Root morphology in response to nitrogen supply in mid-season indica rice cultivars released in different decades

正Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differences in growth period and pattern between the old and new rice cultivars,it is difficult to clarify how genetic improvements contribute to root growth in rice.For example,for a solution culture system,Wu et al.suggested that total root length increased with increasing year of release for maize hybrids,while shoot dry weight,     

Photosynthesis and water relations of almond tree cultivars grafted on two rootstocks

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year.     

Photosynthesis and water relations of almond tree cultivars grafted on two rootstocks

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year. This revised version was published online in June 2006 with corrections to the Cover Date.     

Improving cucumber photosynthetic capacity under NaCl stress by grafting onto two salt-tolerant pumpkin rootstocks

Cucumber plants were either self-grafted or grafted onto two salt-tolerant pumpkin rootstocks Chaojiquanwang (Cucurbita moschata Duch), and Figleaf Gourd (Cucurbita ficifolia Bouche). Plants were grown hydroponically in 0, 30, 60, or 90 mM NaCl for 16 d in greenhouse. Salinity induced a smaller decrease in plant shoot dry mass, leaf area, net photosynthetic rate, and stomatal conductance in the two rootstock-grafted plants compared to the self-grafted plants. In addition, a significant increase in intercellular CO₂ concentration, as well as a significant decrease in the initial and total ribulose-1,5-bisphosphate carboxylase/oxygenase activities were observed only in the self-grafted plants under 90 mM NaCl treatment. These results suggest that the use of salt tolerant rootstock can improve cucumber photosynthetic capacity under salt stress through both stomatal and non-stomatal pathways.     

Organelle DNA polymorphism in apple cultivars and rootstocks

Summary Restriction fragment length polymorphisms (RFLPs) have been used to detect chloroplast (cp) and mitochondrial (mt) DNA variation among 18 apple cultivars and three rootstocks. The distribution of RFLP patterns allowed the assignment of these genotypes into three groups of cytoplasmic relatedness. Our results also demonstrate maternal inheritance of cp- and mtDNAs in apple. Thus, the organelle DNA assay provides a convenient and reliable method to assess cytoplasmic diversity within the apple germ-plasm collection and to trace the maternal lineages involved in the evolution of apple.     

Effect of rootstocks on floral nectar composition in apple cultivars

 Insect attraction of flowers in apple cultivars is an essential question from the viewpoint of fruit yield, since apple flowers are autosterile and entomogamous. Therefore, it is important to study the two most significant factors of primary attraction, pollen and nectar production. The composition of nectar in apple cultivars on different rootstocks was investigated, putting an emphasis on sugar components. It was stated that the composition of nectar and the ratio of mono- and disaccharides was almost identical and constant in trees on rootstock M.4, whereas on other rootstocks the effects of the season were more pronounced. In triploid cultivars on rootstocks M.9 and M.26 nectar can be characterised by the dominance of sucrose. Relationship was found between free fertilisation rate of cultivars and sugar amount of nectar. In triploid cultivars nectar sugar content was usually lower than in diploid ones, and reached the bee visitation threshold only in some years, influenced also by the effect of rootstocks. Received August 27, 2002; accepted November 16, 2002 Published online: June 2, 2003     

Seasonal variations in apparent photosynthesis among plant stands of different soybean cultivars

The CO₂- and H₂O-exchange rates between soybean canopies and the atmosphere were measured in three mobile chambers (4 m³). Each chamber stopped at 8 or 9 plots (3.1-m² ground area) every 25 min. Diurnal and seasonal CO₂-exchange rates (CER) of 13 soybean (Glycine max (L.) Merr.) cultivars are summarized here. The oldest two cultivars, released in 1927 and 1932, had the lowest CER values. The CER usually decreased in the afternoon (23.4 vs 27.8 mol CO₂ m^-2 s^-1 at 1.6 mmol photons m^-2 s^-1), except shortly after rainfall. During a drought, these reductions occurred earlier in the day and were more pronounced. We present evidence for a nonstomatal component of the CO₂ flux-reaction system causing CER reductions during a water stress. Daytime CER values were not correlated with temperature (24–34° C), but nighttime values were (15–25° C, r=0.85,* n=41).     

Photosynthesis and yield traits in different soybean lines in response to salt stress

To evaluate utility of different salt-tolerant lines, three soybean lines with different resistance to salt were planted in the field under control and salt-stress conditions for two years. The results showed that net photosynthetic rate (P_N) was significantly different among lines at the anthesis stage and decreased on average by 13.6-34.1% under conditions of salt stress. The stomatal conductance was a primary limiting factor for the reduction of P_N under salt stress. Meanwhile, the grain yield (GY) decreased on average by 14.0-35.3% among lines under salt stress. The salt-tolerant lines S111-9 and S113-6 showed higher P_N and GY under salt stress in comparison with the salt-sensitive cultivar Melrose. Regression analysis indicated that there was extremely significantly positive correlation between GY and P_N under field conditions. Therefore, P_N might be used as a physiological index for field resistance of soybean to salt stress.     

Salt tolerance of soybean cultivars

Soybean (Glycine max) cv. Clark tolerated NaCl salinity up to osmotic potential in soil -1800 kPa, cv. Forest to -1500 kPa and cv. Kint to -1200 kPa. The tolerance of cvs. Clark and Forest was found to be related to the accumulation of soluble proteins, amino acids, proline, K and Ca. The sensitivity of cv. Kint was found to be associated with decrease in water, saccharide, protein, K and Ca contents. The leaf osmotic potential decreased in cvs. Clark and Forest while remained unchanged in cv. Kint. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparative analysis of embryogenic potential of soybean cultivars zoned in different eco-geographic world regions

Embryogenic potential of 19 soybean cultivars originated from different eco-geographic regions (Europe, China, America and Far East) has been established and analyzed. Cultivars TSZ-14, Amurskaja-111, Gribovskaja mestnaja were emphasized as highly embryogenic genotypes. Cultivar Mantherova biela vel. revealed the highest embryogenic potential (80%). The comparison of embryogenic potential of the Ukrainian cultivars with given data indicated various parameters which could affect the induction of soybean somatic embryogenesis. It had also been supposed that cultivars from the Far East and Europe could have the potential for further screening of new highly embryogenic genotypes. The data obtained enlarge the data base pool of the soybean somatic embryogenesis research and enable using the most appropriate cultivars for further genetic improvement.     

Chemoenzymatical grafting of acrylamide onto lignin

Laccase (E.C.1.10.3.2.) from white-rot basidiomycete Trametes versicolor and dioxane peroxides were essential in the copolymerization of acrylamide and a derivative with lignin in a dioxane-H(2)O (7:3) mixture. Both a solubility test and an elemental analysis of the eluted and separated fractions provided evidence of grafting. Gel permeation chromatography on Sephadex G-100 showed that the side chain and the lignin backbone migrate as one unit through the column. Copolymers obtained were characterized by UV-VIS-spectroscopy as well as FT-IR, and 13C-CPMAS-NMR spectroscopy. Freeze-dried copolymers of lignin and acrylamide appeared as homogeneous fibril-like particulate. The mechanism of the enzymatical grafting is discussed.     

Improving melon and cucumber photosynthetic activity, mineral composition, and growth performance under salinity stress by grafting onto Cucurbita hybrid rootstocks

The aim of the current work was to determine whether grafting could improve salinity tolerance of melon and cucumber, and whether possible induction of tolerance to salt stress was associated with the protection of the photosynthetic apparatus. Two greenhouse experiments were carried out to determine gas exchange, mineral composition, growth and yield of melon (Cucumis melo L. cv. Cyrano) and cucumber (Cucumis sativus L. cv. Akito) plants, either ungrafted or grafted onto the Cucurbita hybrid rootstocks (Cucurbita maxima Duch. × Cucurbita moschata Duch.), ??P360??, and ??PS1313??, respectively. Plants were grown hydroponically and supplied with two nutrient solutions ?? a nonsalinized control and a salinized solution which contained 40 mmol L^?1 of NaCl. Salinity induced a smaller decrease in leaf area index (LAI), in grafted-compared to ungrafted plants. Similarly, the P _N and g _s reduction in NaCl treatment compared to control were significantly lower in grafted plants (34% and 34%, respectively, for melon and 14% and 15.5%, respectively, for cucumber) compared to ungrafted plants (42% and 40%, respectively, for melon and 30% and 21%, respectively, for cucumber). In all grafting combinations, negative correlations were recorded between Na⁺ and Cl^? in the leaf tissue and P _N. Grafting reduced concentrations of sodium, but not chloride, in leaves. Under saline conditions a smaller reduction in melon and cucumber shoot biomass dry mass and fruit yield were recorded, with positive correlations between shoot biomass, yield and P _N. These results suggest that the use of salt tolerant Cucurbita rootstock can improve melon and cucumber photosynthetic capacity under salt stress and consequently crop performance.     

Molecular species of glycinin in some soybean cultivars

A(4) polypeptide-containing (Shirotsurunoko and York) and A(4) polypeptide-lacking (Raiden and Suzuyutaka) soybean cultivars were used to investigate the heterogeneity of glycinin molecular species. Purification of glycinin by DEAE-Toyopearl column chromatography afforded molecular species eluting before the glycinin fraction. Analysis of this fraction by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and sucrose density gradient centrifugation indicated that this protein consisted of A(1) and A(2) polypeptides. The A(4)-containing soybean cultivars contained less of this protein than the A(4)-lacking soybean cultivars, as exhibited by the size of the early peak appearing during column chromatography. Alkaline PAGE and N-terminal amino acid sequence analysis confirmed that the A(1)- and A(2)-rich molecular species in the A(4) polypeptide-lacking cultivars consisted of the A(1a) and A(2) polypeptides. Estimation of the molecular mass by gel permeation chromatography and multi-angle laser light scattering (GPC-MALLS) indicated that the A(1a)- and A(2)-rich molecular species were similar to a monomer of glycinin.     

不同类型茄对镉的富集及嫁接对镉富集特性的影响

以普通茄(Solanum melongena,绿健)和野生茄(S.torvum,托鲁巴姆)为实验材料,通过对嫁接处理前后7叶龄植株开展7d含Cd水培实验(Cd浓度为0.1 mg· L-1),研究Cd在不同类型茄体内的富集特征以及嫁接对茄体内Cd运输途径和富集特性的影响.结果表明:绿健对Cd的富集能力强于托鲁巴姆.不同部位器官中Cd的分布特征为根＞叶＞茎,其中植株吸收的Cd 80.0％左右富集于根部;不同部位叶片,Cd优先富集于植株顶端幼叶中.嫁接使得Cd在茄地上部的富集量明显减少,接穗Cd的富集量均显著低于砧木:以绿健为对照,正向嫁接减少了48.4％,反向嫁接减少了34.2％,托鲁巴姆自嫁接减少了88.5％;以托鲁巴姆为对照,仅自嫁接地上部Cd富集量减少了58.0％.嫁接减少Cd在茄体内富集的原因可能是嫁接使接穗与砧木植物韧皮部结构产生了差异,由此推断Cd在茄体内的长距离运输过程中韧皮部起到了关键作用.     

Constituents of soybean cultivars differing in insect resistance

Leaf samples of two insect-resistant plant introductions (PI 227687 and PI 229358) and two susceptible (Ransom and Coker Hampton 266A) cultivars of soybeans, Glycine max, were analyzed at different growth stages for their contents of total nitrogen, carbohydrates, organic acids, and sterols. The two susceptible cultivars accumulated more total nitrogen and at a faster rate than did the two resistant plant introductions. At pod-filling, the two resistant cultivars had equivalent soluble carbohydrates and 33% more than the susceptible cultivars. The quantity of organic acids was essentially the same for the two susceptible cultivars. The resistant cultivars had distinctly different quantities from each other as well as from the susceptible cultivars. The quantity of total sterol of these soybean cultivars varied during the growth of the plant. The resistant cultivars accumulated sterol faster and by pod-filling contained from 20 to 50% more sterol than did the susceptible cultivars.     

Demographic parameters of Spodoptera exigua (Lepidoptera: Noctuidae) on different soybean cultivars

Life table, reproduction, and population growth parameters of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), were determined on nine soybean (Glycine max L.) cultivars ('032', '033', 'Hill', 'M4', 'M7', 'M9', 'M11', 'TMS', and 'Zane') at 25°C. The age-specific survival rate of eggs and immature stages was higher on 033 in comparison with other cultivars. The gross fecundity rate ranged from 911 on M9 to 1,296 on Zane, but the differences were not statistically significant. The net fecundity rate was significantly higher on 033 (1,082 eggs per female) than on other cultivars. The gross fertility rate significantly differed on tested cultivars, and was the highest on Zane (1,257 eggs per female) and lowest on Hill (813 eggs per female). The net fertility rate varied from 532 on M11 to 1,082 eggs per female on 033. Both daily number of eggs and daily number of fertile eggs laid per female varied significantly among the different cultivars, and were the highest on TMS (90 for both parameter) and lowest on M7 (47 and 43), respectively. The values of net reproductive rate, intrinsic rate of increase, and finite rate of increase were significantly higher on 033. The shortest generation time (23 d), shortest doubling time (1.66 d), and highest percentage of female offspring (56%) also were obtained on 033. According to population growth parameters, 033 and Hill partially were susceptible and resistant, respectively, to S. exigua. The results of this study provide direction to design a more comprehensive integrated pest management program for this pest.     

Effects of transgenic rootstocks on growth and development of non-transgenic scion cultivars in apple

Although cultivation of genetic modified (GM) annual crops has been steadily increasing in the recent 10 years, the commercial cultivation of GM fruit tree is still very limited and reports of field trials on GM fruit trees are rare. This is probably because development and evaluation of GM fruit trees require a long period of time due to long life cycles of trees. In this study, we report results from a field trial on three rolB transgenic dwarfing apple rootstocks of M26 and M9 together with non-transgenic controls grafted with five non-transgenic scion cultivars. We intended to investigate the effects of transgenic rootstock on non-transgenic scion cultivars under natural conditions as well as to evaluate the potential value of using the rolB gene to modify difficult-to-root rootstocks of fruit trees. The results showed that all rolB transgenic rootstocks significantly reduced vegetative growth including tree height regardless of scion cultivar, compared with the non-transgenic rootstocks. Flowering and fruiting were also decreased for cultivars grown on the transgenic rootstocks in most cases, but the fruit quality was not clearly affected by the transgenic rootstocks. Cutting experiment and RT-PCR analysis showed that the rolB gene was stably expressed under field conditions. PCR and RT-PCR analyses displayed that the rolB gene or its mRNA were not detectable in the scion cultivars, indicating no translocation of the transgene or its mRNA from rootstock to scion. Our results suggest that rolB modified rootstocks should be used in combination with vigorous scion cultivars in order to obtain sufficient vegetative growth and good yield. Alternatively, the rolB gene could be used to dwarf vigorous rootstocks of fruit trees or produce bonzai plants as it can significantly reduce the vegetative growth of plants.     

Photosynthesis in flashing light in soybean leaves grown in different conditions. II. Lightfleck utilization efficiency

Leaves of soybean plants grown in contrasting light and nutrient availability conditions were exposed to constant and to flashing light regimes with lightflecks of different frequencies, durations and photon flux density (PFD). The lightfleck characteristics were selected to be representative of the range of variation found for sunflecks in a soybean canopy. CO₂ fixation rates were measured using a fast-response gas-exchange apparatus. The net CO₂ fixation due to 1-s-duration lightflecks was 1·3 times higher than predicted from steady-state measurements in constant light at the lightfleck and background PFD. This lightfleck utilization efficiency (LUE) was somewhat higher at a high than at a low frequency of one second lightflecks. LUE in flashing light with very short lightflecks (0·2s) and single 1 s lightflecks was as high as 2, but decreased sharply with increasing duration of lightflecks. This decrease occurred because CO₂ fixation rates during lightflecks were constrained by carbon metabolism and induction limitations, and because the contribution of post-illumination CO₂ fixation to total CO₂ fixation decreased with increased duration of lightflecks. LUE increased with increased PFD during the lightflecks, particularly in leaves from plants grown in high-light, high-nutrient conditions. Saturation PFDs were much higher in flashing light than in constant light. Only small differences in LUE were apparent between leaves from the three growth conditions.     

Photosynthesis and photorespiration in two cultivars of cotton under salt stress

Different NaCl concentrations in a nutrient medium ofGossypium hirsutum L. induced a different decrease in the rates of photosynthesis and photorespiration in two cultivars.     

Cell wall glycoproteins of Candida albicans as released by different methods

Different methods of extraction frequently used in other studies were used to release glycoproteins from both intact cells and isolated cell walls of yeast and hyphal forms of Candida albicans. Extracts were obtained from whole cells by treatment (i) with 2-mercaptoethanol (beta ME) at pH 8.6 and 37 C degrees and (ii) with zymolyase after treatment with beta ME. Extracts were obtained from isolated and washed cell walls (i) by boiling with beta ME and sodium dodecyl sulphate (SDS), (ii) by boiling with SDS and (iii) by treatment with zymolyase after SDS. The extracts were separated by SDS-polyacrylamide gel electrophoresis and analysed by Western blotting with four reagents. Analysis with concanavalin A (ConA) revealed different glycoprotein populations depending on the treatment. Three possible germ-tube-specific constituents were observed; and 80 kDa component released by beta ME from both intact cells and cell walls, and 47 kDa and 43 kDa moieties released by zymolyase only from intact cells. MAb 4C12, specific for the protein portion of a large germ tube constituent, recognized polydisperse material which just entered the gel in beta ME extracts and in the region extending up from 200 kDa to near the top of the gel in zymolyase extracts. MAb 24.17, specific for a carbohydrate determinant of yeast phase cells, reacted with disperse material in the region from the top of the gel to one-third to two-thirds the distance to the 220 kDa mass marker. Antiserum specific for the serotype A determinant of mannan reacted with large disperse component(s) migrating in the region from the top of the gel to about two-thirds the distance to the 220 kDa mass marker and with a 180 kDa component. The components recognized by MAb 4C12, but not those recognised by MAb 24.17 and serotype A antiserum, were effected by treatment with endo-beta-N-acetylglucosamidase H. The various analyses revealed that the method of extraction affected the composition and size of the constituents recognized by the reagents.