Photosynthesis and Dry Matter Accumulation in Different Chlorophyll-Deficient Rice Lines

Three different chlorophyll-deficient rice isogenic lines chl,fgl and pgl,and their recurrent parent zhefu802 （zf802） were used to study effects of leaf color on photosynthesis,dry matter accumulation,yield,and quality in early season indica rice.Analysis showed that the chlorophyll （Chl.） a/b ratio of isogenic lines chl-8,pgl and fgl was 5.35,10.00 and 15.46,respectively,among them,line fgl had higher leaf area index （LAI）,higher net photosynthetic rate and higher grain-filling rate than its recurrent parent zf802 at the later period of grain filling stage;while LAI,net photosynthetic rate and dry matter accumulated in lines chl-8 and pgl were lower than in zf802.Differences were found in the grain yield and quality among chlorophyll deficient isogenic lines,lines fgl,chl-8 and zf802 had similar grain yield,which was significantly higher than that of pgl;the highest milling quality was observed in isogenic line fgl,with relatively high protein content.This study showed that isogenic line fgl would become a unique material for the development of high yield rice with high grain quality because of its slow aging process and relative steady grain-filling rate.

Characterization of a Novel Chlorophyll-Deficient Mutant Mt6172 in Wheat

Identification of new chlorophyll-deficient mutants will provide materials for studying signaling components and pathways between plastid and nucleus. A novel chlorophyll-deficient mutant, named Mt6172, was obtained by spaceflight environment induction. Genetic analysis showed that its inheritance was controlled by nuclear and cytoplamic genes. Leaf color of its self-fertilized progenies was albino, narrow-white striped, or green. Only a few cells with abnormal chloroplasts were observed in albino plants and white section of narrow-white striped plants. These chloroplasts had obvious flaws in inner structure, and granum lamellae was extremely disordered. The narrow-white striped plants were characterized with green- and-narrow-white striped leaves, and the width of stripes between different plants was even, their plant height, number of productive tillers, and 1 000-grain weight were lower than those of the wild type. The narrow-white striped plants and the wild type had significant difference in the value of potential activity of photosystem II at all tested stages. At elongation stage, which was impacted the most seriously, effective quantum yield significantly decreased, whereas the energy for photoprotection and photodamage significantly increased. changes of electron transport rate, photochemical dissipation, Under different photosynthetic active radiation conditions, and effective quantum yield were different, electron transport rate was more impacted than other parameters. Therefore, the leaf morphology and inheritance of mutant Mt6172 was different from the other reported mutants in wheat, and it was a novel mutant of chloroDhvll deficiency.

Characterization of CircRNA-Associated CeRNA Networks in Folate Deficiency-Induced Neural Tube Defects

Objective Circular RNAs(circRNAs)participate in several important pathological processes and have been used in the diagnosis and treatment of various diseases.This study aimed to investigate the role of circRNAs in neural tube defects(NTDs).Method We characterized circRNA-associated competitive endogenous RNA(ceRNA)networks in brain tissue of low folate-induced NTDs mouse at embryonic day 13.5 by high-throughput sequencing.The expression levels of Circzfp644,miR-20-5p and Gas7 were detected by RT-PCR.Gas7 and Circzfp644functions were determined by miRNA-mimics and inhibitors in mouse teratocarcinoma cells(F9 cells),and luciferase gene reporter assay was assessed in the F9 cells.In addition,the expression levels of Circzfp644,miR-20-5p and Gas7 were determined by Nanostring in human NTDs tissues.Results We detected 57 circRNA transcripts,16 miRNAs,and 148 mRNAs that were significantly dysregulated in NTDs brain tissues compared with their expression levels in control(normal)tissues.Circzfp644 shared miRNA response elements with the growth arrest specific 7(Gas7)gene and competitively bound with miR-20-5p to increase the expression of Gas7.Downregulation of Circzfp644and Gas7 and upregulation of miR-20-5p were found in human NTD tissue.Conclusion This study provides new perspectives on the role of circRNAs in nervous system development and the pathogenesis of NTDs.

Abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type

Objective:To explore the abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type.Methods:The 30 healthy individuals included in the method were from the Physical Examination Center of Anhui Provincial Hospital of Traditional Chinese Medicine,and the 60 rheumatoid arthritis patients included were from the First Affiliated Hospital of Anhui University of Traditional Chinese Medicine.The disease activity score of patients with rheumatoid arthritis was evaluated using VAS score and DAS28 score,joint symptoms and spleen deficiency syndrome score were evaluated using graded quantification method,immune inflammation indicators were detected using relevant instruments,inflammatory cytokines were detected using ELISA method,macrophage markers were detected using FCM method,and pathway gene expression was detected using RT-qPCR;Evaluate the predictive effect of circ-CBLB and miR-486-5p on disease activity in rheumatoid arthritis using ROC curves.Results:(1)miR-486-5p,CD14^(+)CD86^(+),ESR,CRP,RF,Anti CCP Ab,IL-6,TNF in patients with rheumatoid arthritis-αThe levels of circ-CBLB,CD14^(+)CD163^(+),IL-4,and IL-10 were significantly higher than those of healthy individuals;(2)The expression level of circ-CBLB in patients with rheumatoid arthritis is positively correlated with CD14^(+)CD163^(+),and negatively correlated with miR-486-5p and CD14^(+)CD86^(+);The expression level of miR-486-5p is negatively correlated with CD14^(+)CD163^(+)and positively correlated with CD14^(+)CD86^(+);There is a negative correlation between CD14^(+)CD86^(+)and CD14^(+)CD163^(+);ESR is negatively correlated with circ-CBLB,and positively correlated with miR-486-5p,CD14^(+)CD86^(+),CRP;CRP is negatively correlated with circ-CBLB,CD14^(+)CD163^(+),and positively correlated with CD14^(+)CD86^(+),ESR;(3)The expression level of circ-CBLB in patients with rheumatoid arthritis is negatively correlated with joint tenderness,morning stiffness,lack of qi and lazy speech,and postprandial abdominal distension score;The expression level of miR-486-5p is positively correlated with the scores of joint tenderness and decreased appetite.(4)The ROC curve shows that in terms of circ-CBLB,ESR,CRP,VAS,and DAS28 AUC are 0.662(P=0.032),0.658(P=0.035),0.516(P=0.830),and 0.791(P=0.000),respectively.In terms of miR-486-5p,ESR,CRP,VAS,and DAS28 AUC were 0.566(P=0.385),0.511(P=0.883),0.592(P=0.223),and 0.727(P=0.003),respectively.Conclusion:The abnormal expression of circ CBLB and miR-486-5p in peripheral blood mononuclear cell of patients with rheumatoid arthritis of spleen deficiency and dampness excess type is related to inflammatory polarization markers,immune inflammation,disease activity,joint symptoms and spleen deficiency syndrome of rheumatoid arthritis,and the low expression of circ CBLB and high expression of miR-486-5p have certain predictive value for disease activity of rheumatoid arthritis.

NO_3^-/NH_4^+ ratios affect plant growth, chlorophyll content,respiration rate, and morphological structure in Malus hupehensis seedlings

Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4＋concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4＋ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll （a, b, and a ＋ b） content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4＋ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4＋ concentration. However, the opposite trend occurred at the NO3-/NH4＋ ratio of 0/100. Chloro- phyll （a, b, and a ＋ b） content was lowest at the NO3-/NH4＋ ratio of 100/0 than at the other ratios. At the NO3-/ NH4＋ ratio of 0/100, oxygen （02） consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4＋ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.

Effects of Different Potassium Stress on Leaf Photosynthesis and Chlorophyll Fluorescence in Maize (Zea Mays L.) at Seedling Stage

Leaf early senescence caused by nutrition deficiency is one of the major limitation reasons in the world crop production. Potassium (K) is one of important nutrient elements in crop growth, which modifies dozens of enzyme activations and controls stomatal movement of photosynthesis. The yield and quality of maize (Zea Mays L.) have been limited due to K deficiency in plough layer soil. However, the mechanism of K deficiency tolerance is not fully understood in maize. In this study, two inbred lines, 099 (tolerance to potassium deficiency) and 835 (sensitive to potassium deficiency) were carried out to investigate the variations of chlorophyll content, photosynthetic and chlorophyll fluorescence parameters related with senescence under different K+ concentrations in maize at seedling stage. The results showed that the Chlorophyll a, b and (a + b) of 835 were significantly decreased under different K deficiency treatments, whereas those of 099 were remained normal. In addition, 099 showed a lower stomatal restriction and higher electronic transition capacity under different K deficiency treatments. The variations of F0, Fv/Fm, ΦPSⅡ, qP and NPQ in 835 were largely higher than those in 099. These results indicated that the inbred line 099 tolerance to K deficiency could keep chlorophyll content to maintain photosynthesis and to alleviate the injury of PSII under K deficiency condition. This study should contribute to explaining the physiological mechanism tolerance nutrition deficiency and improving breeding program in maize.

Fertilizer-Induced Advances in Corn Growth Stage and Quantitative Definitions of Nitrogen Deficiencies

Evidence that nitrogen (N) fertilization tends to accelerate maturation as well as increase rates of growth has received little attention when diagnosing N deficiencies in corn (Zea mays L.).Such a tendency could be a potential source of errors when the diagnosis is solely based on comparing plants with different rates of growth.Whether N fertilization could accelerate rates of growth and maturation was tested in a field study with 12 paired plots representing relatively large variability in soil properties and landscape positions.The plots were located under conditions where preplant N fertilization reduced or avoided temporary N shortages for some plants but did not reduce for other plants early in the season.We measured corn heights to the youngest leaf collar,stages of growth and chlorophyll meter readings (CMRs). The added N advanced growth stages as well as increased corn heights and CMRs at any given time.Fertilization effects on corn heights,growth stages and ear weights were statistically significant (P<0.05) despite substantial variability associated with landscape.Reductions in growth due to a temporary shortage of N within a growth stage might be partially offset by longer periods of growth within that stage to physiological maturity.Temporary shortages of N,therefore,may produce symptoms of N deficiency in situations where subsequent additions of N should not be expected to increase yields.Recognition of these two somewhat different effects (i.e.,increase growth rates and advance growth stages) on corn growth could help to define N deficiency more precisely and to improve the accuracy of diagnosing N status in production agriculture.

Δ4-3-oxosteroid-5β-reductase deficiency: Responses to oral bile acid therapy and long-term outcomes

BACKGROUND Disorders of primary bile acid synthesis may be life-threatening if undiagnosed,or not treated with primary bile acid replacement therapy. To date, there are few reports on the management and follow-up of patients with Δ4-3-oxosteroid 5β-reductase(AKR1 D1) deficiency. We hypothesized that a retrospective analysis of the responses to oral bile acid replacement therapy with chenodeoxycholic acid(CDCA) in patients with this bile acid synthesis disorder will increase our understanding of the disease progression and permit evaluation of this treatment regimen as an alternative to the Food and Drug Administration(FDA) approved drug cholic acid, which is currently unavailable in China.AIM To evaluate the therapeutic responses of patients with AKR1 D1 deficiency to oral bile acid therapy, specifically CDCA.METHODS Twelve patients with AKR1 D1 deficiency, confirmed by fast atom bombardment ionization-mass spectrometry analysis of urine and by gene sequencing for mutations in AKR1 D1, were treated with differing doses of CDCA or ursodeoxycholic acid(UDCA). The clinical and biochemical responses to therapy were monitored over a period ranging 0.5-6.4 years. Dose adjustment, to optimize the therapeutic dose, was based on changes in serum biochemistry parameters,notably liver function tests, and suppression of the urinary levels of atypical hepatotoxic 3-oxo-Δ4-bile acids measured by mass spectrometry.RESULTS Physical examination, serum biochemistry parameters, and sonographic findings improved in all 12 patients during bile acid therapy, except one who underwent liver transplantation. Urine bile acid analysis confirmed a significant reduction in atypical hepatotoxic 3-oxo-Δ4 bile acids concomitant with clinical and biochemical improvements in those patients treated with CDCA. UDCA was ineffective in down-regulating endogenous bile acid synthesis as evidenced from the inability to suppress the urinary excretion of atypical 3-oxo-Δ4-bile acids. The dose of CDCA required for optimal clinical and biochemical responses varied from 5.5-10 mg/kg per day among patients based on maximum suppression of the atypical bile acids and improvement in serum biochemistry parameters, and careful titration of the dose was necessary to avoid side effects from CDCA.CONCLUSION The primary bile acid CDCA is effective in treating AKR1 D1 deficiency but the therapeutic dose requires individualized optimization. UDCA is not recommended for long-term management.

17α-hydroxylase/17,20 carbon chain lyase deficiency caused by p.Tyr329fs homozygous mutation:Three case reports

p.Tyr329fs is a cytochrome P450c17 mutation among Chinese individuals.However,data on 17-α-hydroxylase deficiency caused by cytochrome P450c17 p.Tyr329fs homozygous mutation are lacking.This paper is a case report of three patients homozygous for p.Tyr329fs who were diagnosed with 17-α-hydroxylase deficiency between 2005 and 2019.CASE SUMMARY Case 1 presented with hypertension,hypokalemia,sexual infantilism and delayed bone age.The patient had a 46,XY karyotype,was homozygous for p.Tyr329fs and was recently treated with dexamethasone 0.375 mg qn.Case 2 presented with hypokalemia,sexual infantilism,osteoporosis and delayed bone age.The patient had a 46,XY karyotype,was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn at the last follow-up.Serum potassium and blood pressure could be maintained within normal range for cases 1 and 2.Case 3 presented with amenorrhea,sexual infantilism,osteopenia and delayed bone age.The patient had a 46,XX karyotype,was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn and progynova 1 mg qd.Outpatient follow-up revealed an adrenocorticotropic hormone(8 AM)of<5.00 pg/mL.CONCLUSION The homozygous p.Tyr329fs mutation usually manifests as a combined deficiency,and definitive diagnosis depends primarily on genetic testing.

芥菜型油菜黄化突变体L638-y叶片氨基酸合成代谢的变化

【目的】探明芥菜型油菜黄化突变体L638-y叶片氨基酸合成代谢网络变化。【方法】以芥菜型油菜黄化突变体L638-y及其野生型L638-g为材料,用氨基酸自动分析仪及实时定量PCR,检测并分析了幼苗叶片游离氨基酸含量及氨基酸合成代谢中8个重要基因的相对表达量。【结果】1)芥菜型油菜黄化突变体L638-y幼苗叶片游离氨基酸总量低于野生型L638-g,被检测出的17种游离氨基酸中,有10种氨基酸含量低于野生型L638-g,而其他7种则高于野生型L638-g;各游离氨基酸的含量在突变体L638-y与野生型L638-y叶片之间变化幅度不尽相同,其中差异显著的是甘氨酸、甲硫氨酸、异亮氨酸、亮氨酸、酪氨酸、精氨酸,谷氨酸的变化最小。2)氨基酸合成代谢中8个重要基因表达量变化的分析结果表明,仅谷氨酸族氨基酸生物合成的谷氨酸合酶基因(GSR)的表达在L638-y中呈上调表达趋势,其余的7个基因,即谷氨酰胺合成酶基因(GLN)、天冬氨酸氨基转移酶基因(GOT)、天冬酰胺合成酶基因(ASN)、Δ′-二氢吡咯-5-羧酸还原酶基因(P5CR)、丙氨酸氨基转移酶基因(AAT)、3-磷酸甘油酸脱氢酶基因(PGDH)、ATP磷酸核糖转移酶基因(ATP-PRT)均下调表达。3)在突变体L638-y叶片氨基酸合成代谢途径中,8个重要基因表达量的变化与相关游离氨基酸含量的变化并不一致,表明氨基酸合成代谢受到了抑制。【结论】芥菜型油菜黄化突变体L638-y幼苗叶片中氨基酸合成代谢和氮代谢受到了抑制。

大豆黄绿叶突变体NJ9903-5性状表现与基因定位研究

叶色突变体既可用于作物叶绿素合成、降解和光合作用等研究,也可作为标记基因为作物育种利用。本文对一个新发现的大豆黄绿叶自发突变体NJ9903-5进行遗传鉴定。结果表明:从对生真叶开始,该突变体幼嫩叶呈黄色,随着生长叶片逐渐转变为绿色。黄化叶片叶绿体数目下降,基质片层减少且排列疏松,叶绿素a、b、类胡萝卜素含量都极显著下降;其对株高、主茎节数、单株粒数、单株荚数有负效应,但对百粒重、蛋白质含量、油脂含量影响小,杂交后代中上述性状变异大。3个杂交群体遗传分析表明该性状受一对隐性核基因控制,利用F2隐性个体将目标基因ygl定位在SSR标记BARCSOYSSR_02_1445和BARCSOYSSR_02_1477之间约366 kb区段,包含36个候选基因。测序分析发现在突变体中,叶绿体膜转运蛋白相关基因Glyma.02G233700第1个外显子第38个碱基G缺失,移码突变导致蛋白翻译提前终止,结合前人研究结果,推测其为黄绿叶的目的基因ygl。

Physiological and molecular responses of invasive cyanobacterium Raphidiopsis raciborskii to ambient phosphorus deficiency

Raphidiopsis raciborskii can cause harmful cyanobacterial blooms when concentrations of environme ntal pho sphorus(P)are very low,thus the physiological and molecular mechanisms involved in the acclimation to P need to be characterized better.The growth,chlorophyll fluorescence,alkaline phosphatase,and expression of genes directly involved in P assimilation were compared in the R.raciborskii FACHB1496 strain grown with and without inorganic P.The specific growth rate(μ),Chl a,and six fluorescence parameters(minimal fluorescence(F),maximal fluorescence(F),maximal variable fluorescence(F),electron transport flux(further than QA)per RC(ET/RC),quantum yield of the electron transport in PSⅡ(?),and the probability that an electron from a trapped exciton is moved into the electron transport chain beyond Q~-(Ψ))markedly decreased in R.raciborskii in response to experimental P-deficiency.In contrast,the relative variable fluorescence at the J-step(V),trapped energy flux(leading to QA reduction)per RC(TR/RC),and alkaline phosphatase activity significantly increased.In addition,gene expressions involved in the alkaline phosphatase(phoAl and phoA2),high-affinity inorganic P transporter(pstSl),phosphonate transporter and metabolism(phnD and phnM),and nucleotidase(nucH)were significantly upregulated under P deficiency.However,physiological and molecular responses were resumed rapidly after P re-supplementation following P-deficient conditions.Our results highlight that R.raciborskii can perform coordinated and complex cellular and physiological responses to cope with P deficiency,reflecting R.raciborskii’s multi-faceted machinery to respond to environmental P fluctuations.

Differences in Physiological Age Affect Diagnosis of Nitrogen Deficiencies in Cornfields

Many studies have shown that chlorophyll meter readings(CMRs) can be used to diagnose deficiencies of nitrogen(N) during the growth of corn(Zea mays L.) in small-plot trials,but there is need to address additional problems encountered when diagnoses are made in fields of the size managed in production agriculture. A noteworthy difference between smallplot trials and production agriculture is the extent to which the effects of N are confounded with the effects of other factors such as tillage,landscape,soil organic matter and moisture content. We illustrate how some of these factors can cause differences in the physiological age of plants and introduce errors in the diagnoses of N deficiencies. We suggest methods(measuring the height to the youngest leaf collar and assigning leaf numbers by using the first leaf with pubescence and the ear leaf as references to identify growth stages) for minimizing these errors. The simplified method of growth stage identification can be used to select appropriate plants and leaves for making diagnoses in fields and to distinguish the effects of N from the effects of other factors that infiuence plant growth.

Vitamin A supplement: a key strategy to prevent vitamin A deficiency among young children in Afghanistan

Background:Vitamin A deficiency is the main problem of public health worldwide demonstrated that 190 million population of preschool children and 122 countries(in Africa and South-East Asia)have vitamin A deficiency,according to recent estimated research.In Afghanistan,vitamin A supplementation is a key strategy to prevent vitamin A deficiency among young children.Children receive vitamin A supplements as part of National Immunization Days(NID)campaigns.Methods:In this case study,the data was collected from June 15/2015 to February 23/2016,and the final report of the Afghanistan Demographic Health Survey(AfDHS)2015 was released on February 15/2017.All 27,209 children aged 6-59 months who are living with their mothers were included in this study.Who consumed foods rich in vitamin A was not included in this study.Results:The percentages who were given vitamin A supplements in the last 6 months among all children 6-59 months aged.A total of 1,572 children aged among 6-8 months were given vitamin A supplements 670(42.6%)children and comparison with the total community of the study(27,209)children(2.46%).A total of 1,148 children aged among 9-11 months were given vitamin A supplements to 465(40.5%)children and comparison with the total community of the study(27,209)children(1.70%).Conclusion:After following up on more studies,we found that vitamin A deficiency is a public problem,thus it is better to use wheat flour fortification,vitamin A capsule(VAC)supplementation,nutrition education,source of vitamin A,and training of primary healthcare workers on the clinical to prevent and treat the vitamin A deficiency among children.Therefore,we aimed to determine the given vitamin A supplementation among children aged 6-59 months in 33 provinces in Afghanistan,in 2015.

不同磷效率紫花苜蓿叶绿素荧光参数对低磷胁迫的响应

【目的】探讨不同磷效率紫花苜蓿(Medicago sativa L.)叶片光合性能对低磷胁迫的响应,从光能转化和利用的差异来揭示品种适应磷胁迫的机理。【方法】试验采用砂培法,供试材料为2个磷高效紫花苜蓿品种甘农6号(G6)、极光(JG)和2个磷低效品种Bara 310SC(B310)、甘农4号(G4)。以1/4霍格兰营养液为基础,设置磷浓度为0.5 mmol/L(正常对照)和0.05 mmol/L(低磷)两个处理水平,紫花苜蓿幼苗处理30天后,测定苜蓿幼苗叶片叶绿素荧光参数,将样品烘干后,测定生物量和磷含量。【结果】与对照相比,低磷胁迫下4个苜蓿品种的生物量和磷利用效率均降低,相对可变荧光诱导曲线J点和I点的荧光强度上升,初级醌受体(Q_(A))被还原的最大速率(M_(o))显著增加,受体库容量(S_(m))等参数下降,PSⅡ受体侧受损;活性反应中心数目(RC/CS_(o))降低,光能的吸收(ABS/RC、ABS/CS_(o))、捕获(TR_(o)/RC、TR_(o)/CS_(o))、传递(ET_(o)/RC)和耗散(DI_(o)/RC、DI_(o)/CS_(o))显著增加,性能指数(PI_(abs)和PI_(total))降低,光合电子传递受阻,PSⅠ和PSⅡ的整体性能降低。从品种间差异来看,磷高效利用型品种G6和JG这些参数的变化幅度均小于磷低效利用型品种B310和G4,且在相同磷处理下具有较高的生物量和磷利用效率。【结论】低磷胁迫主要抑制苜蓿叶片受体侧及反应中心电子传递链性能,使PSⅠ和PSⅡ性能下降,光合电子传递受阻,最终导致生物量和磷利用效率降低。与磷低效利用型品种相比,磷高效利用型品种具有较高的光合电子传递活性,能较好的维持光合系统的稳定性;与其他荧光参数相比,PI_(abs)对低磷胁迫最为敏感,且与磷利用效率显著正相关,能有效的反映PSⅡ光能转化效率、活性反应中心和受体侧的状况,是评估低磷胁迫下苜蓿光合活性的有效指标。

铁对缺磷和铝毒耦合胁迫下杉木耐铝性的影响

为探究酸性土壤中铁与缺磷和铝毒耦合胁迫的互作关系及其对杉木耐铝性的影响,以杉木优良基因型YX11实生苗为材料,采用控制条件下沙培试验方法,设置对照(CK)、铝胁迫(Al)、缺磷和铝毒耦合胁迫(-P+Al)、缺磷和铝毒耦合胁迫下缺铁处理(-P+Al-Fe),研究缺磷和铝毒耦合胁迫下,外源供铁对杉木幼苗生长、光合生理、植株铝和铁含量、叶片抗性生理的影响。结果表明:(1)Al胁迫处理能显著抑制杉木幼苗生长,-P+Al处理进一步加剧Al诱导的生长受抑,而-P+Al-Fe处理则能显著缓解-P+Al处理引起的生长受抑程度。(2)杉木叶片光合色素含量,叶绿素荧光参数最大荧光(F_(m))、可变荧光(F_(v))、PSⅡ潜在光化学活性(F_(v)/F_(o))、PSⅡ最大光化学效率(F_(v)/F_(m))、光化学淬灭系数(qP)和实际最大量子产额(QY)以及叶片净光合速率在不同胁迫处理下均较CK出现不同程度下降,但-P+Al处理的降幅显著大于-P+Al-Fe处理。(3)杉木叶片SOD、POD、CAT和APX等抗氧化酶活性在不同胁迫处理下均比CK显著增加,但-P+Al处理各抗氧化酶活性增幅显著低于-P+Al-Fe处理,从而导致-P+Al处理叶片形成更多过氧化氢,积累大量丙二醛。(4)杉木根和叶片铝含量在不同胁迫处理下均比CK显著增加,但根和叶片中铝含量在-P+Al-Fe和-P+Al处理间无显著差异,而-P+Al处理根和叶片中铁含量显著高于-P+Al-Fe处理。研究发现,在缺磷和铝毒耦合胁迫下,与缺铁相比,正常供铁能显著促进铁在杉木植株体内的积累,抑制其抗氧化酶活性的增强,促进过氧化氢大量积累,造成光合色素降解,同时对质膜和光合反应中心造成不可逆损伤,显著降低光合效率,加剧铝毒诱导的杉木生长受抑程度。

Water Stress Early Detection of Eggplant Plants by Hyperspectral Fluorescence Spectroscopy

Water stress early detection is essential for precision farming to improve crop productivity and product quality. The methods usually used are destructive, long and expensive. In this work, we used hyperspectral chlorophyll fluorescence technology as a rapid, non-destructive approach to detect the water deficiency of eggplant plants using their spectral footprint. So, an experiment was made on 54 eggplant plants subjected to three water treatments: normal irrigation (T100), intermediate irrigation (T50) and no irrigation (T0). The fluorescence spectra were acquired in vivo and in situ using a USB4000 spectrometer from Ocean optics. For the classification of the plants subjected to three water treatments, we used three pretreatments of the raw hyperspectral data in order to suppress the non-informative variability present in these spectra and to obtain robust models. These are the Savitzky-Golay smoothing (SG), the standard normal variable (SNV) and the first derivative of Savitzky-Golay (SG-D1). The preprocessed data were then subjected to two partial least squares discriminant analyses (PLS-DA): Hard PLS-DA and Soft PLS-DA. These statistical approaches are suitable for large samples as it reduces the dimensionality of the data but improves the accuracy of the prediction. The SG-D1 combined with the Soft PLS-DA gave the best discrimination of plants with scores of sensitivity, specificity and total efficiency respectively of 97.33%, 94% and 95% for calibration, 6 days after hydric stress induction. For the plants used for the prediction, the scores are 86%, 91% and 90% respectively. This study shows that hyperspectral chlorophyll fluorescence spectroscopy is a fast and non-destructive technology allowing early detection of water stress in eggplant plants.

芥菜型油菜黄化突变体叶片叶绿素合成代谢变化

以芥菜型油菜黄化突变体(L638-y)及其野生型(L638-g)为材料,测定了叶片叶绿素(Chl)、类胡萝卜素(Caro)、Chl合成代谢中间产物含量变化,及叶绿素分解代谢的关键酶叶绿素酶(Chlase)和叶绿素合成代谢相关的氨基乙酰脱氢酶(ALAD)、胆色素原脱氨酶(PBGD)、粪卟啉原Ⅲ氧化酶(CPOX)和原卟啉原Ⅸ氧化酶(PPOX)的活性变化,以揭示芥菜型油菜黄化突变体L638-y叶片缺绿的生化机制。结果显示:(1)从油菜苗期到现蕾期,L638-y叶片总Chl和Caro含量均显著低于L638-g,且Chl b含量降低程度大于Chl a,总Chl含量降低程度大于Caro;(2)L638-y叶片Chlase活性在3～5叶期显著低于L638-g,其它各生长时期二者Chlase活性均无显著差异;(3)L638-y叶片叶绿素合成代谢中间产物氨基乙酰丙酸(ALA)、胆色素原(BPG)、尿卟啉原Ⅲ(UrogenⅢ)和粪卟啉原Ⅲ(CoprogenⅢ)含量均显著大于L638-g,而原卟啉Ⅸ(ProtoⅨ)、镁原卟啉(Mg-Proto)、原脱植基叶绿素(Pchlide)的含量却显著低于L638-g;与L638-g相比,L638-y叶片ALAD活性无显著差异,BPGD活性显著增加,而COPX和PPOX活性却显著降低。研究表明,L638-y叶片叶绿素缺乏的主要原因是叶绿素合成代谢受阻,而并非其叶绿素降解所致,受阻位点在由CoprogenⅢ-ProtoⅨ的反应。这是一种不同于前人报道的新型缺绿突变体。

缺钾胁迫对水稻光合特性及光合防御机制的影响

以钾敏感型品种二九丰和钾钝感型品种原丰早为材料,研究了缺钾对水稻光合和叶绿素荧光特性的影响以及光合防御机制,并对缺钾条件下的光合防御机制进行了讨论。在缺钾条件下,两品种的净光合速率(Pn)随气孔导度(Gs)的下降而下降;光合作用的关键酶Rubisco含量降低,而抗氧化酶系统的关键酶SOD活性显著上升。进一步的叶绿素荧光特性研究表明,随着钾胁迫时间的延长,缺钾水稻叶片中的Fv/Fm、ФPSⅡ、qP及ETR均显著下降,说明PSⅡ反应中心受到伤害。缺钾也降低了水稻叶片的光饱和点,PSⅡ吸收的光能超过了光合作用所能利用的光能。缺钾叶片NPQ显著上升,说明钾胁迫下的水稻叶片通过启动热耗散机制耗散过剩的激发能,以减轻因PSⅡ吸收过多光能而引起的光抑制和光氧化从而保护光合机构免受伤害。从品种间的差异来看,原丰早在缺钾条件下,由于仍有较强的光合能力和抗光抑制能力,因此对缺钾有更强的耐性。

水分胁迫下毛竹幼苗光合及叶绿素荧光特性的响应

为分析水分胁迫对毛竹幼苗光合、荧光特性及水分利用效率的影响,以1年生毛竹为试验材料,采用气体交换和叶绿素荧光成像技术,研究不同水分亏缺条件下毛竹幼苗叶片光合生理参数的变化。研究表明:①随着胁迫程度的加深,光系统PSⅡ反应中心活性减弱与光合速率降低一致,气孔限制及PSⅡ反应中心可逆失活或破坏是其净光合速率(Pn)降低的主要原因;②从无胁迫(NS)处理至重度胁迫(HS)处理,光饱和点(LSP)下降20.45%,最大净光合速率(Pnmax)下降67.22%、PSⅡ最大光化学量子产量(Fv/Fm)减少22.46%,有效荧光产量减少45.60%;③低度胁迫(LS)处理水分利用效率较NS处理提高17.81%,光化学淬灭系数(qP)和非光化学淬灭系数(qN)先降低后升高;④初始荧光(Fo)、最大荧光(Fm)、Fv/Fm变异系数均随胁迫处理程度加深而增大,Fo变异区间为18.182%～26.404%,Fm为16.321%～24.899%,Fv/Fm为1.291%～33.932%。