缺硼对棉花、黄瓜和油菜乙烯释放的影响

本试验通过水培和土培试验的方法,研究了缺硼对棉花、油菜和黄瓜乙烯释放的影响。结果表明：缺硼条件下,棉花、黄瓜乙烯释放量显著增加,而油菜无论缺硼和正常硼条件下,乙烯释放量较低且没有明显差异,乙烯释放量的增加对棉花和黄瓜的生长发育有抑制作用;喷施乙烯合成抑制剂和乙烯生理效应抑制剂在一定程度上能减轻棉花和黄瓜的缺硼症状。黄瓜水培结果表明：在黄瓜缺硼症状出现前,乙烯释放量没有明显增加,随着缺硼时间的延长,缺硼症状的出现,乙烯释放量显著增加,因而乙烯释放量的增加不是缺硼导致黄瓜生理失调的直接反应。     

不同硼效率甘蓝型油菜品种细胞壁中硼的分配

应用不同硼效率甘蓝型油菜品种 ,研究硼在细胞壁中的分配。硼主要结合在细胞壁中 ,缺硼显著提高硼在细胞壁中的分配比例。根系细胞壁硼含量显著低于叶片 ,但根系细胞壁硼占根系总硼量之比例显著高于叶片。同一品种根系及其细胞壁、老叶细胞壁硼含量受生育期影响较小 ,新叶及其细胞壁、老叶硼含量受生育期影响较大。在正常供硼条件下 ,硼高效品种根系细胞壁和叶片细胞壁硼含量均低于低效品种 ;正常和缺硼条件下 ,硼高效品种细胞壁硼占器官总硼量之比例均低于低效品种。说明硼低效品种需较多的硼构建细胞壁。     

缺硼与低温对黄瓜幼苗—些生理反应的影响

营养液培养试验表明,缺硼明显降低黄瓜幼苗植株的生长量,植株叶片细胞质膜K 的渗漏增加,细胞结构受损。此外,叶片中蔗糖和还原糖都明显积累。缺硼的上述反应在低温胁迫（7－8℃,FX25－28℃为对照）时表现更为明显。试验结果表明硼对于细胞膜的完整性具有重要的作用;充分供硼可以减轻低温对细胞膜的伤害。     

油菜幼苗对硼的吸收与运转及钙的影响

硼促进油菜幼苗生长和对N、P、K、Ca 营养元素的吸收.当油菜生长介质中钙浓度增大时,植株吸硼量和硼在新叶中的积累减少,老叶中积累增加。硼在油菜体内的运转系数在低硼条件下较大,并随钙处理水平的增加而下降.结果表明,在硼素供应有限的条件下,油菜体内硼仍具一定的移动性,钙则使硼的吸收和移动性下降.     

缺硼与低温对黄瓜幼苗的一些生理反应的影响

营养液培养试验表明,缺硼明显降低黄瓜幼苗植物的生长量,植株叶片细胞质膜Ｋ＾＋的渗漏增加,细胞结构受损。此外,叶片中蔗糖和还原糖都明显积累。缺硼的上述反应在低温胁迫（７￣８℃,以２５￣２８℃为对照）时表现更为明显。试验结果表明硼对于细胞膜的完整性具有重要的作用;充分供硼可以减轻低温对细胞膜的伤害。     

外源一氧化氮对盐胁迫下黄瓜幼苗生长和渗透调节物质含量的影响

采用水培法,研究了外源一氧化氮(NO)对黄瓜幼苗生长和渗透调节物质含量的影响。结果表明:正常生长条件下添加外源NO能促进黄瓜幼苗生长,而添加NO信号传递途径关键酶——鸟苷酸环化酶抑制剂亚甲基蓝(MB-1)显著抑制了黄瓜幼苗的生长;盐胁迫条件下,添加外源NO明显缓解了盐胁迫对黄瓜幼苗生长的抑制,与单独盐处理比较,株高、茎粗、鲜质量、干质量显著增加,渗透调节物质如可溶性糖、可溶性蛋白和脯氨酸含量明显提高,而MB-1能够不同程度地消除NO的这些调节作用;NO对盐胁迫下黄瓜幼苗生长影响大于正常生长条件下黄瓜幼苗,NO的作用可能是通过鸟苷酸环化酶介导的。     

水稻铁害和应激乙烯释放的关系

在热带地区的水稻栽培中,常遇到水稻青铜病（ｂｒｏｎｚｉｎｇ）的危害．已知它是由水田中高浓度的亚铁离子所引起,故又叫铁害．但至今没有可靠的生理诊断指标用于抗性品种的筛选．本文研究了铁害与应激乙烯释放的关系,试图以应激乙烯的释放作为铁害的生理诊断指标．试验用两种方法模拟水稻致病．第一种方法是将水稻离体叶片的剪口端浸入ＦｅＳＯ４溶液中,靠叶片蒸腾作用吸收Ｆｅ＋＋而致病．另一种方法是在水培培养液中加入ＦｅＳＯ４通过水稻根系吸收Ｆｅ＋＋而致病．研究结果表明,当处理离体叶片时,发病强度和应激乙烯释放量呈显著相关,但叶片内铁含量的增加与发病强度和应激乙烯释放都没有相关性．而处理完全植株时,叶片中乙烯释放几乎不受影响．当部分或全部切除根时,叶片中乙烯释放则可被亚铁离子激发。表明水稻根系限制了Ｆｅ＋＋的吸收速率,而Ｆｅ＋＋进入叶组织的速率又决定应激乙烯的释放和组织的伤害程度．因此,叶片应激乙烯的释放作为铁害的生理诊断指标只有在当根系受到某种伤害时才可能适用,譬如移栽和毒性土壤等因素造成的根系的伤害．     

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.     

不同供硼水平对绿豆植株形态及其叶片生长特征的影响

利用水培以绿豆为材料,研究不同供硼水平对绿豆植株形态和叶片生长特征的影响。结果表明缺硼抑制绿豆生长,但对根的影响较对冠的影响更大,表现在缺硼导致冠根比增大;缺硼明显抑制叶面积;降低特定叶面积（SLA）,这可能是由于缺硼影响细胞伸展的缘故,造成叶片密度增加,缺硼也提高叶片重量比（LWR)并导致叶脉间失绿,说明缺硼叶片可能过量碳水化合物积累,引起叶绿素降解,与适量供硼比较,过量供硼也影响绿豆的生长,但对冠根比没有影响,表明过量供硼对根和冠具有相同的抑制作用,硼中毒导致成熟叶片脱落,从而影响叶面积,但对特定叶面积（SLA）和叶片重量比（LWR）没有影响。     

不同棉蚜种群对棉花和黄瓜的适合度分化

通过室内转接试验,研究来源于越冬寄主花椒、木槿、石榴和夏寄主棉花、黄瓜共5个棉蚜Aphids gossypii Glover种群对棉花和黄瓜的适合度。结果表明:花椒棉蚜、木槿棉蚜、棉花棉蚜转接到棉花上的成虫留居率和种群繁殖率均明显地高于黄瓜;黄瓜棉蚜转接到棉花上的成虫留居率和种群繁殖率均显著地低于黄瓜;石榴棉蚜转接到棉花上的种群繁殖率显著低于黄瓜,但成虫留居率在2种寄主之间没有明显差异。     

Responses of rape genotypes to boron application

Pot and field experiments were conducted to examine the effect of boron on the yield and quality of different rape genotypes and to identify cultivar variation in some physiological responses to boron. B fertiliser can significantly increase the yields of both traditional and high-quality rape. Significant differences in yield response to boron application were found between cultivars. High quality varieties were more sensitive to boron deficiency than a traditional variety. Application of boron increased plant height, net photosynthetic rate, activity of nitrate reductase (NRA) and dry-weight yield, and decreased the contents of erucic acid and glucosinolate in both traditional and high-quality rape varieties. Boron plays a positive role in keeping the stability of the good characteristics of high quality cultivars.     

氮磷钾、硼水平对不同基因型油菜硼吸收及某些生物学性状的影响

采用温室土培试验,研究了不同氮磷钾复合型（NPK肥）施用水平下,油菜对B的吸收及其耐缺B机理以及缺B对某些生物学性状的影响,结果表明,缺B时,随NPK肥施用量的增加,油菜植株缺B症状加重,苗期叶面积及其生长速率减小,叶绿素含量增加,硝酸还原酶活性下降,成熟期单株有效分枝,有效角果数减少,籽粒产量降低,可以认为,油菜大苗期最新展开叶（YOL）与最新成熟叶（YML）的B浓度比值可作为不同基因型油菜植株体内B移动性大小的判氟指标,B移动性及B利用率的大小是不同基因型油菜耐缺B的重要营养机理之一。     

不同土壤水分状况下施硼对油菜硼吸收、利用的影响

1　引　　言我国是油菜生产大国 ,也是一个土壤缺Ｂ面积较大的国家 .由于油菜缺Ｂ问题突出 ,施用Ｂ肥已成为提高油菜产量、改善品质的重要措施[2 ,3 ,11] .但是 ,Ｂ肥的施用不但存在成本高、难度大、效率低的问题 ,而且也存在造成环境污染的可能性[9] .研究表明[8,10 ] ,不同油菜品种对缺Ｂ的反应存在基因型差异 ,因此 ,筛选、培育Ｂ营养高效基因型油菜以适应缺Ｂ土壤环境是解决油菜缺Ｂ问题的最有效途径之一 .植物对土壤中Ｂ的吸收、运输及利用因土壤水分状况而异[4 ,5] .研究不同水分条件下尤其是干旱情况下Ｂ素营养对油菜Ｂ营养效率的影…     

Is ethylene involved in regulation of root ferric reductase activity of dicotyledonous species under iron deficiency?

Most dicotyledonous species respond to Fe deficiency by developing some mechanisms known as Fe-deficiency responses. The role of ethylene in regulation of root ferric reductase activity of wild-type tomato (Lycopersicon esculentum L.) and its mutant Never ripe (Nr), bean (Phaseolus vulgaris L., cv. Bifeng 80-30), and cucumber (Cucumis sativus L., cv. Xintaimici) plants grown in nutrient solution without Fe supply was studied under controlled condition. The results show that: (i) the tomato mutant Nr, which is insensitive to ethylene, presented rapid increase in root ferric reductase activity after omitting Fe from the nutrient solution; (ii) the initial time for increase in root ferric reductase activity was earlier than that in ethylene production after onset of Fe deficiency in the three species; (iii) like cobalt (3 μM Co²⁺), an inhibitor for ethylene production, high concentration of zinc (50 μM Zn²⁺) and copper (5 μM Cu²⁺) also suppressed the increase in root ferric reductase activity of Fe-starved plants; (iv) under Fe-sufficient conditions, indol-3-butylric acid (IBA) stimulated root ferric reductase activity of cucumber and bean plants, and this stimulating effect could not be suppressed by aminoethoxyvinylglycine (AVG, an inhibitor for ethylene synthesis). These results suggested that ethylene might not be directly involved in the regulation of root ferric reductase activity of Fe-deficient dicotyledonous species.     

Anatomical Studies on the Effects of Boron on the Development of Stamen and Pistil of Rape(Bassica napus)

The effect of boron deficiency (0. 02 ppm of hot water soluble boron soil)on the development of floral organs of NY-8 (Brassica nalrus L. )was obvious. Some abnormal features were observed: pollen sac shrinkage, abnormal development of tapetum, abortion occurred from the stage of PMC to the unicellular pollen ,stigma exposed,poor development of papillae, arrested differentiation of some ovules and embryo sacs etc. The results suggest that the abortion of stamen and pistil in rape may be one of the reasons for yield decrease     

Resistance of aphis gossypii (Homoptera: Aphididae) to fenvalerate and imidacloprid and activities of detoxification enzymes on cotton and cucumber

Resistance of two strains of cotton aphid, Aphis gossypii Glover, to fenvalerate and imidacloprid were determined on cotton (Gossypium hirsutum L.) and cucumber (Cucumis sativa L.) after resistance selection of one strain to fenvalerate for 16 consecutive generations, and of a second strain to imidacloprid for 12 consecutive generations on cotton in greenhouses. Dose-response and activities of detoxication enzymes of the fenvalerate-resistant strain (R-fenvalerate), the imidacloprid-resistant strain (R-imidacloprid), and a susceptible strain (S) were determined. After 16 consecutive generations of selection, resistance of A. gossypii to fenvalerate increased >29,000-fold and to imidacloprid 8.1-fold. On cucumber. resistance of the R-fenvalerate strain to fenvalerate increased 700-fold and to imidacloprid 3.6-fold. However, the most significant finding in this study was that the R-imidacloprid strain exhibited cross-resistance to fenvalerate, with a resistance ratio of 108.9-fold on cotton and 3:3.5-fold on cucumber, whereas the R-fenvalerate strain did not show significant cross-resistance to imidacloprid on either plant species. Both resistant strains of A. gossypii were more resistant to fenvalerate on cotton than on cucumber, whereas their susceptibility to imidacloprid on otton and cucumber were not significantly different. The response of the S strain to fenvalerate and imidacloprid were similar on cotton and Cucumber. Activities of acetylcholinesterase (AChE) and alpha-naphthylacetate (alpha-NA) esterases of A. gossypii were significantly different among the three strains, with the R-fenvalerate strains having the highest, followed by the R-imidacloprid strain, and the S strain the lowest. The activities of the AChE and alpha-NA esterases for all three strains were also significantly higher on cotton than on cucumber. The resistance mechanism and resistance management strategies for the R-fenvalerate and R-imidacloprid strains of A. gossypii to fenvalerate and imidacloprid on cotton and cucumber are discussed.     

The relationship of the peroxidative indoleacetic Acid oxidase system to in vivo ethylene synthesis in cotton

Since peroxidase and manganese have been implicated in both auxin destruction and ethylene production, the effect of auxins and high tissue levels of manganese on the peroxidative indoleacetic acid oxidase system and the internal level of ethylene was determined in cotton (Gossypium hirsutum L. cv. Watson GL-7). The highest level of manganese tested produced manganese toxicity symptoms, including necrotic lesions, accompanied by an increase in internal ethylene levels at about 15 days after treatment initiation. Statistically significant increases in indoleacetic acid oxidase and peroxidase activity were first observed 2 days later and were paralleled by tissue manganese levels above 7.4 milligrams per gram dry weight and internal ethylene levels of 0.77 microliters per liter air. Eight hours after application of 2,4-dichlorophenoxyacetic acid or indoleacetic acid, the internal levels of ethylene were increased to above 6.6 microliters per liter air in cotton plants, and levels of this magnitude were maintained for a 72-hour period of observation. Modification of peroxidase and indoleacetic acid oxidase activity in auxintreated plants definitely occurred well after the elevation of internal ethylene levels. While ethylene levels and indoleacetic acid oxidase activity were increased by both experimental approaches, the earlier appearance of increased ethylene indicates that the peroxidative indoleacetic acid oxidase system in cotton is not involved in ethylene synthesis or that this enzyme is not the rate-limiting factor when ethylene synthesis is increased. Ethylene, as well as auxin destruction, may be involved in some of the long term plant responses to toxic levels of manganese. The findings also suggest that auxin-induced ethylene may play a role in the elevation of peroxidase and indoleacetic acid oxidase activity eventually seen in extracts of plants treated with auxins. The data support the assumption that the enzymatic portion of the indoleacetic acid oxidase system in cotton is a peroxidase.     

The BnALMT1 and BnALMT2 genes from rape encode aluminum-activated malate transporters that enhance the aluminum resistance of plant cells

The release of organic anions from roots can protect plants from aluminum (Al) toxicity and help them overcome phosphorus (P) deficiency. Our previous findings showed that Al treatment induced malate and citrate efflux from rape (Brassica napus) roots, and that P deficiency did not induce the efflux. Since this response is similar to the malate efflux from wheat (Triticum aestivum) that is controlled by the TaALMT1 gene, we investigated whether homologs of TaALMT1 are present in rape and whether they are involved in the release of organic anions. We isolated two TaALMT1 homologs from rape designated BnALMT1 and BnALMT2 (B. napus Al-activated malate transporter). The expression of these genes was induced in roots, but not shoots, by Al treatment but P deficiency had no effect. Several other cations (lanthanum, ytterbium, and erbium) also increased BnALMT1 and BnALMT2 expression in the roots. The function of the BnALMT1 and BnALMT2 proteins was investigated by heterologous expression in cultured tobacco (Nicotiana tabacum) cells and in Xenopus laevis oocytes. Both transfection systems showed an enhanced capacity for malate efflux but not citrate efflux, when exposed to Al. Smaller malate fluxes were also activated by ytterbium and erbium treatment. Transgenic tobacco cells grew significantly better than control cells following an 18 h treatment with Al, indicating that the expression of BnALMT1 and BnALMT2 increased the resistance of these plant cells to Al stress. This report demonstrates that homologs of the TaALMT1 gene from wheat perform similar functions in other species.