Photosynthesis and water-relation traits of the summer annual C4 grasses, Eleusine indica and Digitaria adscendens, with contrasting trampling tolerance

Two summer annual C₄ grasses with different trampling susceptibilities were grown as potted plants, and diurnal leaf gas exchange and leaf water potential in each grass were compared. The maximum net photosynthetic rate, leaf conductance and transpiration rate were higher in the trampling-tolerant Eleusine indica (L.) Gaertn. than in trampling sensitive Digitaria adscendens (H. B. K.) Henr. Leaf water potential was much lower in E. indica than in D. adscendens. There were no differences in soil-to-leaf hydraulic conductance and leaf osmotic potential at full turgor as obtained by pressure–volume analysis. However, the bulk modulus of elasticity in cell walls was higher in E. indica leaves than in D. adscendens leaves. This shows that the leaves of E. indica are less elastic. Therefore, the rigid cell walls of E. indica leaves reduced leaf water potential rapidly by decreasing the leaf water content, supporting a high transpiration rate with high leaf conductance. In trampled habitats, such lowering of leaf water potential in E. indica might play a role in water absorption from the compacted soil. In contrast, the ability of D. adscendens to colonize dry habitats such as coastal sand dunes appears to be due to its lower transpiration rate and its higher leaf water potential which is not strongly affected by decreasing leaf water content.     

Induced resistance against Alternaria brassicae blight of mustard through plant extracts

An experiment was conducted to study the effect of plant extracts on soluble sugar, soluble phenol and defence-related enzymes response against Alternaria blight in mustard crop. The efficacy of six selected plant extracts (5 and 10%) used as foliar sprays at 60 and 70 days after sowing and mustard leaves was used for investigation. The results indicate that soluble phenol and sugar content in mustard leaves significantly increases in response to spraying of Azadirachta indica seed kernel, Calotropis procera and A. indica leaf extracts. The soluble protein, viz. peroxidase, polyphenol oxidase and phenylalanine ammonia lyase content, was higher in mustard leaves sprayed with C. procera leaves extract, A. indica seed kernel and Allium sativum bulb extract.     

Cadmium accumulation and tolerance of Lagerstroemia indica and Lagerstroemia fauriei (Lythraceae) seedlings for phytoremediation applications

Contamination by heavy metals is one of the most serious environmental problems generated from human activities. Because phytoremediation utilizes plants to uptake contaminants, it could potentially be used to remediate metal-contaminated areas. A pot culture experiment with four levels of cadmium (Cd) (0, 20, 40, and 80 mg of Cd/kg dry soil) was conducted to investigate Cd accumulation and tolerance of roots, shoots, and leaves of Lagerstroemia indica and Lagerstroemia fauriei as well as their potential for phytoremediation. Experimental results indicated that Cd inhibited seedling growth only at the higher Cd exposure concentration (40 and 80 mg/kg). The tolerance index revealed that on average L. indica is more tolerant of Cd than L. fauriei. Moreover, plants in the experiment accumulated Cd differentially. In comparisons between L. indica and L. fauriei, the leaves of the former had higher concentrations of Cd, while the roots of latter had higher concentrations of Cd. Furthermore, the roots, shoots, and leaves had very high bioaccumulation factors that markedly exceeded 1.0 (exceptional only in shoots of 80 mg/kg for L. fauriei), indicating that the seedlings extracted Cd from the soil. The leaves' translocation factor of L. indica was greater than 1.0, being significantly higher than that of L. fauriei. Chlorophyll a, Chlorophyll b and total declined in both species significantly as Cd concentrations exceeded 40 mg/kg in the soil. In contrast, lipid peroxidation and proline content was found to increase with increasing Cd concentration. From the assessments of biomass production, Cd tolerance and uptake L. indica and L. fauriei could stand as excellent species for remediating Cd-contaminated soils.     

Light and sem studies on the life stages of illeis indica (TIMB.) and its predatism on phyllactinia corylea (PERS.) karst. infecting mulberry

The fungivonis insect Illeis indica is a potential biocontrol agent of Phyllactinia corylea which causes powdery mildew in mulberry. The present study by light and scanning electron microscopy explains the life stages of I. indica and its feeding behaviour on P. corylea borne on infected mulberry leaves. The eggs are laid in clusters of 5–23 on the abaxial surface of infected leaves. Each egg has 16–18 aeropyles circularly arranged at its distal end around a micropylar plate. Total larval period of I. indica is about 15.60 days with four instars and its life cycle is completed in 38.50 days. The grubs feed only on conidia during first instar, on conidia and conidiophores during second instar, and also on parts of mycelia during third instar. The final instar grubs feed on entire aerial mycelial mass leaving only stomatopodia and hyphal remnants attached to them. Pupation is for 6–7 days and the pupae remain motionless and attached to the abaxial leaf surface. Adults also feed voraciously on the fungal mass and the fertilized females lay eggs after about 7.03 ±0.144 days. The grubs and adults clear off the fungal mass from the infected leaves without leaving any mycelial patch and the fungus does not regenerate on such cleared leaves. Field observations indicated a drastic fall in the incidence of powdery mildew disease in mulberry even in the usual peak disease period, with the increased population of I. indica in the mulberry garden.     

Chemical characterization of Azadirachta indica grafted on Melia azedarach and analyses of azadirachtin by HPLC‐MS‐MS (SRM) and meliatoxins by MALDI‐MS

Introduction – Melia azedarach adapted to cool climates was selected as rootstocks for vegetative propagation of Azadirachta indica. Cleft grafting of A. indica on M. azedarach rootstock showed excellent survival. Little is known about the chemistry of grafting. Objective – The roots, stems, leaves and seeds of this graft were examined in order to verify if grafted A. indica would produce limonoids different from those found in non‐grafted plants. Intact matured fruits were also studied to verify if they were free of meliatoxins. Methodology – After successive chromatographic separations the extracts afforded several limonoids. HPLC‐MS/MS and MALDI‐MS were used to develop sensitive methods for detecting azadirachtin on all aerial parts of this graft and meliatoxins in fruits, respectively. Results – The stem afforded the limonoid salannin, which was previously found in the oil seeds of A. indica. Salannin is also found in the root bark of M. azedarach. Thus, the finding of salannin in this study suggests that it could have been translocated from the M. azedarach rootstock to the A. indica graft. HPLC‐MS/MS analyses showed that azadirachtin was present in all parts of the fruits, stem, flowers and root, but absent in the leaves. The results of MALDI‐MS analyses confirmed the absence of meliatoxins in graft fruits. Conclusion – This study showed that A. indica grafted onto M. azedarach rootstock produces azadirachtin, and also that its fruits are free of meliatoxins from rootstocks, confirming that this graft forms an excellent basis for breeding vigorous Neem trees in cooler regions. Copyright © 2010 John Wiley & Sons, Ltd.     

Antifungal activity of herbal extracts against plant pathogenic fungi

The present study was designed to evaluate in vitro antifungal activity of herbal extracts against three plant pathogenic fungi (viz. Rhizopus stolonifer, Botrytis cinerea and Colletotrichum coccodes). Extracts of leaves and rinds of Garcinia indica, rhizomes of Curcuma aromatica, roots of Glycyrrhiza gahliae, leaves of Nyctanthes arbour-tristis and seeds of Vernonia anthelmintica were used for screening. Screening was done using poisoned food technique. Relatively potent extracts were shortlisted from this study and were further assayed to find out their minimum fungicidal concentration (MFC). From the above studies, it was observed that ethyl acetate extract of rhizomes of C. aromatica and unripe fruit rinds of G. indica have shown the lowest MFC values amongst the other tested plant extracts. This study indicates that the potential of these plant extracts in the management of diseases caused by plant pathogenic fungi.     

Impact of Piriformospora indica on tomato growth and on interaction with fungal and viral pathogens

Piriformospora indica is a root endophytic fungus with plant-promoting properties in numerous plant species and induces resistance against root and shoot pathogens in barley, wheat, and Arabidopsis. A study over several years showed that the endophyte P. indica colonised the roots of the most consumed vegetable crop tomato. P. indica improved the growth of tomato resulting in increased biomass of leaves by up to 20%. Limitation of disease severity caused by Verticillium dahliae by more than 30% was observed on tomato plants colonised by the endophyte. Further experiments were carried out in hydroponic cultures which are commonly used for the indoor production of tomatoes in central Europe. After adaptation of inoculation techniques (inoculum density, plant stage), it was shown that P. indica influences the concentration of Pepino mosaic virus in tomato shoots. The outcome of the interaction seems to be affected by light intensity. Most importantly, the endophyte increases tomato fruit biomass in hydroponic culture concerning fresh weight (up to 100%) and dry matter content (up to 20%). Hence, P. indica represents a suitable growth promoting endophyte for tomato which can be applied in production systems of this important vegetable plant not only in soil, but also in hydroponic cultures.     

印度梨形孢对铁皮石斛种子萌发和原球茎生长的影响

为探究印度梨形孢(Piriformospora indica)对铁皮石斛(Dendrobium officinale)种子萌发和原球茎生长的影响,在铁皮石斛种子离体培养和原球茎生长阶段分别接种印度梨形孢,对其形态发育特征和生理特性进行研究.结果表明,接种印度梨形孢的铁皮石斛种子的起始萌发时间提前,接种印度梨形孢的铁皮石...     

Antibacterial activity of herbal extracts against five plant pathogenic bacteria

The present study was designed to evaluate in vitro antibacterial activity of herbal extracts against five plant pathogenic bacteria (viz. Xanthomonas campestris, Xanthomonas axonopodis pv. punicae, Erwinia spp., Pseudomonas syringae and Xanthomonas citri). Herbal extracts of leaves and rinds of Garcinia indica, rhizomes of Curcuma aromatica, roots of Glyccyrrhiza glabra, leaves of Nyctanthes arbor-tristis and seeds of Vernonia anthelmintica were used for screening. Screening was done using agar well diffusion method. Relatively potent extracts were shortlisted from this study and were further studied to find out their minimum bactericidal concentration (MBC). From the studies, it was observed that extracts of C. aromatica, G. indica and G. glabra have shown lowest MBC values among other tested plant extracts. This study indicates the potential of these potent plant extracts in the management of diseases caused by plant pathogenic bacteria.     

First Report of Botryosphaeria dothidea on Mangifera indica L. in Gujarat

A leaf spot disease was observed on Mangifera indica L. located in the region of Rajkot, Gujarat, India. The symptoms included the appearance of small, circular to oval dark brown necrotic sunken spots on the leaves. The fungus formed grey to dark grey on potato dextrose agar and conidia were single‐celled, ovoid or oblong. On the basis of mycological characteristics, pathogenicity test and molecular identification using 28S rDNA sequence and internal transcribed spacer (ITS), the fungus was identified as Botryosphaeria dothidea. To the best of our knowledge, this is the first report of leaf spot on M. indica tree caused by Botryoshaeria dothidea in Gujarat, India.     

Frerea indica,a stem succulent CAM plant with deciduous C3 leaves

Summary During the winter in greenhouse culture, Frerea indica(Asclepiadaceae) is a leafless stem succulent resembling the other members of the Stapelieae subfamily. However, in spring it produces leaves which persist during the summer period. CO₂ exchange measurements were carried out with Frerea indica at its different seasonal states of development. The leafless stems in winter as well as the defoliated ones in summer show all characteristics of Crassulacean acid metabolism. The leaves, on the other hand, fix CO₂ with high rates according to the C₃ pathway; no diurnal malate fluctuations are detectable. This feature can be interpreted as an ecological adaptation where a seasonal plant dimorphism enables a functional change in the prevailing mode of CO₂ metabolism. In the leafless state, which probably represents the appearance of the plant during the dry period in nature, it is saving water by pursuing CAM. The season with enough water available can be used for high photosynthetic gain by C₃ leaves.     

Habitat preferences of four chironomid species associated with aquatic macrophytes in an irrigation reservoir

Habitat preferences of four chironomid species associated with aquatic macrophytes were studied during the vegetation season from April to October at an irrigation reservoir located in Nagoya, Japan.The two smaller sized species,Corynoneura cuspis Tokunaga andPentapedilum tigrinum Hashimoto, were found to be abundant in two floating-leaved plants,Nymphoides indica O. Kuntze andTrapa japonica Flerov. Phytophages,C. cuspis larvae were observed freely moving on the surfaces of leaves and stems within both of these floating-leaved plant communities. Although found within both plant communities,P. tigrinum larvae, as facultative leaf miners, were more concentrated on the surfaces and within the leaves ofN. indica, which have a thin epidermis and thick mesophyll layer.The two larger sized species,Glyptotendipes viridis (Macquart) andPentapedilum sordens (van der Wulp), were found to be living principally within the stems ofN. indica and the petioles ofT. japonica. These parts of the plants, with thin epidermis and many lacunae in the parenchyma, are favorable for miners.     

Biological activity of essential oils from seven Azorean plants against Pseudaletia unipuncta (Lepidoptera: Noctuidae)

Ten essential oils from seven Azorean plant species were evaluated for their insecticidal, ovicidal, feeding‐deterrence and growth inhibition activities against Pseudaletia unipuncta. The oils of Laurus azorica (leaves), and Juniperus brevifolia (leaves) showed strong moderate insecticidal effect on fourth‐instar larvae causing 93.3% and 46.7% mortality, respectively. Juniperus brevifolia (leaves), L. azorica (leaves), Persea indica (leaves), Hedychium gardnerianum (leaves) and Pittosporum undulatum (fruits and leaves) significantly affected the hatching of P. unipuncta eggs (<8% eclosions). Five oils showed significant feeding deterrent activities (L. azorica, 92.4%, J. brevifolia, 93.6%, P. undulatum leaves, 95.5% and fruits, 83.8% and H. gardnerianum, 88.2%). All of the essential oils tested, significantly inhibited the larval growth after 5 days of feeding on the treated diet. Essential oils from L. azorica and J. brevifolia were the most potent growth inhibitors among the oils tested, producing a decrease in the initial larva weight (?14.8 and ?14.5 mg, respectively). Our results indicate that L. azorica (leaves), J. brevifolia (leaves), P. indica (leaves), H. gardnerianum (leaves), and P. undulatum (leaves and fruits) can be exploited for the development of bioactive compounds as a new source of agrochemicals. Further emphasis on isolation and identification of active constituents can be useful to develop new environment‐friendly insect control agents.     

Euphorbia cotinifolia (Euphorbiaceae): a promising alternative for leaf cutting ant Atta cephalotes (Hymenoptera: Formicidae) control

Field observations indicate that Euphorbia cotinifolia escapes attack by leaf cutting ants, which are the largest generalist herbivores of the Neotropics. We used controlled bioassays to evaluate the effect of E. cotinifolia on the foraging of the Atta cephalotes ant. In a free-choice trial, to five colonies were offered Mangifera indica leaves with a 10% aqueous E. cotinifolia extract, leaves with distilled water and untreated leaves. The carrying time and leaf area consumed were determined over a five-hour period. The effect of E. cotinifolia on the development of the symbiotic fungus on three sets of five colonies fed the leaves of this plant were compared to the controls fed M. indica and oat flakes, and the effect of the addition of extracts on the culture medium used for the symbiotic fungus isolation was evaluated. Euphorbia leaf consumption was lower than that of the other diets; its consumption as the exclusive foraging resource significantly affected the symbiotic fungus, resulting in changes in colour and texture and an 83.57% decrease in volume that occasionally caused 100% mortality. Although the aqueous extract of E. cotinifolia is not a phagodeterrent for foraging workers, it is evident that E. cotinifolia is not a preferred resource for A. cephalotes due to the negative effect on the growth and viability of the symbiotic fungus.     

Differences in Field Gas Exchange and Water Relations Between a C3 Dicot (Plantago Asiatica) and a C4 Monocot (Eleusine Indica)

Field gas exchange and water potential in the leaves of a C₃ dicot, Plantago asiatica L., and a C₄ monocot, Eleusine indica Gaertn., which dominate in trampled vegetation in eastern Japan were surveyed during the growing periods for two consecutive years. Net photosynthetic rate (P _N) of E. indica increased with photosynthetic photon flux density (PPFD) and leaf temperature (T_L). P _N was not saturated at PPFDs above 1500 μmol m⁻² s⁻¹ and at T_L above 30 °C. On a sunny day in mid summer, maximum P _N was two times higher in E. indica than in P. asiatica [42 vs. 20 μmol(CO₂) m⁻² s⁻¹], but their transpiration rate (E) and the leaf water potential (Ψ_L) were similar. Soil-to-leaf hydraulic conductance, which probably plays a role in water absorption from the trampled compact soil, was higher in E. indica than in P. asiatica. The differences in photosynthetic traits between E. indica explain why E. indica communities more commonly develop at heavily trampled sites in summer than the P. asiatica communities. This revised version was published online in June 2006 with corrections to the Cover Date.     

Guignardia citricarpa a Cause of Black Spot on Mango Foliage in Florida1

A strain of Guignardia citricarpa Kiely was isolated from infected mango (Mangifera indica L.) leaves. The morphological and physiological characteristics of perithecia and ascospores were identical with those described for G. citricarpa. Inoculated leaves developed lesions 7 to 10 days after ascospore germination. Young lesions appeared as minute, sunken, blackish depressions on upper and lower leaf surfaces. Mature lesions were roughly circular ranging from 1 to 2 mm in diameter. The fungus was consistently reisolated from the lesions which appeared on the leaves, arising from inoculation. Benomyl at 1.7 g/l provided control of black spot.     

Studies on fungal diseases of some tropical fruits IV. Some new fungi

Summary Four new species which includedSordaria allahabadensis on flowers ofCarica papaya L.,Thielavia appendiculata on leaves ofPunica granatum L.,Phomopsis amraii on leaves ofMangifera indica L. andPhoma punicae on twigs ofPunica granatum L. have been described.     

六种园林植物耐旱性分析

为选择耐旱性较强的园林绿化植物,选择6种常见的园林植物：金银木（Lonicera maackii）、紫荆（Cercis chinensis）、紫薇（Lagerstroemia indica）、荆条（Vitex negundo var.heterophylla）、胡枝子（Lespedeza bicolor）和构树（Broussonetia papyrifera）,进行盆栽控水试验,对植株外观形态和土壤含水率、叶片叶绿素含量、超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量进行比较。结果表明,随干旱胁迫时间的延长,土壤含水量均呈下降趋势,金银木、胡枝子和荆条的长势较好;紫薇、紫荆和构树出现叶片萎蔫、掉落现象,6种植物叶片的光合色素含量呈先上升后下降的趋势,除紫薇外,SOD活性总体均呈上升趋势,MDA含量持续上升。可见,金银木、胡枝子和荆条的耐旱性较强,紫薇、紫荆和构树的耐旱性较弱。