Effects of Exogenous Injection of Different Sugars on Leaf Photosynthesis, Dry Matter Production and Adenosine 5'-Diphosphate Glucose Pyrophosphorylase (AGPase) Activity in Sweet Potato, Ipomoea batatas (Lam.)

Solutions of sucrose, glucose and fructose were artificially injected into the stems of sweet potato plants. The effects of solution injection on both dry matter production and the activity of adenosine 5'-diphosphate glucose pyrophosphorylase (AGPase) in tuberous roots were investigated and compared. The total weight of carbon (T_C) artificially and photosynthetically supplied to a plant during the treatment period of 40 days was 0.987–1.869 times the weight of photosynthetically assimilated carbon alone. At the final sampling time, the dry matter weight of tuberous roots in the plants injected with sugar solutions showed a 2.73–9.13-fold increase over that of the control plant. The root weight linearly increased with T_C. The activity of AGPase was also enhanced by solution injections, with 27–63 % increases compared to the control, but was not significantly related to T_C. The injection of sugar solutions is concluded to have a dual effect on root production in sweet potato. One effect is that the increased sugar concentration in the plant increases AGPase and sink activities, and the other effect is that the increased carbon supply quantitatively promotes starch synthesis and accumulation in roots.     

甘薯细胞壁蔗糖转化酶基因IbCWIN家族成员鉴定及表达分析

甘薯是重要的粮食、饲料、工业原料作物和新型的生物能源作物,细胞壁蔗糖转化酶是植物源、库组织蔗糖代谢的关键酶,但关于甘薯细胞壁蔗糖转化酶基因IbCWIN家族成员的研究尚未见报道。本研究测定供试品种不同组织部位的蔗糖淀粉含量,利用生物信息学方法对IbCWIN基因家族的理化性质、保守结构域、系统进化关系、启动子作用元件、组织特异性表达模式进行分析。结果表明,甘薯茎中蔗糖含量最高,须根和叶次之,块根最低;块根淀粉含量最高,极显著高于其他部位。甘薯中含有10个IbCWIN基因,编码氨基酸442～1115个,蛋白质分子量范围49.56～124.44kD,等电点为5.0～9.1。分布在8条染色体上,都含有Glyco₃2保守结构域及相同或相似的保守基序motif,属于糖基水解酶基因家族GH32。IbCWIN与木薯MeCWINV同源性高, IbCWIN基因家族启动子区域含有多种类型的顺式作用元件。qRT-PCR结果表明,IbCWIN基因家族在甘薯不同组织中均有表达且有多种表达模式,其中IbCWIN2和IbCWIN9在块根中表达量显著高于其他组织部位。本研究为下一步探索甘薯IbCWI...     

施钾对甘薯根系生长和产量的影响及其生理机制

为探讨施钾调控甘薯根系生长的生理机制,设K0(K_2O:0 kg hm~(-2))、K1(K_2O:75 kg hm~(-2))、K2(K_2O:150 kg hm~(-2))和K3(K_2O:225 kg hm~(-2))4个处理,调查施钾对甘薯生长前期和薯块膨大期根系生长、13C分配量、碳代谢酶活性、光合特性、叶绿素荧光特性、以及产量和产量构成的影响。结果表明,与CK相比,施钾处理2个生长时期光电子传递速率(ETR)提高12.7%~63.6%,净光合速率(Pn)提高7.2%~26.4%,施钾通过提高光合特性加速光合产物积累,为根系生长提供物质基础。同时,施钾有利于光合产物由地上部向地下部运转,地下部13C分配量提高10.6%~66.2%(P0.05)。其次,施钾处理提高了块根中蔗糖合酶、磷酸蔗糖合酶、腺苷二磷酸葡萄糖焦磷酸化酶活性,加速了块根中碳的同化,利于光合产物在块根中的积聚,促进甘薯根系分化与生长。生长前期,施钾处理总根长提高13.6%~22.8%,根平均直径提高11.3%~51.9%,显著提高了不定根向毛细根和块根分化量(P0.05),有利于有效薯块的早期形成,保证有效的单株结薯数。薯块膨大期,施钾处理提高块根生物量,有利于薯块的膨大,提高平均薯块重,最终显著增产。与CK相比,2014年K1、K2和K3处理分别增产15.8%、24.3%和44.7%,2015年分别增产7.9%、13.4%和22.8%。     

甘薯主要数量性状对单株产量的通径分析

用秦薯1号自交后代实生苗为试验材料,试验对甘薯的分枝数(x1)、最长蔓长(x2)、分枝总长(x3)、节间长(x4)、蔓粗(x5) 、叶面积(x6)、单株绿叶重(x7)、藤叶重(x8)、单株薯数(x9)、单薯重(x10)、根冠比(x11)和单株产量(y)12个数量性状进行了测定。通过相关分析、逐步回归和通径分析表明单株绿叶重对单株产量的影响最大;单株薯数和单薯重对单株产量的直接作用较大。高产育种以单株产量为选择目标时,应以单株绿叶重、单株薯数和单薯重的选择为主,结合根冠比、分枝数、叶面积和蔓粗,对这7个性状进行综合考虑和选择。     

Evaluation of Root Sink Ability of Sweet Potato (Ipomoea batatas Lam.) Cultivars on the Basis of Enzymatic Activity in the Starch Synthesis Pathway

Activities of five enzymes, sucrose synthase (SUS), uridine 5'-diphosphate glucose pyrophosphorylase (UDPGPPase), fructose-1,6 bisphosphatase (FBPase), adenosine 5'diphosphate glucose pyrophosphorylase (ADPGPPase) and starch synthase (STS), in the metabolic pathway of starch synthesis, were compared between two sweet potato ( Ipomoea batatas Lam.) cultivars, Koganesengan (C.V.KOG, a recently released high yield cultivar) and Tsurunasigenji (C.V.TSU, an old, local cultivar with poor yield). The measurements were carried out using the root samples (tuberous, thick and fibrous roots) harvested at the fast tubering stage. Of the five enzymes, SUS, ADPGPPase and STS showed high activities in the tuberous root, particularly in that of C.V.KOG, and a similar trend was observed for activities of these enzymes on a protein basis. The increased activity of the three enzymes is considered to be one of the characteristics in a high yield cultivar, allowing the root to function effectively as a starch synthesis and storage organ.     

甘薯地膜覆盖研究进展

甘薯是中国重要的粮食作物之一,地膜覆盖是中国北方薯区甘薯高产的重要措施之一。为此,综述了甘薯地膜覆盖产量提高的机理,主要有：（1）在土壤因素上增加土壤温度,提高土壤湿度、改善土壤的理化性质和加速土壤养分的转化。（2）在产量和形态发育影响方面主要是提前结薯、促进根系发育和防治茎叶徒长。（3）在生理代谢影响方面主要有地膜覆盖提高了叶片叶绿素含量,Rubpase活性、ATP含量和ATP酶活性以及提高了叶片SOD和CAT活性,降低了叶片中MDA含量,提高了叶片光合速率,延迟了叶片衰老;地膜覆盖改变了叶片和块根中的激素含量变化趋势,促进同化物向块根的转运。（4）地膜覆盖提高了甘薯抵抗病虫害以及盐碱胁迫的能力。之后阐述了中国地膜覆盖当前存在的主要问题主要有环境污染问题、减产问题以及农机农艺不配套的问题,最后展望了中国甘薯地膜覆盖将来的发展趋势。     

植物生长调节剂对甘薯产量和激素含量的影响

为了探讨植物生长调节剂对甘薯产量和激素含量的影响,以济薯18、徐薯18和商薯0110为试验材料,在开始进入块根膨大期时(移栽后第35天),叶面喷施矮壮素·DA-6合剂和烯效唑,观察植物生长调节剂对不同生长类型甘薯的产量、光合作用和叶片、块根中的激素含量的影响。结果表明,植物生长调节剂处理促进同化物向根部的转运,提高了块根的产量。其中每hm2喷施1 500 m L矮壮素·DA-6合剂处理显著提高了3个品种的产量,225 g烯效唑处理显著提高了济薯18和徐薯18的产量。调节剂处理对不同类型甘薯光合作用的影响不同,矮壮素·DA-6合剂处理显著提高了徐薯18的光合速率,而对济薯18和商薯0110的光合速率的提高没有达到显著水平,烯效唑处理对甘薯叶片的光合作用没有显著影响。烯效唑处理降低了3个甘薯品种的叶片IAA含量,显著降低了济薯18膨大中期的GA3和叶片ZR含量,降低了徐薯18膨大后期的块根ZR和ABA含量;增加了济薯18和徐薯18膨大中、后期的叶片ABA含量、膨大前、中期块根IAA含量以及整个商薯0110膨大期的块根IAA含量。矮壮素o DA-6合剂处理显著降低了济薯18膨大中期的叶片IAA、膨大后期的块根和叶片ZR含量,降低了徐薯18膨大前期叶片IAA、ZR、ABA、块根ZR含量以及降低了商薯0110膨大前期的叶片GA3和后期的ZR含量;增加了济薯18膨大前期的块根ABA、GA3、叶片ZR、中期的叶片ABA和整个膨大期的块根IAA含量,增加徐薯18膨大前期的叶片ZR、中期的块根GA3和ZR含量、叶片IAA、ABA、后期的块根IAA含量,增加了商薯0110膨大期的块根ZR、ABA、中期的叶片ZR、后期的叶片GA含量。植物生长调节剂处理部分改变了甘薯内源激素的变化动态,促进了地上部同化物向块根的转运,提高了甘薯的块根产量,植物生长调节剂对甘薯光合作用的影响因品种类型而异,并不是影响甘薯块根产量的主要因素。     

改善土壤通气性促进甘薯源库间光合产物运转的原因解析

为了明确土壤通气性对甘薯源库间光合产物运转的调控机制,本研究以淀粉型品种商薯19和济徐23为试验材料,设置疏松、对照和紧实3个处理进行大田试验,研究结果表明,与对照处理相比,疏松处理显著提高2个品种的块根产量和经济系数, 2年平均增幅分别为27.03%～38.74%和6.30%～13.05%,紧实处理则显著降低2个品种的块根产量和经济系数, 2年平均降幅分别为17.87%～15.92%和10.83%～15.63%。功能叶13C标记结果显示,疏松处理显著提高块根中光合产物的输入效率。疏松处理显著提高块根中蔗糖和淀粉含量,显著降低地上部器官中淀粉含量和茎中尤其是茎的中下部中蔗糖含量;紧实处理则显著降低块根中蔗糖和淀粉含量,而显著提高地上部器官蔗糖和淀粉含量,且茎中下部蔗糖含量增幅较大。疏松处理显著降低50～150d茎基部与茎顶部间和茎基部与块根间的蔗糖含量差;紧实处理则显著提高茎基部与茎顶部间和茎基部与块根间的蔗糖含量差,且茎基部与块根间蔗糖含量差的变幅大于茎基部与茎顶部间的蔗糖含量差。相关分析表明,茎基部与块根间、茎基部与茎顶部间蔗糖含量差与块根蔗糖和淀粉含量呈极显著负相关。说明改善土壤通气性可促进茎基部光合产物向块根的运转,提高块根中碳水化合物含量,增加块根产量。     

套作条件下种植密度对紫色甘薯干物质生产的影响

为了研究川中丘陵区旱地套作条件下种植密度对紫色甘薯干物质生产的影响,在与玉米套作条件下,以鲜食型紫色甘薯品种‘南紫薯008’为材料,设置5个种植密度,测定紫色甘薯叶面积指数、群体生长率、群体光合势、干物质积累、产量等指标。结果表明：在套作条件下,随着种植密度的增加,‘南紫薯008’群体叶面积指数有升高的趋势,群体生长率、群体光合势、商品薯率、干物质率、鲜薯产量、淀粉产量均呈先升后降的趋势,而单株结薯数、单株薯鲜重则下降,群体干物质积累量和T/R则随生育期的推进不同密度间表现有所差异。公顷种植密度在3.5×10⁴~4.0×10⁴株时,群体干物质积累量、鲜薯产量、淀粉产量和商品薯率均较高。套作条件下‘南紫薯008’最高鲜薯产量为11816.9 kg/hm²,约为其净作产量的42.6%~53.1%。川中丘陵区旱地套作条件下紫色甘薯适宜的种植密度为3.5×10⁴~4.0×10⁴株/hm²。     

不同施钾量条件下甘薯块根形成的内源激素变化及其与块根数量的关系

In order to explore the changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato root, sweet potato varieties ‘Yanshu 25’ and ‘Beijing 553’ with significant differences in storage root number were used as experimental materials, potassium oxide (K₂O) was used as fertilizer, and four potassium fertilizer gradients of 0 (K0), 120 (K2), 240 (K3), and 360 kg hm^-2 (K4) were set. The effects of different potassium application rates on the contents of endogenous hormones, the activity of related metabolic enzymes, the number of storage root and root evenness in swelling roots of sweet potato during root formation and harvest stage were studied. Compared with the treatment without potassium fertilizer (K0), the application of potassium fertilizer decreased the enzyme activities of indoleacetic acid oxidase (IAAO) and peroxidase (POD), increased the content of indole-3-acetic acid (IAA), increased the content of zeatin riboside (ZR) and decreased the content of gibberellins (GA₃). Potassium application enhanced the activity of primary cambium and promoted the differentiation from adventitious root to storage root by regulating the content of endogenous hormones in swelling roots of sweet potato. Compared with the control, the application of potash fertilizer significantly increased the number and weight of storage roots per plant and root yield of ‘Yanshu 25’ and ‘Beijing 553’. The number of storage roots per plant of ‘Yanshu 25’ and ‘Beijing 553’ increased by 3.16%-25.40% and 3.85%-33.11%, respectively, and the yield increased by 4.22%-17.31% and 3.94%-18.45%, respectively. Compared with the potassium application treatments of the two varieties, the K2 treatment had the highest storage roots number per plant, the highest weight and yield of storage roots, with the best root evenness.     

Reduced Sink Activity in Growing Shoot Tissues of Maize under Salt Stress of the First Phase may be Compensated by Increased PEP‐Carboxylase Activity

The effects of salt stress (100 mm NaCl for 6 days) on growing tissues (shoot apex, growing leaf segments, root tips) of young maize plants (Zea mays L. cv. Pioneer 3906) were investigated in comparison to an unsalinized control, focusing on assimilate supply from source leaves and the activity of sucrolytic enzymes in the sink tissues. The objectives were to test whether (i) phloem unloading in growing tissues is mainly symplastic, (ii) salinity reduces sink activity, determined either as sucrose synthase activity (indicator for the symplastic pathway) or as acid invertase activity (indicator for the apoplastic pathway), and (iii) PEP‐carboxylase activity is increased under salinity to compensate for reduced sink activity. For growing tissues of young maize shoots, it can be assumed that phloem transport of sucrose is mainly driven by symplastic unloading into the sink cells. In maize root tips, both, apoplastic and symplastic pathways, contributed to carbohydrate supply to the sink cells. The activity of acid invertase in growing shoot tissues was very low, and the alkaline invertase contributed less than 10 % to the cytoplasmic sucrolytic activity. Salt stress of the first phase (mainly osmotic stress) caused a significant inhibition of acid invertase activity in the growing leaf segments and in the root tips, which was also true for alkaline invertase activity in the root tips as well as for sucrose synthase activity in root tips and shoot apex. The decrease of sucrose synthase activity in shoot apex might be particularly detrimental for the plant growth, as this tissue with a high cell division rate relied entirely on cytoplasmic enzyme activities. Under salt stress, PEP carboxylase activity was significantly increased in growing leaves and the shoot apex of maize, whereas no significant effect was observed in the root apex. In conclusion, PEP carboxylase can have an anaplerotic function supporting the demand for metabolites in growing shoot tissues of young maize plants under salt stress. In root tips, an additional supply of organic acids to the tricarboxylic acid cycle is probably not needed, as sucrolytic sink activity, which was high even under saline conditions, can meet the demand of the sink cells.     

山东主要农作物籽实及不同器官的热值研究

探讨不同农作物各器官的热值含量,为提高光能利用率和种植结构调整及农艺调控措施提供理论依据。本研究采集山东地区23 种农作物籽实或块根及5 种农作物不同器官,采用氧弹式量热仪测量其热值。农作物籽实或块根热值变化范围在16357.72~29513.69 J/g 之间;油料作物芝麻的热值达到了29513.69 J/g,是水生作物中莲藕（块根）的1.8 倍。不同类别农作物籽实热值的高低顺序为：油料作物＞豆类作物＞禾谷类作物＞水生作物;陆生薯芋类块根热值略高于水生作物莲藕。相同作物不同器官的热值顺序为籽实(20005.80 J/g)＞叶(17452.77 J/g)＞茎鞘(16911.04 J/g);不同作物的籽实和茎鞘热值最高的是花生,叶片热值最高的是甘薯。农作物种类及类别不同,其籽实或块根热值之间差别巨大;相同作物不同器官的热值亦存在较大差异,不同作物相同器官的热值也存在一定差异。     

‘商薯19’静置水培营养液的筛选与内源激素分析

为建立‘商薯19’脱毒苗的水培快繁体系提供依据,通过研究筛选出静置水培条件下‘商薯19’脱毒苗适宜的营养液配方,明确甘薯植株叶片中内源激素种类以及水培对甘薯苗叶片激素的影响。以‘商薯19’脱毒苗为试验材料,分别用循环水生菜营养液、霍格兰营养液和MS等营养液配方,设置不同浓度处理,并以清水培养为对照,研究不同营养液对‘商薯19’脱毒苗生长的影响。利用超高效液相色谱-三重四级杆串联质谱法对水培和土培条件下甘薯激素进行检测。结果表明,静置水培20天,在1/2霍格兰营养液中,甘薯植株最大根长、平均鲜根重、叶绿素相对含量、平均茎长均优于其他营养液处理。对16种植物激素进行检测,结果在甘薯植株体内检测到11种激素,与对照相比,水培植株中脱落酸浓度降低了71.37%,吲哚乙酸浓度降低了51.64%,茉莉酸浓度增加了231.68%。本研究首次对‘商薯19’脱毒苗开展水培研究,筛选出1/2霍格兰营养液为‘商薯19’脱毒苗静置水培最适营养液。对水培条件下甘薯植株内源激素检测,并检测到11种激素,与对照培养相比较,水培条件下甘薯植株的脱落酸和吲哚乙酸含量降低,茉莉酸含量增加,这3种激素浓度变化较大。结果为进一步研究利用甘薯水培技术、建立甘薯植物工厂等提供参考。     

Isolation and characterisation of cDNAs encoding the large and small subunits of ADP-glucose pyrophosphorylase from cassava (Manihot esculenta Crantz)

Screening of a tuber specific cassava cDNA library resulted in the isolation of full length cDNA clones with homology to the genes encoding the small and large subunits of ADP glucose pyrophosphoryalse. Sequence analysis revealed that AGPase B the clone with homology to the small subunit shared 54% homology at amino acid level with the AGPase S clone that is more closely related to the large subunit. Segregation analysis of a cross between the cassava cultivars TMS 30572 and CM 2177-2 revealed that AGPase S is a single copy gene that is localised on the female derived linkage group E of the cassava genetic map. AGPase B is a low copy gene of which one member is localised on the female derived linkage group P. The two genes are expressed in all cassava tissues but AGPase B exhibits a higher steady state mRNA level than AGPase S and is highly expressed in leaf and tuber tissue. The AGPase enzyme activity was much higher in young cassava leaves as compared to older leaves and tubers. Cassava AGPase was activated by 3-PGA and inhibited by up to 90% in the presence of inorganic phosphate (Pi). The tuber enzyme was relatively unaffected by 3PGA but was highly inhibited by Pi. Transformation of potato (Solanum tuberosum) plants with an antisense AGPase B construct resulted in 10 out of 134 antisense AGPase B plants having on average 3.5 times more tubers than the control non transgenic plants. Analysis of these transgenic plants revealed they had greatly reduced levels of AGPase B mRNA, 1.5 to 3 times less starch, and five times higher levels of soluble sugars, sucrose, glucose and fructose, to those found in control plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

结薯数差异显著的甘薯品种生长前期根系特性及根叶糖组分比较

选用结薯数差异显著的甘薯品种商薯19和济徐23,于2013年和2014年分别在大田和盆栽条件下调查生长前期根系生长发育情况,测定根叶糖组分,分析其变化规律及其与单株有效薯块数形成的关系。结果表明,与济徐23相比较,商薯19发根缓苗迅速,整个生长前期均较为侧重吸收根系建成,且秧苗栽后15 d和30 d地上部和整个根系生物量比值(T/TR)相似;而济徐23较早完成不定根的发生(秧苗栽后15 d)和不定根向块根的分化建成(秧苗栽后30 d),封垄期（秧苗栽后45 d）具有较小的地上部和块根生物量比值(T/SR)。2个品种在生长前期根叶中蔗糖、己糖代谢和贮藏糖类多聚物的形成具有显著差异,其中商薯19整个生长前期比济徐23的根系蔗糖/己糖比率显著低,在块根分化建成过程中根叶间具有较高的蔗糖浓度梯度,且根系中存在2种低果聚糖(蔗果三糖和蔗果四糖),秧苗栽后30、45 d叶片淀粉含量显著低;而济徐23在块根分化建成过程中根系仅有蔗果四糖,且与商薯19比,封垄期根系蔗糖/可溶性总糖比率相似而根系蔗糖/淀粉比率显著低。2013年和2014年的大田试验均表明,封垄期商薯19具有显著多的单株有效薯块数和显著高的单株有效薯块鲜重(F=10.71,P=0.0170;F=13.97,P=0.0212),而收获时商薯19具有显著多的单株有效薯块数和显著高的块根产量(F=353.89,P<0.0001;F=88.94,P<0.0001),济徐23具有显著高的平均单薯鲜重(F=10.32,P=0.0124)。     

甘薯四级种薯增产性能研究

以徐薯18为材料,研究了甘薯种薯的增产性能.结果表明,四级种薯的单株干重、净同化率和光合势在整个生育期内均显著高于对照;其干物质分配特点表现为,前期光合产物主要分配给地上部茎叶,中后期光合产物向地下部输送增加,从而奠定了四级种薯高产的物质基础.     

甘薯块根形成和膨大对土壤紧实度的响应机制及与产量的关系

为探讨甘薯块根形成和膨大对土壤紧实度的响应机制及与产量的关系,以源库特征差异显著的食用型甘薯品种"北京553"和"龙薯9号"为试验材料,设置不同的土壤紧实度处理,研究土壤紧实度调控甘薯块根产量的生理生态原因。结果表明,降低土壤紧实度,全生育期耕作层土壤的非毛管孔隙度显著提高。在块根形成期(20～40 d),随土壤紧实度降低,耕作层土壤的最高温度提高、最低温度降低,温度日较差显著提高。在甘薯块根膨大期(45～165 d),与对照相比,疏松处理可以提高块根中蔗糖合酶(SS)和腺苷二磷酸葡萄糖焦磷酸化酶(ADPGPPase)活性,增加淀粉含量;提高块根中干物质积累初始势、干物质积累速率和功能叶13C同化物在块根中的分配比例。在收获时,疏松处理显著提高单薯重和收获指数,北京553和龙薯9号分别增产20.01%～24.25%和21.64%～27.78%。     

高肥力土壤氮钾配施对鲜食型甘薯产量及品质的影响

为了探明高肥力土壤氮钾配施对烟薯25产量和品质的影响,采用二因素三水平完全随机区组试验设计,分别设3个N处理(0,45,90 kg/hm~2)和3个K_2O处理(0,75,150 kg/hm~2),共计9个氮钾组合处理,分别于收获期调查甘薯地上部性状,测定块根干鲜质量、Vc、淀粉、蛋白质、蔗糖、葡萄糖、果糖、Ca、Mg、Fe、Mn、Cu、Zn含量。结果表明:高肥力土壤上施用氮肥可增加甘薯蔓长、茎叶鲜质量、T/R值,并提高甘薯块根内蛋白质、葡萄糖和蔗糖的含量,高肥力土壤上施用氮肥情况下,块根干鲜质量、淀粉和果糖含量有所降低。施用钾肥能显著提高块根干鲜质量、薯干率及淀粉和葡萄糖的含量;促进了甘薯对Mg的吸收,降低了甘薯对Ca的吸收。在氮钾互作条件下,甘薯分枝数、结薯数及Vc、蛋白质、蔗糖、葡萄糖、果糖含量与不施肥处理相比均有所提高;鲜薯产量与氮肥、钾肥的施用存在交互作用,即在不施N、施K_2O 150 kg/hm~2时,甘薯产量达到最高,较不施肥处理增产10 825.5 kg/hm~2,增幅为29.2%。同时在施N 90 kg/hm~2、不施K_2O时,甘薯产量最低,较不施肥处理减产1 435.5 kg/hm~2,降幅为3.9%。因此,在高肥力土壤,应不施或少施氮肥并配施适量钾肥以期获得鲜食型甘薯的高产优质。     

甘薯库源关系及其遗传研究初报

该文选用几种不同类型的甘薯（Ｉｐｏｍｏｅａ ｂａｔａｔａｓ Ｌａｍ），品种相互嫁接。嫁接组合块根的鲜产，干产分别进行方差分析。结果表明，光合源和贮藏库的遗传生理特性对嫁接组合块垠的产量重要作用，库容量大小时甘薯地下部块根产量起重要的决定作用，同时，高库容丰木克服或改善低关类型品种的潜在光合源和潜在生理流，并提高后者的光效能和块根产量，甘薯地下部块根的干物率和薯肉色也是贮藏根固有的遗传生理特性，嫁接     

干湿交替灌溉耦合施氮对水稻根系性状及籽粒库活性的影响

以新稻20为材料进行土培试验,设置浅水层灌溉(0 kPa)、轻度水分胁迫(–20 kPa)和重度水分胁迫(–40 kPa) 3种灌溉方式及0氮(0N, 0 kg hm-2)、中氮(MN, 240 kg hm-2)和高氮(HN, 360 kg hm-2) 3种氮水平,研究不同水氮耦合处理对水稻根长、根冠比、根系伤流、根系有机酸含量、根系玉米素及玉米素核苷与籽粒酶活性的影响。结果表明,灌溉方式与施氮量存在显著的互作效应,轻度水分胁迫增加了主要生育期根长、根系伤流量、根系分泌物中有机酸总量、根系玉米素及玉米素核苷含量,提高籽粒ATP酶、蔗糖合酶及腺苷二磷酸葡萄糖焦磷酸化酶活性,降低穗分化后水稻根冠比,且与MN耦合后产量最高,为本试验最佳的水氮耦合运筹模式;重度水分胁迫则显著降低主要生育期根长、根系伤流量、根系分泌物中有机酸总量、根系玉米素及玉米素核苷含量,降低籽粒ATP酶、蔗糖合酶及腺苷二磷酸葡萄糖焦磷酸化酶活性,增加主要生育期根冠比。水稻籽粒产量与主要生育期水稻根长、根系伤流量、根系分泌物中有机酸总量、根系玉米素及玉米素核苷含量均呈显著或极显著的正相关,而穗分化至成熟期根冠比与水稻产量呈负相关;同时水稻根长、根系伤流量、根系分泌物中有机酸总量、根系玉米素及玉米素核苷含量与籽粒ATP酶、蔗糖合酶及腺苷二磷酸葡萄糖焦磷酸化酶活性呈显著或极显著的正相关。表明通过适宜的肥水调控发挥水氮耦合效应,可以创造良好的根系形态、提高水稻根系代谢能力和籽粒库的生理活性,促进水稻高产。