Effects of potassium deficiency on photosynthesis and photoprotection mechanisms in soybean(Glycine max(L.)Merr.)

Potassium is an important nutrient element requiring high concentration for photosynthetic metabolism.The potassium deficiency in soil could inhibit soybean(Glycine max(L.) Merr.) photosynthesis and result in yield reduction.Research on the photosynthetic variations of the different tolerant soyben varieties should provide important information for high yield tolerant soybean breeding program.Two representative soybean varieties Tiefeng 40(tolerance to K~+ deficiency) and GD8521(sensitive to K~+ deficiency) were hydroponically grown to measure the photosynthesis,chlorophyll fluorescence parameters and Rubisco activity under different potassium conditions.With the K-deficiency stress time extending,the net photosynthetic rate(P_n),transpiration rate(T_r) and stomatal conductance(G_s) of GD8521 were significantly decreased under K-deficiency condition,whereas the intercellular CO_2 concentration(C_i) was significantly increased.As a contrast,the variations of Tiefeng 40 were almost little under K-deficiency condition,which indicated tolerance to K~+ deficiency variety could maintain higher efficient photosynthesis.On the 25 th d after treatment,the minimal fluorescence(F_0) of GD8521 was significantly increased and the maximal fluorescence(F_m),the maximum quantum efficiency of PSII photochemistry(F√F_m),actual photochemical efficiency of PSII(φ_(PSII)),photochemical quenching(q_p),and electron transport rate of PSII(ETR)were significantly decreased under K~+ deficiency condition.In addition,the Rubisco content of GD8521 was significantly decreased in leaves.It is particularly noteworthy that the chlorophyll fluorescence parameters and Rubisco content of Tiefeng 40 were unaffected under K~+ deficiency condition.On the other hand,the non-photochemical quenching(q_N) of Tiefeng 40 was significantly increased.The dry matter weight of Tiefeng 40 was little affected under K~+ deficiency condition.Results indicated that Tiefeng 40 could avoid or relieve the destruction of PSII caused by exceeded absorbed solar energy under K-deficiency condition and maintain natural photosynthesis and plant growth.It was an essential physiological mechanism for low-K-tolerant soybean under K-deficiency stress.     

Effects of maize (Zea mays L.) growth and photosynthesis on δ13C in soil respiration

As a safe, stable and practical labeling method, the natural abundance of ¹³C has been widely used in a carbon cycle in the soil-plant system. In order to understand the effects of maize growth and photosynthesis on the value of δ¹³C in soil respiration, the value of δ¹³C in soil respiration was determined by mass spectrum after being trapped in a NaOH solution under a closed static chamber and then turned into barium carbonate in a pot experiment. The results showed that maize growth and photosynthesis significantly affected the value of δ¹³C in the soil respiration. In maize-planted soil, the value of δ¹³C in soil respiration had a clear seasonal variation. It changed with maize growth in the range of −14.57‰ to −12.3‰ and decreased during the period of trumpeting > ripening > flowering stages. The difference of δ¹³C in soil respiration during various maize growth stages added up to about 2.3‰ However, in bare soil, δ¹³C in soil respiration ranged from −19.34‰ to −19.13‰ and did not change significantly over time. The δ¹³C in soil respiration in the maize-planted soil was the lowest at flowering stage. This was mainly due to the decline of the input in assimilates into soil and the decrease in root activity. However, the δ¹³C increased at ripening stage, due to the decomposition and ingestion of senescent and died roots by soil microorganisms. In the planted soil, δ¹³C in soil respiration was significantly higher during daytime than at nighttime at flowering and ripening stages. The difference of δ¹³C in soil respiration between day and night periods added up to about 1.4‰ and 2.1‰ at flowering and ripening stages, respectively. Shading maize plants at the trumpeting stage decreased the value of δ¹³C in soil respiration significantly. The difference of δ¹³C in soil respiration between the treatment of non-shading and shading plants added up to 2.85‰ It was concluded that δ¹³C in soil respiration was remarkably controlled by the maize growth and photosynthesis in planted soil. Soil respiration was mainly derived from the recent assimilates during maize growth. __________ Translated from Acta Ecologica Sinica, 2007, 27(3): 1072–1078 [译自: 生态学报]     

单一铵、硝营养对苗期淹水胁迫玉米光合与生物学性状的影响

【目的】研究NH4+-N和NO3--N及其不同供氮水平对苗期玉米抗淹水胁迫的影响,为采用氮营养调控途径提高玉米的抗涝性提供理论依据。【方法】采用室内砂砾培养及模拟淹水胁迫的方法,研究2个不同品种玉米(利民15和皖玉9号),分别在苗期供应NH4+-N和NO3--N 2种形态氮素以及高(7 mmol/L)、低(3 mmol/L)氮2个氮素水平时,其光合与生长对淹水胁迫的响应。【结果】在非淹水胁迫条件下,在高氮水平下2个玉米品种不同部位的生物量、株高、茎横截面积、根体积、光合速率、叶绿素含量和叶面积均相对高于低氮水平。但在淹水胁迫条件下,当NH4+-N供氮水平较低(3 mmol/L)时,2个品种玉米在苗期均表现相对较强的抗涝性;但在NO3--N营养条件下,供氮水平较高(7 mmol/L)时,表现相对较强的抗涝性。即分别在3 mmol/L NH4+-N、7 mmol/L NO3--N条件下,利民15和皖玉9号在淹水胁迫条件下可以维持相对较高的茎横截面积、根体积、光合速率、叶绿素含量和叶面积。【结论】在不同氮素营养条件下,苗期不同品种玉米抗涝性强弱随氮素供应形态和供应水平而异。     

普通玉米主要品质性状杂种优势研究

利用普通玉米的10个骨干自交系按不完全双列杂交法组配成45个组合,分析了10个自交系及其杂交一代的4个主要品质性状(粗淀粉、粗脂肪、粗蛋白、赖氨酸)的杂种优势及其亲子关系.结果表明:玉米4个品质性状的杂种优势以粗淀粉含量最强,其次是粗脂肪含量,而粗蛋白和赖氨酸含量呈现负的杂种优势,且各性状不同组合的杂种优势存在着较大差异;粗淀粉含量、粗脂肪含量和粗蛋白含量亲子相关性达到了显著或极显著水平,而赖氨酸含量亲子相关性极弱.     

Response of root morphology,physiology and endogenous hormones in maize(Zea mays L.) to potassium deficiency

Potassium(K)deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world.However,the physiological mechanism of K deficiency tolerance is not yet fully understood.To identify the differences of root morphology,physiology and endogenous hormones at different growing stages,two maize inbred lines 90-21-3(tolerance to K deficiency)and D937(sensitive to K deficiency)were cultivated in the long-term K fertilizer experimental pool under high potassium(+K)and low potassium(-K)treatments.The results indicated that the root length,volume and surface area of 90-21-3 were significantly higher than those of D937 under-K treatment at different growing stages.It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under-K treatment.Meanwhile,the values of superoxide dismutase(SOD)and oxidizing force of 90-21-3were apparently higher than those of D937,whereas malondialdehyde(MDA)content of D937 was obviously increased.Compared with+K treatment,the indole-3-acetic acid(IAA)content of 90-21-3 was largely increased under-K treatment,whereas it was sharply decreased in D937.On the contrary,abscisic acid(ABA)content of 90-21-3 was slightly increased,but that of D937 was significantly increased.The zeatin riboside(ZR)content of 90-21-3 was significantly decreased,while that of D937 was relatively increased.These results indicated that the endogenous hormones were stimulated in 90-21-3to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.     

Response of root morphology,physiology and endogenous hormones in maize(Zea mays L.) to potassium deficiency

Potassium(K)deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world.However,the physiological mechanism of K deficiency tolerance is not yet fully understood.To identify the differences of root morphology,physiology and endogenous hormones at different growing stages,two maize inbred lines 90-21-3(tolerance to K deficiency)and D937(sensitive to K deficiency)were cultivated in the long-term K fertilizer experimental pool under high potassium(+K)and low potassium(-K)treatments.The results indicated that the root length,volume and surface area of 90-21-3 were significantly higher than those of D937 under-K treatment at different growing stages.It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under-K treatment.Meanwhile,the values of superoxide dismutase(SOD)and oxidizing force of 90-21-3were apparently higher than those of D937,whereas malondialdehyde(MDA)content of D937 was obviously increased.Compared with+K treatment,the indole-3-acetic acid(IAA)content of 90-21-3 was largely increased under-K treatment,whereas it was sharply decreased in D937.On the contrary,abscisic acid(ABA)content of 90-21-3 was slightly increased,but that of D937 was significantly increased.The zeatin riboside(ZR)content of 90-21-3 was significantly decreased,while that of D937 was relatively increased.These results indicated that the endogenous hormones were stimulated in 90-21-3to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.     

光质对玉米叶片光合及光系统性能的影响

【目的】研究不同光质对玉米叶片光合作用及光系统性能的影响,旨在探讨阴天条件下光质变化对玉米光合作用影响的生理机理。【方法】在大田条件下,以郑单958（ZD958）和先玉335（XY335）为供试材料,设置3种光质处理,分别为红色膜（R）、蓝色膜（B）和绿色膜（G）,以白色纱网模拟阴天作为对照（CK）,试验于2013年4-6月在黄淮海玉米技术创新中心进行。于6片完全展开叶时进行光质处理,10 d以后,利用快速叶绿素荧光和820 nm光吸收技术测定气体交换参数、快速叶绿素荧光动力学曲线及820 nm光吸收量的变化,分析光质对玉米叶片光合作用和光系统性能的作用方式。【结果】阴天和模拟阴天条件下,各波段辐射能所占比例基本与晴天一致,但各波段光的绝对量均显著下降,其中蓝紫光下降最多。3种色膜处理中,蓝膜在蓝紫光和紫外光（300-510 nm）下降最少,且所占比例较自然光显著增加。不同色膜处理后,XY335和ZD958净光合速率（P_n）均显著下降,下降幅度表现为绿膜（G）＞红膜（R）＞蓝膜（B）,XY335下降幅度为40.13%、32.68%和22.00%,ZD958为46.92%、37.69%、27.46%。与对照相比,各处理的气孔导度（G_s）显著下降,胞间CO₂浓度（C_i）却显著上升。这说明,不同光质处理P_n下降是由非气孔因素引起的。除XY335在蓝膜下外,两玉米品种叶片不同色膜处理下捕获的激子将电子传递到电子传递链中Q_A下游的电子受体的概率（Ψ_o）和以吸收光能为基础的性能指数（PI_ABS）均显著下降,下降的程度表现为绿膜＞红膜＞蓝膜,说明除XY335在蓝膜下表现出品种特异性之外,在不同的色膜处理下PSⅡ的性能均受到明显抑制,且不同处理对PSⅡ反应中心电子受体侧之后的电子传递链性能的抑制作用更大。除XY335在蓝膜下外,两品种不同光质处理叶片供体侧性能（W_k）和受体侧性能（V_j）均显著降低,这说明蓝膜对两品种PSⅡ供体侧和受体侧性能影响较小。而绿膜和红膜均显著降低了两品种PSⅡ供体侧和受体侧的性能,且绿膜下供体侧性能降低幅度大于受体侧,而红膜下反之。XY335和ZD958在不同色膜下PSI的最大氧化还原能力（ΔI/I_o）和两光系统间的协调性（Φ_{（PSⅠ/ PSⅡ）}）均显著下降,表现为红膜＞绿膜＞蓝膜。【结论】阴雨天气下,可见光波段中蓝紫光的减少使得玉米叶片光系统Ⅰ的性能显著下降,造成两光系统间的协调性下降,从而降低了光合电子传递链的性能,最终导致净光合速率的下降。     

玉米高无机磷突变体的选育和特性研究

采用⁶⁰Coγ射线辐射诱变,创造出2个玉米高无机磷突变体lpa-zhong1和lpa-zhong2,研究了其突变的等位性和遗传控制类型,同时对野生型亲本和突变体的种子发芽率、磷组分含量、微量金属元素含量以及农艺性状和产量性状做了初步研究。结果表明,两个突变是等位的,且突变受单隐性基因所控制;与野生型亲本相比,突变造成种子发芽率降低;总磷、无机磷含量极显著增加,植酸含量显著下降;金属元素含量、农艺性状无显著变化;除了百粒重显著下降之外,其他产量性状差异不显著。     

Characterization of low-N responses in maize(Zea mays L.) cultivars with contrasting nitrogen use efficiency in the North China Plain

Over-use of N fertilizer in crop production has resulted in a series of environmental problems in the North China Plain(NCP). Thus, improvement of nitrogen use efficiency(NUE) in summer maize has become an effective strategy for promoting sustainable agriculture in this region. Using twenty maize cultivars, plant dry matter production, N absorption and accumulation, yield formation, and NUE in summer maize were investigated under three N levels in two growing seasons. Based on their yield and yield components, these maize cultivars were categorized into four groups including efficient-efficient(EE) cultivars, high-nitrogen efficient(HNE) cultivars, low-nitrogen efficient(LNE) cultivars and nonefficient-nonefficient(NN) cultivars. In both two seasons, the EE cultivars improved grain yield together with increased plant biomass, and enhanced accumulative amounts as well as higher average grain yields than the other cultivar groups under deficient-N conditions. Significant correlations were observed between yield and kernel numbers(KN), dry matter(DM) amount and N accumulation at both post-silking and maturity stages. DM and N accumulation at late growth stage(i.e., from silking to maturity) contributed largely to the enhanced yield capacity and improved NUE under N-deficient conditions. Compared with the NN cultivars, the EE cultivars also showed increased N assimilation amount(NAA) and N remobilization content(NRC), and elevated N remobilization efficiency(NRE), NUE and nitrogen partial factor productivity(PFPN). Our investigation has revealed N-associated physiological processes and may provide guidance for cultivation and breeding of high yield and NUE summer maize under limited N conditions in the NCP.     

从玉米传粉子房培养出单倍体植株

比较了授粉时间长短和授粉季节对玉米单倍体诱导的影响.结果表明,当授粉时间控制在15-22h,授粉子房均有可能诱导出单倍体植株.春秋季授粉诱导单倍体的效果比夏季好.从26400个子房中共获得281棵再生植株,经根尖压片检查发现其中24棵为单倍体植株,证明利用玉米传粉子房来诱导单倍体植株是可行的.     

玉米热激蛋白70基因对温度胁迫的响应

利用RT-PCR技术从玉米自交系H21叶片中克隆获得一热激蛋白70(HSP70)基因的完整开放阅读框,全长1 737 bp,编码578个氨基酸,命名为ZmHSP70。编码的氨基酸与其他作物比对分析表明,ZmHSP70与高粱中一推测的蛋白(SbHSP70,XP_002465635)同源性最高,达95%,与水稻中一推测的蛋白(OsHSP70,EAY89062)同源性达87%。半定量RT-PCR的结果表明,该基因明显受42℃热激诱导表达,热激2 h其表达量达最大值;4℃冷胁迫也能诱导ZmHSP70表达量增加,冷胁迫4 h,其表达量达最大值。ZmHSP70是一个受温度诱导的热激蛋白。     

玉黄金在玉米上的应用效果分析

在玉米高产栽培过程中,由于种植密度加大,倒伏、秃尖等现象常常出现,制约了玉米产量的提高。本试验研究了玉黄金不同量级、不同施用时期对玉米化控作用。结果表明：玉黄金主要控制基部1-5节节长,使茎秆缩短、粗壮,叶色深绿,株高、穗位降低20-50cm;施用量越高,矮化作用越明显,以300mL·hm^-2为宜;施用时期以玉米展开叶6片时施用为宜。     

沼肥与钾肥配施对玉米叶片抗氧化酶及土壤酶活性的影响

[目的]探究沼肥与钾肥配施对不同基因型玉米叶片保护酶及土壤酶活性的影响,为沼肥与钾肥配施在东北春玉米生产中的应用提供参考.[方法]选用玉米郑单958(紧凑型)和丰禾1号(平展型)为供试材料,采用盆栽方式,设A1(单施沼肥)、A2(沼肥与钾肥配施)和A3(单施钾肥)3个施肥处理,以不施肥为对照(CK).于玉米三叶期后0、8、16和24 d取叶片测定抗氧化酶活性,并于三叶期后0、10、20和30 d取土样测定土壤酶活性.[结果]在不同施肥处理条件下,两供试玉米品种幼苗叶片的超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均随生长天数的增加逐渐升高,各处理提升叶片SOD和POD活性的效果表现为A2>A3>A1>CK.随着玉米幼苗的生长,两供试玉米品种各处理的叶片MDA含量逐渐增加,但与CK相比,各施肥处理整体上可降低叶片MDA含量,且均以A2处理的MDA含量最低.同时,随着施肥时间的推移,玉米根际土壤蔗糖酶、过氧化氢酶和脲酶活性均逐渐增加,不同施肥处理对土壤酶活性的提升效果表现为A2>A3>A1>CK.[结论]适当施用肥料有利于提高东北春玉米幼苗叶片的保护酶活性及玉米根际土壤酶活性,其中以沼肥与钾肥配施的效果最佳.     

农杆菌介导bar基因转化玉米幼胚的研究

通过农杆菌介导法,采用抗除草剂基因(bar)转化3个玉米自交系的幼胚,并对遗传转化影响因素进行优化。结果表明,2,4-D浓度为2 mg·L-1时,胚性愈伤组织诱导率较高;农杆菌最佳的侵染时间为20 min;乙酰丁香酮(AS)明显提高了幼胚的GUS瞬时表达频率,适宜浓度为200μmol·L-1;温和选择方法适于幼胚转化,不定芽诱导培养基、芽伸长培养基和生根培养基中潮霉素的浓度分别为8、6、2 mg.L-1;获得7株PCR检测以及除草剂抗性试验阳性植株。     

玉米细胞质雄性不育性(CMS)的激素调控机制

在以前的研究中我们首次报道了玉米细胞质雄性不育(CMS)花药组织生长素亏损——细胞分裂素盈积现象。这种激素含量的异常在雄性不育性的表达与实现进程中起着重要的调节作用,但现有的研究资料尚不能揭示这种调节作用的机制。本文根据目前有关激素作用机制的几种认识以及玉米 CMS 分子生物学研究成果,结合作用对玉米 CMS 小孢子发育和败育过程中物质代谢系统、能量代谢系统、植物激素系统、生物物理系统、细胞学及超微结构等方面的研究结果,对认识 CMS 机制中有代表性的 Flavell 假说进行了评述,对激素调控玉米 CMS 的可能的分子机制提出了自己的看法。     

高油玉米花粉直感效应与伴侣杂交种的选配研究

以20个优良的普通玉米杂交种为母本,以含油量不同的10个高油杂交种为父本,配制200个杂交当代组合,旨在通过分析杂交当代粒重和油分直感的表现,研究品质性状在杂交当代的表现规律,探讨高油玉米杂交种与普通玉米杂交种配套种植的最佳方式。结果表明,普通玉米杂交种与高油玉米杂交种杂交当代籽粒主要表现为:油分显著增加、百粒重增加不明显;父母本间在这2个性状上互作不显著,但农大62×187、农大62×931和沈单16×961等少数组合杂交当代百粒重有所增加。综合考虑油分、产量、父母本株高、开花期和生育期等性状后,筛选出了适合东北春玉米区和华北夏玉米区种植的不同伴侣杂交种组合,并对伴侣杂交种选育的一些原则进行了讨论。     

玉米ZmNAC1基因的克隆与分析

[目的]NAC(NAM,ATAF1,ATAF2和CUC2)转录因子是植物中特有的具有多种生物学功能的转录调控因子,通过与下游靶基因启动子区域内特异的DNA序列结合,调控下游胁迫应答基因的表达,从而发挥其转录调控功能.本研究从玉米自交系B73中分离得到一个玉米NAC转录因子家族基因ZmNAC1,并对其进行氨基酸序列比对、氨基酸组成和系统进化分析,为进一步研究ZmNAC1基因在非生物胁迫反应中的生物学功能奠定基础.[方法]运用RT-PCR技术克隆基因全长cDNA,应用多种生物信息软件分析基因序列特征:氨基酸组成、保守结构域、跨膜结构域.[结果]结果表明ZmNAC1基因全长962 bp,共编码302个氨基酸;Zm-NAC1蛋白的N-末端具有NAC家族典型的NAM结构域;玉米ZmNAC1与高粱SbSNAC1的氨基酸序列一致性达到80.12％;系统进化分析结果表明ZmNAC1可能在植物抗逆过程中发挥重要功能.     

不同控释肥对夏玉米源库流特性的影响

在大田条件下,以常规施肥为对照,通过测定群体光合速率(CAP)、叶面积指数(LAI)、果穗叶SPAD值.子粒灌浆速率、产量、基部节间伤流强度及穗柄伤流强度等指标,研究了控释肥对夏玉米源库流特性的影响.结果表明,与常规施肥相比,控释肥显著改善了吐丝期以后群体各项生理指标,各控释肥处理的CAP,LAI和果穗叶SPAD值分别提高了5.45%～37.02%,4.61%～26.42%和1.28%～7.51%;穗粒数、穗粒重、千粒重和产量增幅分别为5.56%～20.24%,5.00%～9.50%,3.73%～14.67%和3.38%～13.36%,子粒日增重的平均值增加了14.18%～19.32%;基部节间伤流强度和穗柄伤流强度的增幅分别为2.42%～74.97%和1.41%～116.67%.在本试验条件下,控释肥能明显调节夏玉米源库流特性,其中硫加树脂包膜尿素控释肥的调节效果最好.     

氮肥用量与施用时期及分配比例对夏玉米干物质积累的影响

为合理有效施用氮肥提供依据,以郑单958为试验材料,研究了氮肥用量与施用时期及分配比例对夏玉米干物质积累与分配的影响。研究结果表明:施氮量为10 kg/667 m2时,在苗期施肥比大喇叭口期施肥能获得更大的干物质积累量;大喇叭口期和吐丝期施氮肥有利于玉米生育后期干物质积累;施氮量为20 kg/667 m2,施用时期及分配比例为苗肥30%+大喇叭口肥60%+花粒肥10%的处理,群体干物质积累量和籽粒的干物质积累量最大,最大增长速率、平均增长速率都较高。     

Effects of urea mixed with nitrapyrin on leaf photosynthetic and senescence characteristics of summer maize (Zea mays L.) waterlogged in the field

Waterlogging is one of the major abiotic stresses in agricultural crop production. However, the application of 2-chloro-6-(trichloromethyl) pyridine(nitrapyrin) can effectually mitigate the losses of nitrogen efficiency and grain yield of summer maize induced by waterlogging. In order to explore its role to alleviate waterlogging stress on leaf antioxidative system and photosynthetic characteristics of summer maize, a field experiment was executed to research effects of nitrapyrin application on leaf photosynthetic and senescent characteristics of waterlogged summer maize Denghai 605(DH605) and Zhengdan 958(ZD958). Experimental treatments consisted of waterlogging treatment that was applying only urea(WL), waterlogging treatment that was applying urea mixing with nitrapyrin(WL-N), and no waterlogging treatment that was only applying urea(NWL). Results showed that WL significantly decreased leaf area index(LAI), SPAD, photosynthetic rate(P_n), and protective enzyme activities, accelerated leaf aging, eventually led to a remarkable yield reduction by 38 and 42% for DH605 and ZD958, respectively, compared to NWL. However, the application of nitrapyrin was useful for relieving waterlogging damages on leaf photosynthetic ability. LAI, SPAD and P_n of WL-N for DH605 were 10, 19 and 12–24% higher, and for ZD958 were 12, 23 and 7–25% higher, compared to those of WL, respectively. Moreover, application of nitrapyrin effectually relieved waterlogging losses on antioxidative enzyme activities. Leaf superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) activities of WL-N were averagely increased by 24, 15 and 30%, respectively, while malondialdehyde(MDA) content was averagely decreased by 13%, compared to those of WL. Visibly, nitrapyrin application could improve leaf photosynthetic characteristics and retard leaf aging induced by waterlogging, thereby leading to a yield increase of waterlogged maize.