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Sclerotium rolfsii is a necrotrophic, soil-borne pathogenic fungus responsible for serious crop losses worldwide. It is one of the major phytopathogens infecting chilli and causes yield losses ranging from 16 to 80%. Among the various approaches to manage S. rolfsii, biological control is an environmentally acceptable alternative over other chemical methods. In this study, 120 endophytic fungal isolates obtained from a medicinal plant, Nothapodytes nimmoniana were evaluated for their in vitro and in vivo antagonism towards S. rolfsii. Among these, one isolate, Alternaria sp. exhibited 46.62% inhibition against S. rolfsii in dual culture assay on PDA. The inhibition was found to be mediated by the mycotoxin, tenuazonic acid, produced by the endophyte. Pre-germinated chilli seeds treated with mycelial suspension of Alternaria sp. reduced the seedling mortality due to S. rolfsii infection. Pretreatment with the endophyte also enhanced seedling growth and biomass compared to untreated seedlings under greenhouse conditions. These results suggest that the endophytic fungus, Alternaria sp. has potential implication for use as a biocontrol against S. rolfsii as well as for promoting growth of chilli.

Alternative splicing (AS) of transcripts is a well-recognized phenomenon in plants. Several studies have shown that the frequency of AS events are significantly enhanced in plants subjected to abiotic stresses, presumably as an adaptation to increase transcript diversity. In this study, we examine the effect of a salt tolerant endophytic fungus, Fusarium sp. on the AS events of IR-64 rice plants, under salinity stress. RNA seq data generated from rice plants, treated and not treated with Fusarium sp. respectively and subjected to 150 mM salinity stress was used to analyze the number and type of AS events and their chromosomal distribution using approriate bioinformatics pipeline. Besides, we also annotated the locus IDs of genes for gene enrichment and KEGG pathway analysis. Our results show an unequivocal decrease in the number of AS events under salinity stress as influenced by the endophyte. The average AS events per gene also decreased from 2.28 to 2.11 upon colonization by the endophyte. This is the first documented evidence of an endophyte-induced alteration in the frequency of alternative splicing event in plants subjected to salinity stress. The exact mechanisms through which the splicing activities are restrained, however need to be further investigated.

Colchicine, a well-known alkaloid, is a potent inhibitor of polymerization of tubulin leading to mitotic arrest. It is highly toxic to eukaryotic cells but also widely used in the field of medicine and plant breeding. Gloriosa superba (family: Colchicaceae) is an important natural source of colchicine. The seeds, tubers and leaves of this plant contain about 0.8, 1.2 and 0.014% colchicine by dry weight respectively. A noctuid moth, Polytela gloriosae (family: Noctuidae), feeds voraciously on leaves of G. superba without any adverse effect. However, the fate of colchicine and the mechanisms by which the insect is able to overcome the toxicity of the metabolite is not known. Here, we trace the fate of colchicine in both, the larva and moth of P. gloriosae. Colchicine was quantified in different body parts of the larvae and moth by high performance liquid chromatography, liquid chromatography mass spectrophotometry and nuclear magnetic resonance methods. Of the total colchicine taken in by the larva, a larger portion was excreted, while the rest was sequestered in its cuticle. In the moths however, the wings, legs and antennae were found to accumulate high amount of colchicine. The sequestered colchicine, in both the larva and adult, were chemically identical to that found in the plant. Negligible amounts of demethyl-(−)-colchicine, a less toxic derivative of colchicine was also detected. We discuss the probable adaptive significance of sequestration of colchicine by the insect.

Camptothecin (CPT), a monoterpene indole alkaloid, is a potent inhibitor of eukaryotic topoisomerase I (Top 1). Because of this property, several derivatives of CPT are widely used as chemotherapeutic agents. The compound is produced by several plant species, including Nothapodytes nimmoniana (Family: Icacinaceae) presumably as a deterrent to insect pests. Here, we report, a lepidopteran larva, Lymantria sp. of Lymantriidae family which feeds voraciously on the leaves of N. nimmoniana, without any adverse consequences. Larval body weight and molting period were unaffected despite captive feeding of the larva with CPT enriched leaves. Mass spectrometric analysis indicated that nearly 46% of the ingested CPT was excreted while the rest was sequestered predominantly in the exuviae and setae (~35%). Although most of the CPT was in the parental form as found in the plant, traces of inactive, sulfated forms of CPT were recovered from the larva. Compared to that in plant, there were no critical mutations at the CPT binding domain of the insect's Top 1. The gut pH of the larva was alkaline (pH 10.0). The alkaline gut environment converts CPT from its active, lactone form to inactive, carboxylate form. It is likely that such conversion might help the larva to reduce the overall burden of CPT in its gut. We discuss the results in the context of the mechanisms of resistance adapted by insects to plant toxins.

A total of 507 endophytic fungal isolates belonging to 82 operational taxonomic units (OTUs) were isolated from fifteen plant species naturally occurring in the Thar Desert, Rajasthan, India. Aspergillus, Alternaria, Chaetomium, Penicillium and Nigrospora were among the dominant fungal genera. Thermotolerance of the isolates was evaluated by culturing the fungi at 40 °C and 45 °C in shake flasks. Growth of nine OTUs (ACJ-2, ACJ-5, ACL-2, ACT-2, ACT-3, LAS-4, LAS-6, SAP-3 and SAP-6) was unaffected at 40 °C. Of these, six endophytes, namely, ACJ-2, ACJ-5 (Aspergillus flavus), SAP-3 (Aspergillus sp.), SAP-6, LAS-4 (Aspergillus sp.) and LAS-6 (Chaetomium sp.), were tolerant to as high as 45 °C. Rest of the OTUs did not survive culture temperatures beyond 35 °C. We evaluated the ability of one thermotolerant endophyte, LAS-6 (Chaetomium sp.) to confer high temperature tolerance and three OTUs, namely, LAS-4 (Aspergillus sp.), SAP-3 (Aspergillus sp.) and SAP-6 to confer drought tolerance to a rice cultivar, IR-64, at early seedling stage. Seedlings treated with LAS-6 (Chaetomium sp.) showed a higher survival percentage as well as maintained a significantly higher shoot and root growth under high temperature stress compared to seedlings not treated with the fungus. Under drought stress, endophyte treated seedlings maintained a significantly higher root growth compared to untreated seedlings. The identified thermotolerant fungal sources could be potentially useful in alleviating abiotic stress in agriculturally important crops.

The global economy of the international trade of herbal products has been increasing by 15% annually, with the raw material for most herbal products being sourced from South and Southeast Asian countries. In India, of the 8000 species of medicinal plants harvested from the wild, approximately 960 are in the active trade. With increasing international trade in herbal medicinal products, there is also increasing concern about the widespread adulteration and species admixtures in the raw herbal trade. The adverse consequences of such species adulteration on the health and safety of consumers have only recently begun to be recognised and documented. We provide a comprehensive review of the nature and magnitude of species adulteration in the raw herbal trade, and identify the underlying drivers that might lead to such adulteration. We also discuss the possible biological and chemical equivalence of species that are used as adulterants and substitutes, and the consequences thereof to consumer health and safety, and propose a framework for the development of a herbal trade authentication service that can help regulate the herbal trade market.

Lawsone (2-hydroxy-1, 4-napthoquinone), also known as hennotannic acid, is an orange red dye used as a popular skin and hair colorant. The dye is produced in the leaves of Lawsonia inermis L, often referred to as the "henna" tree. In this study, we report the production of lawsone by an endophytic fungus, Gibberella moniliformis isolated from the leaf tissues of Lawsonia inermis. The fungus produced the orange-red dye in potato dextrose agar and broth, independent of the host tissue. Presence of lawsone was confirmed spectrometrically using HPLC and ESI-MS/MS analysis. The fragmentation pattern of lawsone was identical to both standard lawsone and that extracted from plant tissue. This is a first report of lawsone being produced by an endophytic fungus, independent of the host tissue. The study opens up interesting questions on the possible biosynthetic pathway through which lawsone is produced by the fungus.

In nature, plants and microorganisms interact constantly to modulate their growth and development. The interaction could be beneficial or hostile. Plants are constantly exposed to a range of pathogens, and have evolved mechanisms to fight the pathogen infections with the help of complex networking pathways. In addition to the pathogens, many beneficial organisms such as endophytes, of both, bacterial and fungal origin, are ubiquitously present in all plants. Unlike from their pathogenic counterparts, the endophytes do not cause any disease symptoms in their host plants. Some of the recent scientific discoveries and views concerning plant–microbe interactions are presented here.

A number of studies have shown that there could be widespread substitution and/or adulteration (hereafter referred to as substitution) in raw herbal trade of medicinal plants. Substitution could potentially endanger the health and safety of the consumers. In this study, the extent of adulteration in raw herbal trade of 30 important medicinal plants in South India was analyzed. Biological reference material (BRM) consisting of taxonomically authenticated samples of each of the 30 species along with 14 other co-occurring and congeneric allied species that are likely to be used in adulteration was established. DNA barcode signatures of 124 BRM using two candidate regions, nr-ITS and psbA-trnH were identified. A total of 203 herbal trade samples representing the 30 medicinal plant species were collected from 34 locations in South India. Using the DNA barcode sequences of the BRM as reference, the analysis indicated that the substitution ranged from 20 to 100%. Overall, approximately 12% of the market samples were adulterated. Considering the potential health hazard that such adulteration can cause, the need for a national regulatory framework that can authenticate and regulate raw herbal trade in the country is discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-018-1169-3) contains supplementary material, which is available to authorized users.

Tropical agro-forest landscapes are potentially valuable reserves of forest genetic resources for forestry and restoration of degraded forests. The Dipterocarpaceae is a dominant Southeast Asian family of tree species of global significance for the tropical timber industry. Very little information exists about how effective human modified landscapes are for conserving genetic diversity in dipterocarp species. This study provides a baseline for understanding how fragmented agro-forest landscapes in India sustain forest genetic resources in an endemic dipterocarp tree. We compare genetic diversity and fine-scale spatial genetic structure (FSGS) in the threatened tree species Vateria indica within an isolated and a continuous forest site in the Western Ghats, South India. We place these results in the context of dipterocarps from both the Seychelles and Borneo. Parentage analysis of 694 progeny using twelve nuclear microsatellite markers is applied to estimate pollen and seed dispersal. Using a nursery trial we evaluate effects of inbreeding on growth performance. Our results show that levels of FSGS, and gene dispersal are comparable between a small isolated and a large continuous site of V. indica. Realized long-distance pollen flow into the isolated patch appears to help maintaining genetic diversity. The nursery experiment suggests that selection favours outbred progeny. Individuals of V. indica in close proximity appear less related to each other than in another highly fragmented and endangered dipterocarp species from the Seychelles, but more related than in three dipterocarp species studied in continuous forest in Borneo. We discuss the wider implications of our findings in the context of conservation and restoration of dipterocarp forest genetic resources in fragmented populations.

Lantana camara. L (hereafter Lantana) was first introduced by the British into India in 1807 as an ornamental plant. Since then the species has spread across the length and breadth of the country. Attempts to control Lantana in India have not been successful. In this study, we analysed the use of Lantana by local communities in southern India and identified the possible causes and consequences of its use through the use of a household survey of the socio-economic profile of the user and nonuser households and an analysis of the ecological history of the communities. Communities have been using Lantana for over 25–30 years and apparently such use was not prompted by external agencies. The characteristics of user and nonuser households were similar, except that Lantana users were more literate and had a greater number of occupations per household than nonusers. Per capita income was similar between user and nonuser groups. For nonuser groups, their main income sources were from trading (44 %), wage labour (32 %) and forest resources (23 %). In contrast, the Lantana user groups substituted their loss of income from forest resources (7 %) by income from Lantana (46 %). The ecological history revealed that Lantana was adopted as a resource at a time when it was increasing in the landscape and traditional bamboo resources were in decline because of overuse by commercial enterprises and mast flowering. This change in ecological resource availability prompted a major shift in livelihoods for some in the area.

We compared morphological and genetic attributes of progeny obtained from three seed production areas (SPAs) and three corresponding unimproved stands (UIS) of teak (Tectona grandis L.f) at three broad teak growing regions in the state of Karnataka, India. In general, seed morphological parameters such as seed weight, seed size and seed emptiness were significantly superior in SPAs compared to UISs. Seed germination percentage was also higher in seeds from SPAs. Seedling performance measured at two monthly intervals for six months was observed to be superior in SPAs at two of the three regions compared. Although the genetic diversity of progeny of SPAs was lower than UIS at all regions, the values were moderately high. Germination percent was positively correlated with fruit weight and kernel weight per seed, while diversity indices were negatively correlated with fruit weight, fruit diameter and kernel weight per seed. SPAs proved important as a source of moderately improved planting material with no severe threat to the genetic diversity of future plantations.

1Ashoka Trust for Research in Ecology and the Environment, Royal Enclave, Srirampura, Jakkur Post, Bangalore 560 064, India 2School of Ecology and Conservation, University of Agricultural Sciences, GKVK Campus, Bangalore 560 065, India 3Department of Crop Physiology, University of Agricultural Sciences, GKVK Campus, Bangalore 560 065, India 4Department of Forest Biology and Tree Improvement, College of Forestry, University of Agricultural Sciences, SIRSI campus, Dharwad 581 401, India

Teak (Tectona grandis L. f.; family Verbanaceae) is an important plantation tree species in the tropics and in India one of the first species to be prioritized for improvement. Improvement efforts for the last 50 years have essentially concentrated on augmenting quality seed production by establishing seed production areas (SPA) and clonal seed orchards (CSO). Presently, these two form the main sources of quality planting material for teak throughout the country. However, there is no information on the genetic quality of such sources nor information on the progeny used in plantation programmes. Reports of studies based on coniferous and tropical species provide conflicting results on the impact of domestication on the genetic diversity of populations (Chaisurisri and El Kassaby 1994; Rajora 1999; Moran et al. 2000; Godt et al. 2001; Icgen et al. 2006). Also the impact of domestication on the genetic diversity of progeny populations is poorly understood (Stoehr and El-Kassaby 1997; Schmitdtling and Hiplins 1998). Such studies become pertinent not only for gauging the impact of selection on reforestation stock, but also for effective genetic conservation of existing breeding populations. We therefore address two issues in the present study: (i) the change in genetic diversity with increasing levels of improvement, and (ii) the impact of the above change on genetic diversity of progeny populations.

This study sought to reconstruct the history of Lantana invasion and spread in India by considering two questions; (a) from where, by who, and when were Lantana species introduced into India? and (b) given its long history in the country, is it still spreading or more or less stable? We critically evaluated the archival and historical information on plant imports by the European powers into India during the period before and after British colonization. We then reconstructed the path of spread by analyzing the spatio-temporal patterns of occurrence and distribution of Lantana in India at both the national and local scale using a GIS platform. The spread of Lantana across the globe started as early as the 1690s. The European colonial powers moved the plants from Latin America to Europe and to their colonial countries in the early 1800s. Lantana species were introduced in India from 1807 onwards and thereafter the colonial powers moved this plant across the country. Following its introduction into India, the spread of Lantana across the country, either through subsequent multiple introductions from Europe to different British cantonments, or through moving the plants between cantonments within India, were reasonably rapid spanning only a few decades. In the absence of a rigorous control program, the spread of Lantana has gone on unabated and thereby impacting both wildlife and biodiversity.

Santalum album L. is an economically important tropical tree species. Owing to extensive logging, changes in land-use patterns and poor natural regeneration, the natural sandal populations are rapidly dwindling. It is feared that such threats could easily undermine the genetic diversity of sandal populations. Effective measures to prevent such loss are prerequisite. We have developed baseline data on the levels of genetic diversity and its distribution on a geographic scale for sandal in India. Based on Geographic Information System, distribution map of sandal was developed and found that the populations were geographically more concentrated in the Deccan plateau. It was found that, for past 53 years, there was a monotonic decrease in the extraction of sandal in the state of Karnataka, India. Using allozyme markers, the genetic diversity of 19 sandal populations in peninsular India were determined and over all observed heterzygosity (Ho) was found to be 31%. The percent Ho was positively correlated with the density of the sandal populations (r = 0.44) and with increasing longitude it was found to be negatively correlated (r = −0.51). The dendrogram analysis indicated a clear clustering of sandal populations based on their geographic occurrence. The Deccan plateau populations were found to be genetically the most diverse and seemed to represent the ‘hot-spot’ of sandal genetic resources in peninsular India. Our results have important implications for the conservation strategies for sandal populations in peninsular India and can be applied for the conservation of other taxa as well.

1Conservation Genetics, Ashoka Trust for Research in Ecology and the Environment, Royal Enclave, Srirampura, Jakkur Post, Bangalore 560 064, India 2School of Ecology and Conservation, 3Department of Crop Physiology, University of Agricultural Sciences, GKVK Campus, Bangalore 560 065, India 4Biology Department, Concordia University, 7141, Sherbrooke Street West, Montreal, Canada H4B1R6 5Department of Forest Biology and Tree Improvement, College of Forestry, University of Agricultural Sciences, SIRSI campus, Dharwad 581 401, India

Conservation Genetics Resources, 5 (2), ISSN:1877-7252, ISSN:1877-7260

Lantana camara is a highly invasive plant that has established itself in at least 60 different countries across the world. Here, we report development of ten microsatellite markers for this species. These microsatellite loci have 2–15 alleles per locus; with observed and expected heterozygosity of 0.022–0.833 and 0.336–0.848, respectively. These markers will be useful in addressing a variety of questions about Lantana camara, including those concerning breeding system, pollination and dispersal, genetic variation and population structure.

The Myristicaceae family is a primitive angiosperm family and is characterized by species that are highly endemic to the Western Ghats area of India. Myristica malabarica is confined to the evergreen forests of Western Ghats and Sri Lanka. In this paper we describe for the first time the development of eleven polymorhpic microsatellite markers for Myristica malabarica, which had 2-14 alleles per locus. These microsatellite markers could be used to study the population genetic structure of the species.

Ideally, the estimates of biological diversity of a community of species in a habitat should refer to the biological variation among the species and not merely to their numbers and frequencies. However, the current estimates of biodiversity incorporate only the latter two components but not the biological differences among the species. Ganeshaiah et al. [(1997) Current Science 73: 128–133] have proposed an estimate called the Avalanche Index (AI) that can incorporate the biological heterogeneity among the species in a habitat. This estimate, besides being methodologically simple, can incorporate any quantifiable differences among the species, information on species richness and their frequencies in the habitat. In this paper we have estimated AI for tree vegetation in 14 forest types across different ecosystems of the world and have compared these estimates with other indices being currently used. Through this we have attempted to analyse the relative utility of AI in discriminating the habitats based on their biological heterogeneity by capturing their intra-community biological variation. We discuss the merits and demerits of the AI as a comprehensive estimate of biological diversity.

Ceropegia fantastica L. (Asclepiadaceae) is a highly endemic and endangered species in the Western Ghats of India. Fourteen microsatellite markers were developed for C. fantastica. Eight microsatellite primers screened had 2–5 alleles per locus and the observed and expected heterozygosity ranged from 0.48 to 0.83 and 0.48 to 0.62, respectively. The primers were also evaluated for their cross amplification against two related species Ceropegia hirsuta and Ceropegia oculata. The microsatellites developed for this species could be used for addressing population genetics of this endemic and critically endangered species.

Dalbergia sissoo, a tropical tree with wind-dispersed pods, exhibits a highly positively skewed distribution of seeds per pod with predominantly only one of the four or five ovules maturing into seed. The abortion cannot be attributed to lack of pollen or resources. This study examines the hypothesis that the abortion is due to an intense rivalry among the developing sibs to gain dispersal advantage. Aqueous extract of the dominant embryos at the stigmatic end that generally develop to maturity significantly inhibited the uptake of labelled sucrose by the young developing (subject) embryos in an in vitro assay system. Extracts of tissues such as subordinate (peduncular embryos), unfertilized ovules and pod coat did not cause such inhibition. Aqueous diffusate of dominant embryos also inhibited the uptake of labelled sucrose by subject embryos. The chemical substance responsible for the inhibition appears to be heat-stable and non-proteinaceous. HPLC analysis indicated the presence of two retention time peaks, different from that of standard indole acetic acid, but with considerable overlap. We hypothesize that the compound could be an indole derivative. We propose that the stigmatic embryos have a head start due to earlier fertilization and produce a chemical that either directly (by metabolically killing) or indirectly (by preventing the uptake of assimilates) kills the proximally placed peduncular embryos.

Sustainable extraction of non-timber forest products (NTFPs) has recently gained considerable attention as a means to enhance rural incomes and conserve tropical forests. However, there is little information on the amounts of products collected per unit area and the impact of extraction on forest structure and composition. In this paper we estimate the quantities of selected products gathered by the Soligas, the indigenous people in the Biligiri Rangaswamy Temple (BRT) sanctuary in Karnataka, India, and examine the effect of extraction on forest structure and composition. Two sites, distant (DS) and proximal (PS), were identified based on the proximity to a Soliga settlement. The frequency of different size classes indicates that regeneration overall is poor in the area. The two sites show differences in species richness, basal area, and tree mortality. Furthermore, non-timber forest product species show a greater deficit of small size classes than the timber forest species, suggesting that regeneration is affected by collection of seeds and fruits from non-timber forest product species. Regeneration, however, may also be affected by other anthropogenic pressures such as fire, grazing and competition with weeds.

Sustainable extraction of non-timber forest products (NTFPs) depends upon harvesting a small fraction of the total productivity. Over-exploitation can lead to a loss of biodiversity, but a low level of extraction, without value addition at the point of origin, is usually not economically feasible for extractors. Extraction and productivity levels per unit area for most non-timber forest products are unknown, nor do we have much information about value addition at various points in the marketing channels. Here we determine extraction and productivity levels for Amla trees (Phyllanthus emblica), which yield fruits that are used for a wide variety of purposes in preparation of various foods, beverages and medicines. We also present preliminary data on the price appreciation of the fruit for one of the processed products. We have determined that the current level of extraction, 60-80% of all fruits at the population level, may have a negative effect on new recruitment. We present a model for value addition that has the potential to enhance income and reduce the level of extraction. This model is currently being implemented by the Soliga community with the assistance of a non-governmental organization.

The evolution of endosperm, the tissue that nourishes developing embryos, has remained an enigma owing to its unique genetic composition. Because it contains both maternal (generally 2 doses) and paternal (1 dose) genomes, it is suggested to have evolved as a compromising tissue between the evolutionary interests of the maternal parent and offspring over resource allocation. This argument implies that in species where endosperm is highly functional and persistent, it quenches competition among developing embryos for resources and facilitates an equitable resource allocation to the developing offspring. Based on this argument we predict the association of well developed endosperm with certain features of fruits such as high ovule number per ovary and low extent of seed abortion. In this paper, we provide evidence in support of these predictions by analysing the data from 1131 species from the Flora of Presidency of Madras. We show that persistent and functional endosperm is more frequent in multiovulated than in uniovulated species and in species with less seed abortion. Our results also suggest that species with well developed endosperm tend to have uni-carpelled ovaries. Our analyses show that these associations are less likely to be emerging due to phylogenetic constraints. We argue that the endosperm has evolved as a maternal strategy of quenching the extent of sibling rivalry.

Monoecious figs reward their pollinators—agaonid wasps—by allocating a proportion of the flowers for egg laying, and retain the rest for seed production. It has been suggested that these proportions could be regulated by producing short-styled and long-styled flowers such that pollinator wasps could only use the former as their ovipositor does not reach the ovules of the latter. Thus the wasps can lay eggs only in the short-styled flowers and raise their offspring, and the ovules of uninfested, long-styled flowers can develop into seeds. This implied that figs bear dimorphic female flowers, with a bimodal distribution of style length. However, recent studies have shown that style length is distributed normally, with no evidence of bimodality. Therefore the regulation of allocation of flowers to the wasps does not seem to be through the production of two distinct kinds of female flowers. In this article we suggest that two factors govern the proportion of flowers rewarded to the wasps: (i) passive regulation, which is a consequence of the optimization of wasp ovipositor length, and (ii) active regulation, where figs are selected to enhance the variance of style length. We show that these arguments lead to certain predictions about the optimum ovipositor length, the proportion of the flowers available to the wasps, and the coefficient of variation of style length. We also show that data for 18 fig-wasp associations conform well with these predictions. We finally suggest that the regulatory process outlined here can be extended to evolution of style length in dioecious fig species also.

It is suggested that maternal parent and offspring have conflicting interests over the extent of resource allocation to developing seeds. While maternal parent would be selected to allocate her resources optimally among her offspring, the latter would be selected to demand more. In animals, offspring are known to demand additional resources either visibly (through intense vocal calls) or subtly through the production of hormones. In plants though parent offspring conflict over resource allocation has been invoked, the mechanism through which the parent and offspring interact in regulating resource allocation into developing seeds is not yet clear. In this paper, we propose that the strategies and counter-strategies of the offspring and mother during the development of seeds might be manifested through the production of appropriate growth hormones. Accordingly, we predict (i) hormones that mobilize resources into seeds (e.g. auxins and gibberellic acid) shall be synthesized exclusively by the offspring tissue and (ii) hormones that inhibit resource flow in to seeds (e.g. abscisic acid) be produced exclusively by the maternal tissue. We show that these predictions are supported by existing literature on the temporal dynamics and source of production of growth hormones during seed development. Finally, we suggest that such analysis viewing the production of different hormones during early seed development, as strategies and counter-strategies of mother and offspring tissue, helps ofer a meaningful interpretation of the otherwise complex dynamics of hormone fluxes.

In view of the recent debate on the future of invasion biology, we argue that species could be regarded as invasive only when after adaptation in non-native habitats they reach yet another fitness maximum. We suggest that invasion biologists need to unambiguously clarify what constitutes being “invasive” to refute those who call for an end to invasion biology.

Polyembryony, referring here to situations where a nucellar embryo is formed along with the zygotic embryo, has different consequences for the fitness of the maternal parent and offspring. We have developed genetic and inclusive fitness models to derive the conditions that permit the evolution of polyembryony under maternal and offspring control. We have also derived expressions for the optimal allocation (evolutionarily stable strategy, ESS) of resources between zygotic and nucellar embryos. It is seen that (i) Polyembryony can evolve more easily under maternal control than under that of either the offspring or the ‘selfish’ endosperm. Under maternal regulation, evolution of polyembryony can occur for any clutch size. Under offspring control polyembryony is more likely to evolve for high clutch sizes, and is unlikely for low clutch sizes (

Proteinase inhibitors (PI) occur ubiquitously across microorganisms, plants, and animals [1-3] and have been shown to inhibit "unwanted or foreign" proteolysis and to defend the host tissues against herbivore predation [4, 5]. In plants, PIs are found at very high levels in storage tissues such as tubers and fruits and are argued to serve as defense against herbivores [3, 5]. Recently, Pearce et al. [6] showed that PI accumulation in wild tomato followed a parabolic pattern with age of the fruit; the PI level was low at early (2-3 weeks after anthesis) and late (ripened) stages of fruit growth, but very high at peak fruit growth. They suggested that such a pattern of accumulation may help deter premature dispersal of seeds by dispersers. In this paper, we extend this idea and argue that the dispersal mode of a spedes may strongly influence both the level and the temporal pattern of PI accumulation in its fruit. Analyzing the trypsin inhibitors, a major class of PI in 47 plant species representing various dispersal modes, we offer a test of this hypothesis. Fruits of animal-dispersed compared to those of wind/water or passively (explosively) dispersed species are mostly modified into rich storage organs containing a relatively high level of soluble compounds. A characteristic feature of fruits is the temporal separation of the growth of the mesocarp/pericarp (fleshy part) and the embryo [7]. In most species the embryo initiates growth much later than that of the mesocarp. Such a pattern has important implications for the successful dispersal of fl'uit in animaldispersed species. If dispersers remove fruits when much of the mesocarp growth is complete, but the embryo is still immature (usually coinciding with the peak growth stage of the fruit), plants do not gain any dispersal advantage. Selection in these species should favor the preferential removal of fruits by dispersers at a time when the embryo is mature (usually at the ripened stage of fruit) to gain effective dispersal of their seeds. Accordingly, in species where fruits are dispersed by animals, selection can be expected to favor a high accumulation of PI at the peak growth stage of the fruit (to deter dispersers from removing premature fruits) and low or negligible accumulation at the ripened stage of fruit (to encourage dispersers to remove the fruits). In contrast to fleshy fruits, nonfleshy fruits dispersed passively or by wind, do not run the risk of being removed prematurely by dispersers because, unlike fleshy fruits, their pericarp is not generally modified into rich storage organs. Thus, in these species, selection should not favor the accumulation of PI in fruits. Further, for the same reason, though the temporal pattern of growth of pericarp and embryo in nonfleshy fruit is also separated as in the fleshy fruits, selection should not favor any temporal pattern of PI accumulation in fruits dispersed passively or by wind. Randomly collected fruits of species representing the three dispersal modes, animal, wind/water, and passive (Table 1), available at the Botanical Garden, University of Agricultural Sciences, Bangalore (12 ° 58'N, 77 ° 35'E), were assessed for a major class of PI, namely, trypsin inhibitors (TI). The TI levels were determined in the rues©or pericarp during the peak growth phase of the fruits, when the growth of the fruit tissue was nearly complete. To examine the temporal pattern of TI accumulation for two randomly selected species of each dispersal mode, the TI levels of the fruit tissue were estimated at three stages of growth, namely, immediately following fertilization; at the peak growth stage; and at the ripened stage. Five hundred mg of the fruit tissue (mesocarp or pericarp) from randomly collected fruits of each species was macerated in 2.5 ml of 0.01 M potassium phosphate buffer (pH 7) containing 1 M KC1, and centrifuged at 18000 g for 10 min at 4 °C. The supernatant was depigmented by gel filtering through a Sephadex G-25 column (1 x 10 cm), equilibrated with 0.01 M phosphate buffer containing 0.15 M NaC1 (pH 7.6); 1-ml fractions were eluted with the same buffer. The fractious containing proteins, as detected by the dye-binding method [8], were pooled and analyzed for the presence of trypsin inhibitors. The trypsin inhibitors in the samples were estimated according to [9]. The data were expressed as trypsin inhibitory units (TIU) per gram fresh weight as

The ratio of male to female flowers per inflorescence inAcalypha fruiticosa increases from bottom to top inflorescence of the plant and also along the altitudinal gradient. The increase is due to increase in male flower number per inflorescence. We explain these facultative changes in sex-ratio as fitness optimising strategies of the plant in response to altered success of males from the bottom to the top of the plant and along altitude which is primarily due to changes in pollen donation pattern.

Seed number per pod is negatively skewed in Leucaena leucocephala. Post-fertilisation abortion of pods does not completely explain the skewed distribution. It is shown that a pre-fertilisation regulation effectively restricts the formation of pods with less than a certain number of seeds. The regulation is rendered through the inhibition of pollen grain germination by the stigmatic fluid when the pollen grain is less than a certain critical load in the stigma. Such a control is shown to have implications in the evolution of pollen package units, generation of male gametophytic competition and the economy of packing seeds in pods.

The paper traces shifts in the reproductive behaviour as influenced by the selective pressures of crop domestication, in the genus Eleusine, from the wild species. E. africana to its domesticated form E. coracana. Among other changes we consider temporal features of flowering, nature of anthesis and dehiscence, the stigma to lemma length ratio determining the extent of stigma protrusion and the pollen grain to ovule ratio as important in changing the breeding behaviours. These changes are viewed as evolutionary responses of plants to their respective ecological niches.

Dalbergia sissoo, a wind-dispersed tropical tree, shows a positively skewed distribution of seeds per pod. This is attributed to the enhanced dispersal advantage of few-seeded pods due to their reduced wing loading (ratio of weight to pod surface area) and low settling velocity. The proximate mechanisms causing the positively skewed distribution were investigated. The distribution could not be attributed to the distribution pattern of ovule number per ovary, pollen grain limitation, lack of ovule fertilization, or post-fertilization elimination of many-seeded pods. Rather, it was caused by the post-fertilization abortion of seeds within a pod 2 weeks after fertilization. This intra-pod seed abortion (IPSA) is due to a dominance hierarchy of fertilized ovules from the distal (near stigma) to the basal end, generated by the temporal differences in fertilization. The dominant developing seeds at the distal end cause the abortion of others through the production and diffusion of an aborting agent. When the dominance hierarchy of the siblings is not intense, pods are formed with more than one seed. We argue that the positively skewed distribution of seeds per pod is not due to maternal regulation but is a result of sibling rivalry. We propose that this sibling rivalry is generated by genetic differences in pollen grain fitness and disucss the results in the context of parent-offspring conflict.

The female flowers of Croton bonplandianum bear nectar glands which become active during fruit maturation and attain peak activity just prior to the splitting of fruits. This temporal specificity of nectar gland activity is shown to facilitate seed dispersal by ants, which are attracted to the plant only during the fruit maturation period. The nectar glands establish a "nectar influence zone" with a radius of 60 cm around the plant within which seed dispersal by ants is effective. Seed dispersal by ants is facilitated only if the seeds are placed within this nectar influence zone. This is accomplished by an intriguing evolutionary shift in the maturation pattern of the fruits. Unlike the usual acropetal development, fruit maturation in Croton is temporally asymmetrical, with the fruits nearer the parental axis maturing early. This unique pattern of fruit development together with the polychasial branching system leads to a concentration of seeds within the nectar influence zone and enhances seed dispersal by ants. The proximate factors responsible for this asynchronous fruit maturity were investigated.