Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits in indica rice. The results showed that the flag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigated indica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a significant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneficial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be profitable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the significantly negative correlation between leaf thickness and number of panicles per plant counteracted the profitability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not significantly. It has made great progress in the genetic improvement of leaves thickness in inbred indica rice breeding in Guangdong Province, China, since the 1990s.     

Canopy morphological changes and water use efficiency in winter wheat under different irrigation treatments

Water is a key limiting factor in agriculture. Water resource shortages have become a serious threat to global food security. The development of water-saving irrigation techniques based on crop requirements is an important strategy to resolve water scarcity in arid and semi-arid regions. In this study, field experiments with winter wheat were performed at Wuqiao Experiment Station, China Agricultural University in two growing seasons in 2013–2015 to help develop such techniques. Three irrigation treatments were tested: no-irrigation(i.e., no water applied after sowing), limited-irrigation(i.e., 60 mm of water applied at jointing), and sufficient-irrigation(i.e., a total of 180 mm of water applied with 60 mm at turning green, jointing and anthesis stages, respectively). Leaf area index(LAI), light transmittance(LT), leaf angle(LA), transpiration rate(Tr), specific leaf weight, water use efficiency(WUE), and grain yield of winter wheat were measured. The highest WUE of wheat in the irrigated treatments was found under limited-irrigation and grain yield was only reduced by a small amount in this treatment compared to the sufficient irrigation treatment. The LAI and LA of wheat plants was lower under limited irrigation than sufficient irrigation, but canopy LT was greater. Moreover, the specific leaf weight of winter wheat was significantly lower under sufficient than limited irrigation conditions, while the leaf Tr was significantly higher. Correlation analysis showed that the increased LAI was associated with an increase in the leaf Tr, but the specific leaf weight had the opposite relationship with transpiration. Optimum WUE occurred over a reasonable range in leaf Tr. In conclusion, reduced irrigation can optimize wheat canopies and regulate water consumption, with only small reductions in final yield, ultimately leading to higher wheat WUE and water saving in arid and semi-arid regions.     

不同肥料对椭圆叶花锚生长发育的比较研究(英文)

[Objective] The aim was to study the effect of different treatments on development and growth of Halenia ellipitica D.Don.[Method] Three treatments (urea treatment group, diammonium phosphate treatment group and control group) were set in the experiment with 3 replications to detect plant height,root length, leaf number, branch number, flower number and biomass of Halenia ellipitica D.Don. in all experimental groups.[Result] The leaf number,branch number, flower number and output of crude drug of Halenia ellipitica D.Don. in urea treatment group were more than that of Halenia ellipitica D.Don. in diammonium phosphate treatment group and control group,however,the plant height and root length were not significantly different among all groups.[Conclusion] The urea generated better effect on Halenia ellipitica D.Don. cultivation than that produced by diammonium phosphate treatment.     

Effects of post-silking water deficit on the leaf photosynthesis and senescence of waxy maize

Waxy maize is widely cultivated under rainfed conditions and frequently suffers water shortage during the late growth stage. In this study, a pot trial was conducted to examine the effects of post-silking drought on leaf photosynthesis and senescence and its influence on grain yield. Two waxy maize hybrids, Suyunuo 5(SYN5) and Yunuo 7(YN7), were grown under the control and drought(soil moisture content was 70–80% and 50–60%, respectively) conditions after silking in 2016 and 2017. The decrease in yield was 11.1 and 15.4% for YN7 and SYN5, respectively, owing to the decreased grain weight and number. Post-silking dry matter accumulation was reduced by 27.2% in YN7 and 26.3% in SYN5. The contribution rate of pre-silking photoassimilates transferred to grain yield was increased by 15.6% in YN7 and 10.2% in SYN5, respectively. Post-silking drought increased the malondialdehyde content, but decreased the contents of water, soluble protein, chlorophyll, and carotenoid in the leaves. The weakened activities of enzymes involved in photosynthesis(ribulose-1,5-bisphosphate carboxylase and phosphoenolpyruvate carboxylase) and antioxidant system(catalase, superoxide dismutase and peroxidase) reduced the photosynthetic rate(P_n) and accelerated leaf senescence. The correlation results indicated that reduced Pn and catalase activity and increased malondialdehyde content under drought conditions induced the decrease of post-silking photoassimilates deposition, ultimately resulted in the grain yield loss.     

双价抗虫转基因大豆抗苜蓿夜蛾分析(英文)

[Objective] The aim of the research was to analyze the resistance of binary insect-resistant transgenic soybean to Heliothis viriplaca.[Method]In this experiment, resistance analysis of the stabilized binary insect-resistant transgenic soybean to Heliothis viriplaca was conducted in lab and in field conditions.[Result] The results indicated that the leaves of insect-resistant transgenic soybeans T5-150 and T5-195 showed lighter damage than those of non-transgenic soybeans. Meanwhile, the Heliothis viriplaca larvae fed on leaves of these two transgenic soybeans were characterized by less leaf consumption, shortening survival day, slower development and less pupation.[Conclusion]It was concluded that insect-resistance of transgenic soybean to Heliothis viriplaca was increased dramatically and the research provided a reference for selecting binary insect-resistant transgenic soybean to Heliothis viriplaca.     

Characteristics of Rice Plant with Heavy Panicle

Using 15 indica rice varieties with different panicle weight, some ideal plant type characteristics in heavy panicle type of hybrid rice （HPT） and their relation to yield and its components were studied. Results showed that the leaf area index （LAI） of the HPT varieties was lower than that of medium panicle type （MPT） and light panicle type （LPT） varieties, but its decreasing rate of LAI and efficient LAI after heading was slower and had much higher percentage of efficient LAI, specific leaf weight, and ratio of grain to leaf area （cm^2） in comparison with the MPT and the LPT varieties. The length, width, thickness, and area of top three leaves of the HPT varieties were significantly larger than those of the MPT and the LPT varieties, and these components of top three leaves were significantly and positively correlated with the number of spikelets and filled grains, grain weight per panicle, and grain yield. The flag leaf in HPT varieties was erect with sorrow leaf angle, and their leaf angle of 2nd and 3rd leaf from top increased in sequence. The plant height of the HPT varieties was higher than that of the MPT and the LPT varieties, and their leaf site of top three leaves also increased in sequence. Therefore, HPT varieties as an ideal plant type could increase the utilization efficiency of sunlight energy. The ideal plant type characteristics and their adjuncts for the HPT varieties are proposed in this article.     

Responses of Carex lasiocarpa Morphorlogical Characters to Water Regimes at Different Growth Stages

Objective] The morphological characters of C. lasiocarpa were studied to find its morphological responses to different water regimes and growth stretagies through different water experiences. [Method] A seeding transplanting experiment with con-trol ed water levels was set up, and the water level was changed at the middle of the season to compare water influence at the seeding stage and later growing period. C. lasiocarpa height, leaf length, leaf number, rhizome and adventitious roots length were measured at certain time througth the growing season. [Result] Results at the thriving season indicated that C. lasiocarpa height and leaf length in the experiment were similar to that in the field, but leaf number was higher under -5 cm water level and dry-wet alternate conditions than that in the field. At later growth period, height and leaf length under constant flooding (15 cm) was significantly higher than that under other culture conditions, and also that of the field investigation; while the leaf num-ber had a trend as -5 cm water level treatment>constant flooding>dry-wet alternate>field investigation. The height and leaf length were sensitive to seeding stage water effects, and leaf number sensitive to later influences. [Conclusion] Changes of water regimes in the growing season disturbed the growth of C. lasiocarpa, could accelerate or suspend its wilt, and modified the length of life history.     

Reducing maize yield gap by matching plant density and solar radiation

Yield gap exists because the current attained actual grain yield cannot yet achieve the estimated yield potential. Chinese high yield maize belt has a wide span from east to west which results in different solar radiations between different regions and thus different grain yields. We used multi-site experimental data, surveyed farmer yield data, the highest recorded yield data in the literatures, and simulations with Hybrid-Maize Model to assess the yield gap and tried to reduce the yield gap by matching the solar radiation and plant density. The maize belt was divided into five regions from east to west according to distribution of accumulated solar radiation. The results showed that there were more than 5.8 Mg ha~(–1) yield gaps between surveyed farmer yield and the yield potential in different regions of China from east to west, which just achieved less than 65% of the yield potential. By analyzing the multi-site density experimental data, we found that the accumulated solar radiation was significantly correlated to optimum plant density which is the density with the highest yield in the multi-site density experiment(y=0.09895 x–32.49, P0.01), according to which the optimum plant densities in different regions from east to west were calculated. It showed that the optimum plant density could be increased by 60.0, 55.2, 47.3, 84.8, and 59.6% compared to the actual density, the grain yield could be increased by 20.2, 18.3, 10.9, 18.1, and 15.3% through increasing plant density, which could reduce the yield gaps of 33.7, 23.0, 13.4, 17.3, and 10.4% in R(region)-1, R-2, R-3, R-4, and R-5, respectively. This study indicates that matching maize plant density and solar radiation is an effective approach to reduce yield gaps in different regions of China.     

QTL mapping for leaf area in maize(Zea mays L.)under multi-environments

Leaves are the main organs of photosynthesis in green plants. Leaf area plays a vital role in dry matter accumulation and grain yield in maize(Zea mays L.). Thus,investigating the genetic basis of leaf area will aid efforts to breed maize with high yield. In this study,a total of 150F_7 recombinant inbred lines(RILs)derived from a cross between the maize lines Xu 178 and K12 were used to evaluate three ear-leaves area(TELA)under multi-environments. Inclusive composite interval mapping(ICIM)was used to identify quantitative trait loci(QTLs)for TELA under a single environment and estimated breeding value(EBV). A total of eight QTLs were detected under a single environmental condition,and four QTLs were identified for EBV which also can be detected in single environment. This indicated that the EBV-detected QTLs have high genetic stability. A major QTL(qTELA_2-9)located in chromosome bin 2.04/2.05 could be detected in four environments and has a high phenotypic contribution rate(ranging from 10.79 to 16.51%)that making it a good target for molecular breeding. In addition,joint analysis was used to reveal the genetic basis of leaf area in six environments. In total,six QTL×environment interactions and nine epistatic interactions were identified. Our results reveal that the genetic basis of the leaf area is not only mainly determined by additive effects,but also affected by epistatic effects environmental interaction effects.     

Water Consumption and Maize Yield for Alternative Furrow Irrigation in Western Heilongjiang Province

Aiming at less and un-uniform distribution rainfall problems, the serious draught in spring, low crop production and water efficiency in sandy soil area of Heilongjiang Province, the experiment of alternative furrow irrigation was conducted in Dumeng County in 2009. The purpose of the experiment was to find the water consumption law and its influence on maize yield. The results showed that the highest water consumption was during the heading stage and the highest daily consumption of water was during the filling stage. The stimulation effect of alternative furrow irrigation on yield was obvious in the appropriate irrigation level. The best irrigation pattern for the highest yield was as follows： the seedling stage was 325 m3. hm^-2; the jointing stage was 400 m3-hm^-2; and the filling stage was 288 m3- hm-2. The water consumption during each growing period was that the seedling was 38.85 mm; the jointing was 108.11 mm; the heading was 124.39 ram; the filling was 88.96 ram; the milk was 60.21 ram; and the harvesting was 47.89 mm.     

UV-B增强对中高海拔干旱地区玉米生长的影响

1材料与方法 1.1材料 供试玉米品种为“沈单16号”。 1．2试验设计 试验在宁夏永宁农业气象试验站进行,该站位于北纬38°15′、东经106°14′,海拔1116．7m;地处宁夏引黄灌区的中心地带,日照充足、干旱少雨,年降水量200mm左右,雨热同季,降水集中在夏秋;试验田地势平坦,30cm以上为沙壤土,30cm以下为壤土,微碱性,中等肥力,灌溉条件良好。试验时间为2004年和2005年4～9月。     

UV-B增强对中高海拔干旱地区玉米生长的影响

探讨UV-B辐射增强对中高海拔干旱地区玉米的影响,可为正确评估UV-B增强对玉米生长发育的影响程度并据此制定合理的应对措施提供科学依据.采用大田定位试验,利用可升降式紫外灯装置,观测增加不同剂量UV-B辐射情况下玉米的株高、叶面积、绿叶数及产量构成的变化状况.试验结果显示,在中高海拔的干旱地区,UV-B辐射增强使玉米植株矮化、叶面积减小、绿叶数减少和产量降低.叶面积减小的原因是随UV-B辐射增强叶长变短、叶宽变窄,产量降低的原因是产量各构成因素均受到UV-B辐射增强较大不利影响,并且随着UV-B辐射增加量越多,玉米产量降低的幅度越大.     

干旱区绿洲玉米水分生产率影响因素分析——以临泽绿洲为例

[目的]分析干旱区绿洲玉米水分生产率的影响因素.[方法]以黑河中游张掖市临泽县的绿洲灌区为例,根据绿洲灌区主要农作物玉米生长发育期的实际情况,选取了9个影响因素进行灰色关联分析.[结果]灰色关联度大小排序结果显示,1995～ 2009年影响玉米水分生产率的前5位主要因素依次是化肥施用量＞劳动力投入＞生产用种子＞地膜使用量＞农药施用量.说明干旱区绿洲玉米水分生产率受可控因素的影响明显大于不可控因素.[结论]在水资源限制的前提下,未来合理高效配置农业生产中可控因素的投入,应是干旱区绿洲玉米水分生产率提高的主要对策.     

增强UV-B辐射对芒果成年树光合作用及其产量与常规品质的影响

[目的]了解增强UV-B辐射对芒果成年树光合作用、产量和常规品质的影响,为制定芒果抗增强UV-B辐射栽培技术提供理论依据.[方法]以台农一号芒果成年树为试验材料,设6个增强UV-B辐射(采用UV-B紫外灯进行照射)处理(20、40、80、120、160和200 W),以自然光照射为对照(CK),测定分析各处理成熟叶片的光合指标、果实产量和常规品质.[结果]增强UV-B辐射处理芒果成熟叶片的叶绿素含量、类胡萝卜素含量、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)总体上均随增强UV-B辐射剂量的增加而下降,且表现增强UV-B辐射积累效应和剂量效应.160和200 W处理芒果的株产低于CK,其余增强UV-B辐射处理的株产与CK相当;可溶性糖含量、果实糖酸比和维生素C(Vc)含量总体上随增强UV-B辐射剂量的增加而降低,且除第2造果的200 W处理外其他处理果实的糖酸比、80 W以上处理的可溶性糖含量及120 W以上处理的Vc含量均显著低于CK(P<0.5,下同);可滴定酸含量总体上随增强UV-B辐射剂量的增加而升高,其中80 W以上处理显著高于CK.[结论]芒果成年树受增强UV-B辐射后其叶片光合作用受到抑制,果实可溶性糖含量、糖酸比和Vc含量降低,且具有增强UV-B辐射积累效应和剂量效应,引起果实减产和品质变劣.     

UV-B辐射对葡萄叶片光合色素和类黄酮含量的影响

[目的]研究UV-B辐射对葡萄叶片光合色素和类黄酮含量的影响,以期为研究UV-B辐射增强对葡萄光合作用的影响提供依据。[方法]试验在室外条件下,以酿酒葡萄＂赤霞珠＂（Cabernet Sauvignon）为材料,通过增加不同强度的UV-B辐射,测量葡萄叶片光合色素和类黄酮含量的影响。[结果]低辐射（T1）处理下,叶绿素a、叶绿素b、总叶绿素、类胡萝卜素含量平均值分别比对照增加了5%、2%、4%、3%;高辐射（T2）处理下,叶绿素a、叶绿素b、总叶绿素、类胡萝卜素含量分别比对照增加了11%、9%、10%、7%,其中,叶绿素a差异达显著水平。类黄酮的含量也随着UV-B辐射天数延长而显著增加,T1、T2平均值分别比对照增加了13%、9%。[结论]葡萄对UV-B辐射增强具有较强的适应性,一定范围内适当增加UV-B辐射可能不会对葡萄叶片的光合作用产生不利的影响。     

UV-B对不同烤烟品种质体色素的影响

[目的]研究不同UV-B强度对烤烟质体色素含量的影响,探讨UV-B对烤烟品质的影响机理。[方法]采用5个不同的UV-B辐射强度,对3个品种红花大金元、K326和云烟87,旺长期烟株进行辐射处理,分别采集处理7、14、21和28 d后的新鲜叶片测定叶绿素和类胡萝卜素含量。[结果]UV-B对不同烤烟品种质体色素含量的影响随UV-B强度和照射时间而变化,且不同品种之间的差异较大。减弱30%UV-B处理28 d后,导致K326和云烟87中部叶质体色素含量升高,但对红花大金元的影响则不显著。而增加1.5 h的UV-B照射,28 d后3个品种的质体色素含量均降低。而增强3.0 h的UV-B照射处理7 d后,红花大金元和K326质体色素含量升高,云烟87的叶绿素含量降低,类胡萝卜素含量升高。[结论]该研究可以为提高烟叶品质和品种的合理布局提供重要的理论依据。     

短时间不同剂量UV-B辐射处理对冬小麦幼苗生理指标的影响

[目的]研究短时间不同剂量UV—B辐射对冬小麦幼苗叶片生理指标的影响,为进一步研究植物应答短时间紫外线照射机理提供参考。[方法]以冬小麦为试验材料,采用15和30μW／cm^2的uV—B照射强度对冬小麦幼苗进行短时间照射处理,并测定色素含量、光合速率等生理指标。[结果]UV—B处理导致叶绿素、可溶性蛋白含量以及含水量都降低,且存在剂量效应,30μW／cm^2处理的降幅大于15μW／cm^2;UV—B辐射处理对类胡萝卜紊含量的影响与花青素相同,均表现为先下降后上升的趋势,2种剂量间差异不大;2种剂量的UV—B处理均抑制了PSⅡ的电子传递,尤其是处理2h的抑制作用最大,4、6和8h的抑制作用有所缓解,且存在剂量效应;2种剂量的UV-B辐射均抑制了叶片的光合速率。随着照射时间的延长抑制效应加大;高剂量UV—B处理对膜系统的损伤较大,低剂量UV—B处理结果不明显。[结论]短时间UV—B辐射处理对冬小麦幼苗叶片的影响具有剂量效应,高剂量比低剂量的作用效果大。且随着处理时间的延长,受害程度有所减轻,该结果与长时间UV—B照射的结果不同。     

UV-B辐射增强对棉花叶片显微结构的影响

[目的]研究在大田栽培和自然光照条件下,人工模拟紫外辐射(UV-B,280～320 nm)增加对棉花叶片显微结构、品质和产量的影响.[方法]通过人工增加对棉花UV-B辐射,设置4个处理,每个处理的辐射剂量分别为0 w/m2 (R0)、0.5(R1)、1(R2)和1.5 w/m2(R3).在处理的第45 d时测定棉花叶片伤害状况,叶面积、叶绿素含量和棉花叶片显微结构.[结果]随着UV-B辐射增强, 棉花叶片可见伤害症状越来越严重;叶面积逐渐减小,各个处理之间均达到了极显著差异(P<0.01);棉花叶片叶绿素a、叶绿素b和总叶绿素含量呈现先升后降的趋势;经过主脉的叶片厚度、木质部和韧皮部厚度变化趋势是R1>R0>R2>R3,上表皮、下表皮、栅栏组织和海绵组织厚度大小为R1>R2>R0>R3.[结论]UV-B辐射增强对棉花造成一定程度的伤害,当辐射剂量超过棉花植株体内一定的阈值之后,伤害程度就越大.     

旱地保护性耕作对土壤呼吸和夏玉米产量的影响

[目的]研究旱地保护性耕作对土壤呼吸和夏玉米(Zea mays L.)产量的影响,为西北旱作夏玉米田保护性耕作提供技术依据。[方法]设置传统耕作(CK)、还田免耕(NTS)、还田深松(CTS)和还田旋耕(RTS)4个耕作方式。[结果]夏玉米田CO2平均排放速率表现为RTS>CK>NTS>CTS,CTS处理能够较传统翻耕极显著地提高有效穗数和穗粒数(P<0.01)。与CK相比,CTS、NTS和RTS处理能提高产量24.44%、6.96%和9.17%,但差异未达到显著水平。[结论]土壤深松与秸秆还田相结合是西北地区旱地夏玉米较适宜的耕作方式。     

增强UV-B辐射和干旱对不同品种春小麦生长、产量和生物量的影响

 【目的】通过研究增强UV-B辐射和干旱胁迫对不同品种春小麦生长、产量和生物量的影响,为筛选高产、抗旱、抗UV-B辐射春小麦新品种提供依据。【方法】设置干旱、增强UV-B辐射以及二者复合处理处理西北干旱区三个不同的主栽春小麦品种,检测和分析旗叶面积、叶片厚度、叶面积指数、生物量、根冠比、产量和收获指数等生理指标。【结果】增强UV-B辐射可抑制春小麦分蘖,而适度干旱胁迫可促进春小麦分蘖;增强UV-B辐射和干旱胁迫条件下,定西-24、陇春-8139、和尚头生物量分别降低22%,21%和15%,,平均降低20%;复合作用对产量和生物量的影响与增强UV-B辐射和干旱胁迫分别处理相比,没有明显的减少;干旱胁迫较增强UV-B辐射和二者的复合作用对收获指数和产量的负面影响稍小;干旱胁迫使和尚头和定西-24收获指数增加10%,陇春-8139增加23%;而增强UV-B辐射下和尚头的收获指数下降10%,定西-24和陇春-8139的收获指数均提高10%。说明不同品种春小麦在干旱胁迫、增强UV-B辐射以及二者复合作用下,光合产物向生殖器官的分配比例不同。【结论】春小麦对干旱和增强UV-B辐射胁迫的响应存在品种间的差异性;3个品种对干旱胁迫和增强UV-B辐射的响应趋势基本一致; 干旱胁迫和增强UV-B辐射对3个品种生长都具有抑制效应,但品种间存在一定的敏感性差异。在干旱胁迫和增强UV-B辐射作用下,陇春-8139较定西-24、和尚头分蘖少,但千粒重、收获指数和产量最高。因此,陇春-8139在抗旱、抗UV-B辐射和增产方面比其他2个品种具有更大的优势。