叶龄调控下水肥耦合对寒地水稻生物学特征及水肥利用效率的影响

【目的】旨在通过优化水稻生育进程的水肥供给来促进水稻的生长发育。【方法】大田试验于2016—2017年在黑龙江省八五二农场进行,以垦稻24 (主茎叶片数为12) 为材料,采用2种灌溉模式和2种施肥模式的正交试验设计：叶龄灌溉模式 (LI) 与常规灌溉模式 (RI),叶龄调控侧深施肥模式 (SF) 与常规施肥模式 (RF)。【结果】LI+SF模式对水稻形态特征、光合特性、水肥利用效率及产量具有显著影响(P<0.05)。与RI+RF相比,LI+SF模式使叶面积指数、单株不定根数、总根长、总根表面积及总体积显著提高了21.2%、22.7%、20.8%、45.2%和17.8%,灌浆期水稻光合速率、净光合速率、叶绿素含量及气孔导度显著提高了17.4%、18.4%、26.8%和40.1%,水稻结实率、千粒重和理论产量显著提高了6.3%、2.4%和28.2%,实收产量平均增加5.2%,纯收入增加13.2%,氮肥农学利用率、籽粒吸氮量、产谷利用效率、氮肥偏生产力及氮收获指数被显著提高了11.1%、6.9%、5.8%、13.6%和8.0%。LI模式可以节约灌溉水用量1 000 t/hm²。RI+SF对水稻植株形态、光合特性、生物学产量和水肥利用率具有一定的促进作用,实收产量平均增加2.3%,没有充分发挥水肥耦合作用。【结论】LI+SF模式为本研究最佳的精准灌溉施肥模式,也是适合在我国北方推广的寒地水稻节水、节肥、丰产技术模式。     

Effects of Irrigation and Fertilization Coupling on Biological Characteristics,Water and Nitrogen Use Efficiencies of Rice in Cold Regions Under Leaf Age Regulation

【Objective】The objective is to improve the growth and development of rice by optimizing water and fertilizer supply in rice growing duration.【Method】A field experiment of fertilization and irrigation under leaf age regulation was conducted in 2016 and 2017 at 852 Farm in Heilongjiang Province. Rice variety Kendao 24 was used as material under two irrigation modes (leaf age irrigation mode, LI; conventional irrigation mode, RI) and two fertilization modes (leaf age regulation side deep fertilization mode, SF; conventional fertilization mode, RF).【Result】Rice morphological traits, photosynthetic characteristics, water and fertilizer use efficiency and grain yield were significantly affected by LI+SF (P< 0.05). Compared with RI + RF, LI+SF significantly increased leaf area index, adventitious root number per plant, total root length, total root surface area and total root volume by 21.2%, 22.7%, 20.8%, 45.2% and 17.8%, respectively. Photosynthetic rate, net photosynthetic rate, chlorophyll contents and stomatal conductance were significantly increased by 17.4%, 18.4%, 26.8% and 40.1%, respectively. Seed setting rate, 1000-grain weight and theoretical yield were significantly increased by 6.3%, 2.4% and 28.2%, respectively. Average yield was increased by 5.2%, and net income was increased by 13.21%. Agronomic efficiency of nitrogen fertilizer, grain nitrogen uptake, grain yield and utilization efficiency, partial productivity of nitrogen fertilizer and nitrogen harvest index were significantly increased by 11.1%, 6.9%, 5.8%, 13.6% and 8.0%, respectively. In addition, 1 000 t/hm2 irrigation water can be saved by LI mode. RI+SF mode can exert a positive influence on plant morphology, photosynthetic characteristics, biological yield and water and fertilizer use efficiency. The average yield was increased by 2.3%. However, the coupling effect of water and fertilizer was not fully exerted.【Conclusion】LI + SF mode is the best precise irrigation and fertilization mode in this study, and it is also suitable to be popularized as a water-saving, fertilizer saving and high-yield technology for rice in the cold area of northern China.     

Assessing water-related plant traits to explain slow-wilting in soybean PI 471938

Soybean [Glycine max (L.) Merr.] genotype PI 471938 expresses a slow-wilting phenotype in the field, and the progeny of this genotype have shown to have high yield under water deficit conditions. However, the physiological basis for the slow-wilting trait in PI 471938 remains unclear, and failure to understand the causal mechanism may limit future breeding efforts. This study investigated three primary hypotheses for trait expression that could explain slow-wilting trait in PI 471938: (1) a low osmotic potential in the leaves allowing greater water retention, (2) high elastic modulus of leaves resulting in delayed development of wilting, and (3) high hydraulic conductance allowing rapid water redistribution in the plants. Experiments included three other soybean genotypes as references for the results obtained with PI 471938. Surprisingly, the results for PI 471938 did not prove to be unique as compared to the other three tested genotypes for any of the three hypotheses. These negative results indicate that a hypothesis outside the usual candidates describing plant water transport, possibly anatomical features related to specific water transport properties, is required to explain slow-wilting in PI 471938.     

Use of field-integrated information in GIS-based maps to evaluate Moko disease (Ralstonia solanacearum) in banana growing farms in Colombia

Ralstonia solanacearum (formerly Pseudomonas solanacearum) causes large losses in more than 200 different cultivated plant species. Banana and plantain “Moko” disease is caused by R. solanacearum race 2. Moko disease may cause 100% loss if prompt control measures are not applied. Although a number of investigations have been carried out, many ecological and epidemiological aspects of R. solanacearum race 2 are still unknown, particularly in the tropics. Bacteria dispersion occurs by infested tools, soil, water, insects, domestic animals and agricultural labourers. Alternative hosts have been described which may contribute to inoculum availability in crop fields. In banana crops, cable-ways are routinely used to transport fruit and materials inside plantations. In most humid tropical areas, drainage channels are made to evacuate excess soil water. It is thought that agricultural activities associated with drainage channels and cable-ways may play a role in bacteria dispersion but individual contributions have not yet been quantified. In this work we have used field-integrated information in geographical information systems (GIS)-based maps to evaluate Moko presence in the Urabá region of Colombia, during three different time periods. A previously described risk index (RI) and losses throughout the three periods were quantified. A regression model was developed to quantify the relationship between infested area and distance from every Moko focus to the nearest cable-way and drainage channels. Farms were grouped into four different profiles according to the RI. Parameters calculated using the regression model showed that 76% of Moko foci detected during the three time periods were associated with cable-ways used for transport of fruit and consumables. This finding has important implications for disease management since bacteria spread in these ways may be prevented by simple measures taken inside plantations.     

Post-flowering leaflet removals increase pod initiation in soybean canopies

Much of the yield variation in soybean (Glycine max L. Merrill) crops is related to changes in pod and seed number. Pod number is the result of pod initiation and pod abscission while seed number is the result of potential seed per pod and seed abortion. However, the physiological regulation of these processes is not well understood. A field experiment was conducted to investigate the role of post-flowering changes in source size and canopy structure on pod initiation, pod abscission and seed abortion in soybean. Two soybean genotypes: DM48 and A7409 (maturity groups IV and VII, respectively) were used. Leaflet removal treatments (L) consisted of removing none (L0), one (L1) or two (L2) lateral leaflets of every developed trifoliate leaf present. Leaflet removals were applied twice: the first at full bloom and the second shortly after the beginning seed stage. Crop growth rate (CGR), leaf area index (LAI), light interception (LI), and relative leaf growth rate, were determined during the periods in which numerical components are established. For the period between the first and the second leaflet removal, CGR remained unchanged among L treatments in both genotypes because LAI reductions were compensated through an increase in the net assimilation rate of the remaining leaves. The first leaflet removal increased the relative leaf growth rate and the number of pods initiated (PI) and these increases were inversely related to the remaining LAI in both genotypes. Moreover, the inverse relationship between LAI and PI was sustained at LAI below and above critical (i.e., LAI for 95% LI) and was not related to CGR or LI. The number of pod abscised also increased with the level of leaflet removal during the first and main abscission period in both genotypes and the percentage of pod abscission was directly related to the seed growth rate per unit leaf area during the abscission period. Seed abortion was inversely related to LAI after the second leaflet removal. Only the highest level of leaflet removals (i.e., L2) was able to reduce seed size in both genotypes. Whereas pod abscission, seed abortion and seed size could be related to indicators of canopy assimilatory capability pod initiation was not, suggesting that other physiological mechanism/s operate in the regulation of pod initiation. In addition, our results suggest that early (i.e., at flowering) canopy closure may negatively impact pod initiation in soybean. To the best of our knowledge, this study is the first to document that the number of initiated pods is inversely related to LAI in soybean canopies.     

Variation in kernel characteristics and protein molecular weight distribution of Langdon durum-wild emmer wheat chromosome substitution lines

Triticum turgidum L. var. dicoccoides (DIC) provides a useful source of genes to improve agronomic and quality characteristics of durum wheat. Research was performed to identify DIC chromosomes that carry useful genes for quality improvement. Langdon-T. dicoccoides substitution lines consisting of 13 lines based on DIC accession PI 481521, 10 lines on PI 478742, and 2 lines on Israel A were evaluated for kernel characteristics and protein molecular weight distribution. DIC chromosomes 3A from PI 481521, and 1A and 7A from PI 478742 increased kernel hardness. Chromosome 2A from PI 481521 increased kernel weight, which resulted in increased semolina yield. Some substituted DIC chromosomes also affected grain protein concentration and protein molecular weight distribution. For example, chromosomes 2A, 5B, and 7B from PI 481521, and 6B from Israel A increased total protein concentration, which was primarily attributed to an increase of SDS soluble gliadins. Chromosome 6B from PI 478742 was unique in that it led to an increase in SDS insoluble high molecular weight polymeric proteins, which contributed to increased dough mixing strength. Results from this research indicated that chromosome 6B from PI 478742 is a potential gene source to improve dough characteristics of durum wheat by increasing insoluble high molecular weight polymeric protein concentration.     

Field confirmation of genetic variation in soybean transpiration response to vapor pressure deficit and photosynthetic compensation

Plants with limited transpiration rate (TR) under high vapor pressure deficit (VPD) offer the potential to conserve soil water and thus decrease the occurrence of soil water deficit. Genetic variability in TR response to VPD has been observed in the greenhouse for soybean (Glycine max (L.) Merr.) genotypes related to PI416937, but these differences have yet to be measured in the field. The objective of this study was to observe under field conditions leaf gas exchange properties of PI416937 in comparison to nine other genotypes to determine if it expressed limited TR at high VPD. Genotypic differences in stomatal conductance measurements (a proxy for TR) matched those obtained under controlled environment conditions. Genotypes varied from no stomatal response to VPD, to strong negative responses resulting in full stomata closure at ∼4 kPa. There was a greater proportional genetic variability in stomatal conductance in the field (75% at high VPD) than was observed in the greenhouse, but this variation was correlated with greenhouse TR. However, photosynthesis was considerably limited in genotypes that had a stomatal response to VPD. Although field differences in photosynthetic capacity among genotypes were not correlated with greenhouse measurements, there was sufficient genetic variation to allow the possibility of selection of high photosynthetic capacity to overcome about a 34% decrease in stomatal conductance. Thus, a targeted breeding program to combine the water conserving TR-VPD response with increased photosynthetic capacity has the potential to increase soybean yields in field water-deficit environments.     

Managing “Marandu” palisadegrass and calopo pastures based on light interception

Light interception (LI) in grazing management has been an efficient tool to harvest forage under similar growth stage conditions. The objective was to define the best grazing management strategies (GMSs) based on LI in marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R. Webster cv. Marandu) and calopo (Calopogonium mucunoides Desv. cv. Comum) mixed pastures. Three GMSs were evaluated in a randomized block design: rest period interrupted at 90% (90LI), 95% (95LI) and 100% (100LI) of LI. The experimental period was divided into four periods: rainy seasons and transitions (between rainy and dry seasons). Post-grazing stubble height target was 15 cm. Canopy height, forage mass, leaf area index (LAI), morphogenic variables and tiller demographic pattern were evaluated. Pre- and post-grazing canopy height increased at 100LI. Pre-grazing forage mass decreased over time in all GMSs. The relationship among canopy height, forage mass and LI was not constant throughout the experiment. Post-grazing forage mass was greatest at 90LI. There was an increase in legume mass throughout the experiment; however, the proportion of legume in pre-grazing forage mass was no more than 6.6% for all GMSs. Number of calopo branches per plant and LAI increased throughout the experiment while the number of plants decreased. The 95LI provided the best conditions for calopo development; however, the LI as a tool to determine the entry of animals in mixed pastures of marandu palisadegrass and calopo should be carefully applied, considering the seasonal variations in canopy botanical and structural composition under similar LI.     

How do severity and frequency of grazing affect sward characteristics and the choices of sheep during the grazing season?

The effect of grazing frequency and severity on sward characteristics and preferences by sheep was investigated from April to September. Two levels of grazing severity were imposed by varying the numbers of ewes grazing 200 m² plots for 24 h: four (S, severe) or two (L, lax) ewes. Grazing frequency was either 1 d week^?1 (F, frequent) or 1 d every 2 weeks (I, infrequent). By combining frequency and severity, four treatments were obtained: SF, LF, SI and LI. The six binary combinations (SF/LF, SF/SI, SF/LI, LF/SI, LF/LI and SI/LI) were studied in preference tests. Treatments LF, SI and LI were characterized by a high sward surface height, biomass and amount of reproductive green tissues relative to treatment SF. Herbage quality was not different between the grazing treatments between April and July. In September, after a 6‐week period of regrowth, herbage quality was significantly higher for the SF treatment than the other treatments. The sheep preferred the swards grazed at a low frequency between April and July, and then changed their preference in favour of the sward with higher quality herbage (treatment SF). The relative abundance of green laminae and the relative digestibility of the swards helped to explain the preferences observed. For a low grazing pressure at the spatio‐temporal scale studied, sheep should graze swards at a relatively low frequency but at a high severity of grazing rather than the reverse.     

不同品种茶树叶片功能性状及光合特性的比较

以18个茶树品种(系)为研究对象,测量了茶树叶片的叶面积、叶形指数、比叶面积、干物质含量、叶绿素a、叶绿素b及其比值、叶绿素总量、类胡萝卜素及光合特性,并分析了叶片功能性状和光合特性之间的相关性。结果表明,茶树叶片叶形指数、干物质含量、气孔导度的变异系数低于10%,其余11项指标的变异系数为15.08%~43.22%,表现出较高的多样性水平;比叶面积与干物质含量之间存在显著负相关,叶形指数和叶面积与其他叶片功能指标均无显著相关;干物质含量与光合色素之间存在显著相关,叶绿素a、叶绿素b、叶绿素a/叶绿素b、叶绿素总量和类胡萝卜素两两之间存在极显著相关性;净光合速率、气孔导度、蒸腾速率两两之间存在极显著正相关,且气孔导度与胞间CO_2浓度呈显著正相关,茶叶光合速率主要受气孔限制的影响;净光合速率与干物质含量之间存在显著正相关,净光合速率、蒸腾速率与光合色素含量之间存在显著或极显著正相关,说明光合色素含量高的品种具有更强的光合能力和干物质积累能力;气孔导度、水分利用效率与叶片功能性状之间相关性不显著。14号茶树品种比叶面积相对较低,同时具有较高的干物质含量、净光合速率和水分利用效率,属于抗旱性较强、光合速率和水分利用效率高的品种,可作为抗旱性强、高光效的茶树品种进一步选育和应用。     

Alternate Furrow Irrigation with Different Irrigation Intervals for Maize (Zea mays L.)

Abstract

This research was conducted to determine the yield and water-use efficiency of maize under fixed and variable alternate furrow irrigation (fixed AFI, variable AFI) and every furrow irrigation (EFI) at different irrigation intervals in areas with shallow and deep groundwater. In variable AFI, water was applied to the furrow, which was dry in the previous irrigation cycle. The results indicated that even at 4-day irrigation intervals the water needs of maize on a fine textured soil in both areas (with deep and shallow water table) are not met by AFI. The decrease in grain yield due to water stress was mainly due to the decrease in the number of grains per cob and to a lesser extent to the decrease in 1000-grain weight. At the Kooshkak site with shallow groundwater (between 1.31 and 1.67 m), grain yields in AFI at 4- and 7-day intervals were comparable to those obtained in EFI at 7- and 10-day intervals, respectively. This might be due to the contribution of groundwater to the water use of the plant (about 5-10%). In the Badjgah area, with deep water depth, grain yield in AFI at 7-day intervals was statistically lower than that obtained in EFI at 10-day interval. In AFI, a shorter irrigation interval (4-day) may alleviate the water stress and result in no yield reduction compared with that in EFI at 7-day intervals even though water application was reduced. Furthermore, in the area with a shallow water table, AFI at 7-day intervals may be superior to EFI at 10-day irrigation intervals. When seasonal irrigation water is less than 700 mm, it may be preferable to use AFI at 10-day intervals to increase water-use efficiency, especially in areas with shallow groundwater. In general, when water was insufficient for full irrigation, the relative grain yield (yield per unit water applied) of maize under AFI was higher than those under EFI.     

Water and air temperature impacts on rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>) phenology

Air temperature (T_a) is commonly used for modeling rice phenology. However, since the growing point of rice is under water during the vegetative and the early part of the reproductive period, water temperature (T_w) is likely to have a greater influence on crop developmental rates than T_a during this period. To test this hypothesis, we monitored T_w, T_a, and crop phenology in three commercial irrigated rice fields in California, USA. Sampling locations were set up on along a transect from the water inlet into the field. (Water warms up as it moves into the field.) T_a averaged 22.7 °C across sampling locations within each field, but average seasonal T_w increased from 22 °C near the inlet to 23.4 °C furthest away from the inlet. Relative to T_w furthest from the inlet, low T_w near the inlet delayed time to panicle initiation (PI 5 days) and heading (HD 8 days) and the appearance of one yellow hull on the main stem panicle (R7 9 days). Using T_w instead of T_a when the active growing point is under water until booting (midway between PI and HD) in a thermal time model improved accuracy (root-mean-square error, RMSE) for predicting time to PI by 2.5 days and HD by 1.6 days and R7 by 1.8 days. This model was further validated under more typical field conditions (i.e., not close to cold water inlets) in six locations in California. Under these conditions, average T_w was 2.6 °C higher than T_a between planting and booting, primarily due to higher daily maximum T_w values. Using T_w in the model until booting improved RMSE by 1.2 days in predicting time to HD. Using T_w instead of T_a during this period could improve the accuracy of rice phenology models.     

Genetic variability of transpiration response to vapor pressure deficit among soybean (Glycine max [L.] Merr.) genotypes selected from a recombinant inbred line population

Limited observations of soybean plant response of transpiration rate (TR) to vapor pressure deficit (VPD) have indicated the existence of genotypes with nearly constant TR at high VPD. The range of expression of this trait in a given population within a species has not been explored. To initiate study of this possibility, 22 genotypes from a RIL population derived from a cross of PI 416937 and Benning were characterized for their VPD response. Genotype PI 416937 has been shown to reach a maximum TR at a VPD as low as 2 kPa. Surprisingly, Benning was not found to have a continually increasing TR with VPD, but rather it had a two-segment TR response very similar to PI 416937. Unexpectedly, only one of the studied RILs had a TR response similar to the parents. Thirteen RILs had a continually increasing TR with increasing VPD. Eight RILs reached a maximum TR occurring at VPD of about 1.3 kPa, significantly lower value than that of the parents. While the inheritance of the maximum TR trait is clearly complex, these results offer encouragement that the VPD at which plants limit TR might vary so that the trait can be tailored to maximize potential yield increase in different water-deficit environments.     

茶树不同叶位叶片功能性状与光合特性研究

以5个茶树品种(系)为研究对象,分析了茶树新梢不同叶位叶片的叶面积(LA)、叶形指数(LI)、比叶面积(SLA)、干物质含量(LDMC)、叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素总量(Chl)、类胡萝卜素(Car)及光合特性,并研究了叶片功能性状和光合特性之间的相关性。结果表明,不同叶位叶片的LA、LMDC、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)由第1叶至第6叶基本呈现先增加后降低趋势,新梢中部3~4叶达到峰值,第1叶和第6叶显著降低(P0.05);不同叶位叶片LI和SLA基本呈现随着叶位增加而增加的趋势,第6叶的SLA均显著高于其他叶位(P0.05);第1~4叶的Chla、Chlb和Chl含量较高,第6叶Chla、Chlb和Chl含量显著低于其他叶位(P0.05),Car变化趋势不明显。LA与LI、LDMC、Chla、Chlb、Chl和Car之间存在显著或极显著正相关,与胞间CO2浓度(Ci)之间呈显著负相关,与其他指标相关性不显著;LI与其他指标不相关(LA除外);SLA与LDMC、Chla、Chlb、Chl、Car和Pn之间存在显著或极显著负相关,与Ci之间呈极显著正相关,与其他指标相关性不显著;LDMC与Chla、Chl和Pn之间存在显著或极显著正相关;Chla、Chlb、Chl和Car两两之间均存在极显著正相关,且均与Pn存在显著或极显著正相关;Gs和Tr与叶片功能性状不相关。分析以上结果可以得出,茶树新梢第3~4叶具有相对较大的LA和较强的光合能力,LDMC积累较大,可以作为表征茶树光合能力的供试叶片;SLA、LDMC和光合色素含量与Pn存在密切相关性,可作为评价茶树光合能力的指标。     

大豆异黄酮合成关键酶基因对蚜虫取食的防御响应分析

以蚜虫差异抗性的大豆品种PI567598B(高抗)、绥农30(抗)、东农51(中抗)和Williams 82(感)为试验材料,分别于接种大豆蚜虫0,7,14和21 d时采集大豆叶片,利用q PCR对异黄酮合成关键酶基因苯丙氨酸解氨酶(PAL)、黄烷酮-3-3羟化酶(F3H)、大豆异黄酮合成基因1(ISF1)和大豆异黄酮合成基因2(ISF2)的表达量进行分析。结果表明:蚜虫取食前高抗品种PI567598B中PAL、F3H、ISF1和ISF2基因的相对表达量均高于感虫品种Williams 82;蚜虫取食后,抗蚜品种PI567598B和绥农30中PAL基因在蚜虫取食14 d时显著上调,在21 d时达到最大,F3H基因7 d时表达量最高,然后降低;IFS2表达量于蚜虫取食7 d后显著上调,在21 d时达到最大;中抗品种东农51中PAL、IFS2和F3H基因表达量在7 d时增加,但不显著;而感蚜品种Williams 82蚜虫取食后PAL和IFS2表达量增加但不显著,且相对表达量显著低于抗蚜品种,F3H基因表达量不增反降;抗感大豆品种蚜虫取食后IFS1基因表达均诱导不显著。研究表明,感蚜大豆品种蚜虫取食前后异黄酮合成关键酶基因表达量都比较低,而抗虫品种异黄酮合成关键酶基因表达量高,且防御响应持续时间长,符合其抗性差异。     

铁观音茶梗中挥发性物质分析

本研究以铁观音茶梗为供试材料,采用顶空进样法-气质联用(HS-GC/MS)技术对其挥发性物质进行提取和检测,利用质谱结合保留指数对其进行定性,并对挥发物种类、相对含量及部分挥发物所具备的生物活性进行比较和探讨。结果表明:从安溪铁观音茶梗中共检测出130种化合物,其中共有的成分108种;采用质谱法(mass spectrometry,MS)完全鉴定出45种、初步鉴定出58种,采用各化合物的保留指数(retention index,RI)鉴定出54种;MS与RI相结合共完全鉴定出68种挥发物。这表明谱库检索与保留指数相结合,有利于提高可定性挥发物的数量以及定性的准确度。在梗中,碳氢类化合物、醛、醇、酯的种类和含量都最为丰富,相对含量高于1%的挥发物有24种,部分挥发物具有麻醉、抑菌、抗癌等生物活性作用,其含量占茶梗挥发物总含量的20.51%。该结果为研究茶梗在形成乌龙茶香气品质中所起的作用及茶梗的综合利用提供理论基础。     

Photoinduced reaction of lyocell with water-soluble photoinitiator and multifunctional acrylate

The photo-induced reactivity of lyocell fabrics containing two water-soluble photoinitiators and multifunctional acrylate was characterized by the UV absorption and photoluminescence properties. The relative quantum yields of the fluorescence and phosphorescence were analyzed at three exciting wavelengths and the proportional constants were compared. The fabrics containing [2-(acryloyloxy)ethyl](4-benzoylbenzyl)dimethylammonium bromide (PIA) and 1,3,5-triacryloylhexahydro-s-triazine (TAF) exhibited smaller relative quantum yields than the fabrics containing [3-(3,4-dimethyl-9-oxo-9h-thioxanthene-2-yloxy)-2-hydroxypropyl]trimethylammonium chloride (PIB) and TAF. The modified cellulose fabrics with tertiary amine also had smaller relative quantum yields than regular fabrics. We found that the cellulose/PIA/TAF system was a more photoactive process than the cellulose/PIB/TAF system and that the AM/PI/TAF system was more active than the regular/PI/TAF system. Furthermore, a TAF molecule was proved to have photo-reactivity with cellulose by a comparison between the proportional constants in the fluorescence quantum yields of PI/TAF solutions and cellulose/PI/TAF fabrics. These fabrics were irradiated by a high-power UV system with an electrodeless lamp. FTIR-ATR spectra showed that TAF molecules were successfully introduced to the surfaces of the irradiated fabrics. Thermogravimetric analysis showed that the thermal stability increased and the degree of thermal depolymerization decreased with the addition of PI and TAF; therefore, it was inferred that TAF molecules were cross-linked between adjacent cellulose chains to some degree. These results agreed well with the ESCA data; the N_1s/C_1s ratios increased and O_1s/C_1s ratios decreased with the TAF addition. The water retention value (WRV) decreased because of the drop in swellability of the cross-linked fabric and the moisture regain value (MRV) decreased because the total water absorption sites diminished. In particular, the irradiated cellulose/PIA/TAF fabrics exhibited more distinct effects than the irradiated cellulose/PIB/TAF fabrics and the AM/PI/TAF fabrics were more photoactive in this UV-irradiation system than regular/PI/TAF fabrics.     

Purified Brominated Indole Derivatives from Dicathais orbita Induce Apoptosis and Cell Cycle Arrest in Colorectal Cancer Cell Lines

Dicathais orbita is a large Australian marine gastropod known to produce bioactive compounds with anticancer properties. In this research, we used bioassay guided fractionation from the egg mass extract of D. orbita using flash column chromatography and identified fractions containing tyrindoleninone and 6-bromoisatin as the most active against colon cancer cells HT29 and Caco-2. Liquid chromatography coupled with mass spectrometry (LCMS) and ¹H NMR were used to characterize the purity and chemical composition of the isolated compounds. An MTT assay was used to determine effects on cell viability. Necrosis and apoptosis induction using caspase/LDH assay and flow cytometry (PI/Annexin-V) and cell cycle analysis were also investigated. Our results show that semi-purified 6-bromoisatin had the highest anti-cancer activity by inhibiting cell viability (IC₅₀ = ~100 µM) and increasing caspase 3/7 activity in both of the cell lines at low concentration. The fraction containing 6-bromoisatin induced 77.6% apoptosis and arrested 25.7% of the cells in G2/M phase of cell cycle in HT29 cells. Tyrindoleninone was less potent but significantly decreased the viability of HT29 cells at IC₅₀ = 390 µM and induced apoptosis at 195 µM by increasing caspase 3/7 activity in these cells. This research will facilitate the development of these molluscan natural products as novel complementary medicines for colorectal cancer.     

In Vitro Antitumor Activity of Stellettin B,a Triterpene from Marine Sponge Jaspis stellifera,on Human Glioblastoma Cancer SF295 Cells

Stellettin B was isolated from marine sponge Jaspis stellifera. In vitro antitumor activities were investigated on 39 human cancer cell lines. Stellettin B exhibited highly potent inhibition against the growth of a human glioblastoma cell line SF295, with a GI50 of 0.01 μM. In contrast, stellettin B showed very weak inhibitory activity on normal cell lines including HMEC, RPTEC, NHBE and PrEC, with GI50s higher than 10 μM, suggesting its relatively selective cytotoxicity against human cancer cells compared to normal human cell lines. We then focused on the antitumor activity of this compound on SF295 cells. Flow cytometric analysis indicated that stellettin B induced apoptosis in SF295 cells in a concentration-dependent manner. Further study indicated that stellettin B increased the production of ROS, the activity of caspase 3/7, as well as the cleavage of PARP, each of which is known to be involved in apoptosis. To investigate the molecular mechanism for cell proliferation inhibition and apoptosis induction, effect on the phosphorylation of several signal proteins of PI3K/Akt and RAS/MAPK pathways was examined. Stellettin B inhibited the phosphorylation of Akt potently, with no activity on p-ERK and p-p38, suggesting that inhibition of PI3K/Akt pathway might be involved in the antiproliferative and apoptosis-inducing effect. However, homogenous time-resolved fluorescence (HTRF) assay indicated that stellettin B did not inhibit PI3K activity, suggesting that the direct target might be signal protein upstream of Akt pathway other than PI3K.     

Evaluation of tuber-bearingSolanum species for symptomology,as diagnostic hosts,and sources of immunityto potato virus Y necrotic strain (PVYN)

A total of 258 Plant Introductions (PI) belonging to 69Solarium species were evaluated in the greenhouse for their reaction to the tobacco veinal necrosis strain of potato virus Y (PVY N). One hundred and thirty-one (50.7%) of the PI accessions produced mosaic symptoms ranging from mild to severe. Local lesion and veinal necrosis symptoms were observed in 19 PI accessions (7.3%) and a variety of other symptoms were observed in another 11 PI accessions (4.2%). Only 97 PI accessions (37.5%) were symptomless carriers of PVY^N. PI accession 473505 ofS. sparsipilum and PI accession 498021 ofS. brachycarpum developed local lesions and veinal necrosis with PVY^N, but necrotic spots and mosaic with PVY^o. Common mechanically-transmitted potato viruses A, S, M, and X did not interfere with PVY symptom development inS. sparsipilum andS. brachycarpum. Thus, PI 473505 and PI 498021 can be used as indicator plants for specific identification of PVY^N. PI accession 472819 ofS. chacoense developed local lesions with systemic spread in PVY^o, but without systemic spread in PVY^N. Thus, this can be used as a differential host plant for PVY strains. Two PI accessions ofS. stoloniferum, PI 160372 and 161171 were immune to PVY^N.