAT、POD的活性以及可溶性蛋白和游离脯氨酸含量都较开放授粉表现出不同程度的降低,其幼苗越冬率也较开放授粉植株显著降低。(2)与降温前相比,降温后所有测定指标在两种授粉方式后代中都表现为上升的趋势,其中以CAT活性变化最为显著。研究认为,自交会使白菜型冬油菜后代植株叶片中保护酶活性及可溶性蛋白和游离脯氨酸含量明显降低,MDA含量升高,导致幼苗的越冬率显著下降,进而引起其植株抗寒性减弱。     

Characterization of Bacteria in the Rhizosphere Soils of Polygonum Pubescens and Their Potential in Promoting Growth and Cd,Pb, Zn Uptake by Brassica napus

Microbe-enhanced phytoremediation has been considered as a promising measure for the remediation of metal-contaminated soils. In this study, two bacterial strains JYX7 and JYX10 were isolated from rhizosphere soils of Polygonum pubescens grown in metal-polluted soil and identified as of Enterobacter sp. and Klebsiella sp. based on 16S rDNA sequences, respectively. JYX7 and JYX10 showed high Cd, Pb and Zn tolerance and increased water-soluble Cd, Pb and Zn concentrations in culture solution and metal-added soils. Two isolates produced plant growth-promoting substances such as indole acetic acid, siderophore, 1-aminocyclopropane-1-carboxylic deaminase, and solubilized inorganic phosphate. Based upon their ability in metal tolerance and solubilization, two isolates were further studied for their effects on growth and accumulation of Cd, Pb, and Zn in Brassica napus (rape) by pot experiments. Rapes inoculated with JYX7 and JYX10 had significantly higher dry weights, concentrations and uptakes of Cd, Pb, Zn in both above-ground and root tissues than those without inoculation grown in soils amended with Cd (25 mg kg^?1), Pb (200 mg kg^?1) or Zn (200 mg kg^?1). The present results demonstrated that JYX7 and JYX10 are valuable microorganism, which can improve the efficiency of phytoremediation in soils polluted by Cd, Pb, and Zn.     

Balancing bioenergy and biosecurity policies: estimating current and future climate suitability patterns for a bioenergy crop

In an apparent paradox, bioenergy crops offer potential benefits to a world adjusting to the challenges of climate change and declining fossil fuel stocks, as well as potential ecological and economic threats resulting from biological invasions. In considering this paradox it is important to understand that benefits and threats may not always be apparent in equal measure throughout the potential range of each candidate biofuel species. In some environments, a species could potentially produce valuable biological materials without posing a significant invasion threat. In this study, we develop a bioclimatic niche model for a candidate biofuel crop, Millettia pinnata, and apply the model to different climatic and irrigation scenarios to estimate the current and future patterns of climate suitability for its growth and naturalization. We use Australia as a case study for interpreting the niche model in terms that may be informative for both biofuels proponents and biosecurity regulators to plan management programmes that reflect the invasive potential in different areas. The model suggests that suitable growing conditions for M. pinnata in Australia are naturally restricted to the moist and semimoist tropics. Irrigation can extend the suitable growing conditions more widely throughout the tropics, and into more arid regions. Under future climate scenarios, suitable growing conditions for M. pinnata under natural rainfall contract towards the east coast, and extend southward into the subtropics. With irrigation, M. pinnata appears to have the potential in the future to naturalize across much of Australia. The bioclimatic modelling method demonstrated here is comparatively quick and easy, and can produce a rich array of data products to inform the interests of both bioenergy proponents and biosecurity regulators. We show how this modelling can support the development of spatially explicit biosecurity policies designed to manage invasion risks in a manner that balances bioenergy and biosecurity concerns.     

Formulations of Bacillus subtilis BY-2 suppress Sclerotinia sclerotiorum on oilseed rape in the field

We are developing a collection of Bacillus strains, isolated from different environments, for use in controlling Sclerotinia sclerotiorum on oilseed rape in China and elsewhere. Strain BY-2, isolated from internal tissues of an oilseed rape root, was demonstrated to be Bacillus subtilis based on biochemical and morphological characteristics and on 16S RNA gene sequence. Photographic evidence from gnotobiotic studies using the lacZ-tagged strain BY-2(pUC18) confirmed that this strain was capable of colonizing internal root tissues. Strain BY-2 did not effectively colonize the ectorhizosphere or the surface of the stems or leaves of oilseed rape when applied in pellet or wrap seed treatment formulations. Populations of BY-2 dropped from 10⁸ CFU seed⁻¹ to 10⁴ CFU g root⁻¹ and ⩽10² CFU g stem⁻¹ or leaf⁻¹ after 60 days. Strain BY-2 was applied as a pellet seed treatment formulation alone, as a spray at flowering alone, and as the pellet seed treatment formulation combined with the spray application in two field trials at the Wuxue location conducted in two consecutive years. These three treatments containing BY-2 provided disease control (disease incidence) and mean seed yield that was similar to the chemical control treatment and significantly greater than the pellet without bacteria and non-treated control treatments. All three of these BY-2 treatments were similar to each other with regard to these two metrics and to treatments containing B. subtilis Tu-100, a genetically distinct strain previously shown to be effective against this disease. In two additional field trials, conducted in consecutive years at the Wuhan location, strain BY-2 applied as a wrap seed treatment formulation alone, as a spray at flowering alone, and as the wrap seed treatment combined with the spray application provided disease control (disease incidence) and mean seed yield that was similar to the chemical control treatment. These three BY-2 treatments also were significantly greater than the non-treated control treatments and compared favorably to treatments containing Tu-100. There was no evidence of BY-2 promoting growth of oilseed rape when applied in the pellet or wrap seed treatment formulations in field trials conducted at the Wuxue or at the Wuhan locations. We now have three Bacillus strains (B. subtilis strains BY-2 and Tu-100, B. megaterium A6) that control S. sclerotiorum on oilseed rape in the field that can be tested in strain combinations for enhanced disease control. We also have multiple methods for application of Bacillus strains as both seed treatment and foliar applications were effective.     

钙对土壤镉有效性的影响及其机理

采用盆栽试验,研究了赤红壤上两种镉污染水平下,施用4种钙量（0、40、100、200 mg·kg^-1）对小油菜生物量、镉吸收量及土壤溶液中钙、镉浓度的影响.结果表明：在低镉或者高镉污染水平下,与对照相比,小油菜干质量均以高钙用量处理的增幅最大,两季平均增加了5.5%（低镉）和17.3%（高镉）;增加钙的施用量,使土壤溶液中钙浓度明显增加,小油菜体内钙浓度也明显增加;当钙施用量为100 mg·kg^-1时,土壤溶液中镉浓度较对照分别增加74.5%（低镉）和31.0%（高镉）,而小油菜体内镉浓度较对照分别降低4.5％（低镉）和13.1％（高镉）.两种镉污染水平下,土壤溶液中钙/镉（质量比）值与小油菜体内镉浓度均呈显著正相关.土壤溶液中钙/镉比值影响土壤镉的有效性,进而影响小油菜对镉的吸收.     

土壤水分和供硼状况对不同硼效率油菜苗期生长、水分含量和硼形态的影响

通过土培试验,研究了土壤水分和供硼状况对不同硼效率油菜苗期生长、叶片水分含量和硼形态的影响.结果表明:低水分胁迫条件下,硼高效甘蓝品种和硼低效甘蓝品种在高供硼水平下的单株鲜质量比低供硼水平分别增加了43.1%和31.7%,但品种间没有显著差异;硼高效品种在两种供硼水平下的束缚态水分含量分别比低效品种高11.4%和1.7%,半束缚态硼分配比例分别比低效品种高6.9%和23.8%.正常水分条件下,硼高效甘蓝品种和硼低效甘蓝品种在高供硼水平下的单株鲜质量比低供硼水平分别增加了11.1%和27.4%;硼高效品种在两种供硼水平下的自由态水分含量较硼低效品种多,自由态硼累积量为低效品种的2倍多,这有利于硼在高效植物体内的移动运输.