Fruit Tree Physiology

No Abstract

Correlation of Leaf Parameters with Incidence of Papaya Ring Spot Virus in Cultivated Papaya and its Wild Relatives

Papaya ring spot virus (PRSV) disease has been the major impediment in papaya cultivation. The disease is transmitted through three aphid vectors and field tolerance towards this disease varies among Carica papaya cultivars as well as within the Vasconcellea genus. Leaf morphological traits are known to have influence on the probing preferences of aphids. Hence, this study was conducted to know whether the leaf parameters could contribute to the incidence of PRSV possibly by influencing the probing or feeding behaviour of aphid vectors. Leaf parameters viz., leaf thickness, leaf epicuticular wax content, presence and type of trichomes, trichome density were correlated with disease incidence at field conditions. The result revealed that leaf thickness along with epicuticular wax content had significant negative correlation with disease incidence. Similarly, trichome density had negative impact on disease incidence at 99.92% significance level. High epicuticular wax content and high trichome density in V. cauliflora and V. cundinamarcensis were found to be negatively associated with low to very low infection indicating that these parameters may have limited the vector transmission significantly

Metabolite profiling in Mango (Mangifera indica L.) pollen grains in relation to viability

Mango productivity is affected mainly by irregular flowering, proportion of bisexual flowers, poor pollination and fertilization and fruit drop. Poor fruit set in some of the varieties may be associated with the lower pollen viability. The present experiment was initiated to assess the viability of pollen grains and their metabolites in three mango cultivars Amrapali, Alphonso and Totapuri which are differing in their fruit set intensity. The profiling of sugars, amino acids and some of the phytohormones were analysed using Liquid Chromatography-Mass Spectrometry (LC-MS/MS). Assessment of pollen grains in three mango cultivars indicated that free sugars such as fructose and glucose, and available amino acids including serine, proline, lysine, phenylalanine, alanine and glutamic acid were predominantly higher in all the cultivars. Phytohormones like IAA, IBA, ABA, GA,zeatin, jasmonic acid and salicylic acid were significantly different in low fruit setting cultivars Alphonso and Totapuri compared to high fruit setting cultivar Amrapali. In cv. Alphonso all the metabolites were higher at anthesis but later decreased drastically compared to cvs. Totapuri and Amrapali. Pollen viability percentage was significantly higher in cv. Amrapali than in cvs. Totapuri, Alphonso. Among all the cultivars, Amrapali maintained better chemical composition at anthesis and also at two hours after anthesis compared to cvs. Totapuri and Alphonso

Determining Composition of Volatiles in Couroupita guianensis Aubl. Through Headspace-Solid Phase Micro-Extraction (HS-SPME)

Composition of volatile components in Couroupita guianensis Aubl. flowers was analyzed using headspace-solid phase micro-extraction (HS-SPME), followed by capillary gas chromatography and mass spectrometry (GC-MS) separation and identification. In all, 75 compounds were identified accounting for 96.32% of the total volatiles present. The major groups of compounds present were oxygenated terpenoids (35.66%), alcohols (26.92%), esters (17.36%), mono-and sesqui-terpenoids (8.64%), aldehydes and ketones (4.71%), hydrocarbons (1.68%), phenols (0.18%), acids (0.754%) and heterocyclic compounds (0.42%) constituted a small proportion of the volatile profile. The most abundant individual constituent was eugenol (18.95%) followed by nerol (13.49%), (E,E) farnesol (12.88%), (E,E)-farnesyl acetate (6.68%), trans ocimene (6.02%), nootkatone (4.64%), geraniol (2.94%), 2-isopropenyl-5- methyl-4-hexenyl acetate (2.69%), cedr-8-en-13-ol (2.58%), (E,Z)-farnesyl acetate (2.40%) and methyl (11E)-11- hexadecenoate (2.041%). Analytical comparison of composition of volatiles in the flowers, obtained by different methods of extraction, viz., solvent extraction, micro-simultaneous extraction and headspace-solid phase microextraction, revealed specific variations in relative concentrations of the constituent chemicals. Linalool was the major chemical (21.5% and 14.9%) in solvent extract and micro-simultaneous extract, respectively, but appeared in negligible quantity (0.16%) in head-space analysis

Morpho-biochemical characterization of Psidium species

Several Psidium species are available with many important traits, lack of intensive characterization limits their use in guava improvement. Therefore, the present study was carried out to characterize five wild Psidium species (P. molle, P. chinensis, P. guineense, P. cattleianum var. cattleianum and P. cattleianum var. lucidum) and two P. guajava genotypes (cv. ‘Arka Poorna’ and ‘H 12-5’), based on morphological and biochemical traits. Among morphological traits, fruit weight was ranged from 5.22 g (P. cattleianum var. cattleianum) to 225.14 g (‘H 12-5’), however, among biochemical traits, highest TSS (12.06 ºBrix) and total sugars (9.98%) were recorded in cv. ‘Arka Poorna’, while, lowest recorded in P. cattleianum var. lucidum. Highest ascorbic acid was recorded in P. chinensis (205.33 mg/100 g), whereas, lowest recorded in P. guineense (60.83 mg/100 g). A positive correlation was observed among wild Psidium species but none had correlation with P. guajava genotypes for quantitative traits

Comparison of leaf volatile aroma constituents and phenolic acid profiles of the seedling originated polyembryonic mango (Mangifera indica L.) genotypes

In mango, leaf and fruit volatile aroma profiles are variety specific which can be used as fingerprint of a variety. Such biochemical markers can also discriminate the nucellar and zygotic seedlings in polyembryonic mango varieties. In order to validate the applicability of volatile as well as phenolic acid profiles as biomarkers, the open pollinated seedlings of three polyembryonic varieties of mango were compared with their mother trees. Leaf volatile and phenol acid profiling were done using Gas Chromatography/Mass Spectrometry (GCMS) and Liquid Chromatography/Mass Spectrometry (LCMS) methods respectively. The sesquiterpene hydrocarbons were the most abundant in all the genotypes studied. Monoterpenoids were the major compounds in cultivars Vellaikolumban and Olour, while the sesquiterpenoids were the major compounds in cv. Turpentine. While terpinolene was the major monoterpenoid compound in Vellaikolumban and limonene in cv. Olour, the sesquiterpene á-gurjunene was the major compound in cv. Turpentine. Volatile profiling showed clear differences between the varieties but was similar within a variety. Among the 15 phenolic acids quantified in the leaves, P-coumaric acid, gallic acid, and ferulic acids were predominant whereas, vanillic acid, syringic acid, gentisic acid, benzoic acid, and sinapic acids were low in quantity. Phenolic acid profile did not show significant diversity among the varieties and therefore cannot be used for identification of varieties. The volatile profiling can be used for the identification and differentiation of polyembryonic mango genotypes

Seasonal influence on volatile aroma constituents of two banana cultivars (Grand Naine and Nendran) under Kerala conditions

Banana is a tropical fruit with a pleasant flavour, widely consumed throughout the world. Volatile aroma compounds are responsible for olfactory flavor of banana. However, the development of aroma flavors is affected by the atmospheric temperatures during fruit growth period. In order to get good quality fruits in terms of aroma it is essential to understand the optimum temperature for maximum aroma production. The approach used in this study was to alter the dates of harvest to understand the optimum temperature required for maximum production of volatile compounds under Kerala conditions. The results revealed that with increased temperature volatile aroma compounds decreased in cvs. Grand Naine and Nendran. Total volatile compounds were higher in cv. Grand Naine compared to cv. Nendran. Cultivar Nendran recorded increased concentrations of esters, alcohols and decreased aldehydes, ketones, hydrocarbons and acids at high temperatures. Phenols and other constituents did not show much variation with respect to the temperature variation in both the cultivars. Among esters, Isoamyl butanoate and 3-Methylbutyl-3-methylbutyrate esters were the most abundant in both the cultivars. Ketones, especially 4-Methyl-1-penten-3-one was higher in cv. Nendran whereas esters were lower compared to cv. Grand Naine. Total area of aroma constituents in cultivars Grand Naine and Nendran were high in October followed by February with mean atmospheric temperature of 30.5ºC and 32.6ºC respectively. In case of cv. Nendran, total area of esters and alcohols were maximum at high temperature (34.5ºC) but in cv. Grand Naine, esters and alcohols decreased with high temperature. Results indicated that fruits harvested in October were better in terms of volatile aroma quantity in both the cultivars due to lower atmospheric temperature. Seasonal variations affected the two cultivars differentially in terms of percentage of groups of volatile compounds

Fruit/Seed Morphology, Seed Drying and Germination Studies in Baccaurea courtallensis (Muell.) Arg., a Threatened Under-Utilized Fruit Species of Western Ghats in India

A study was under taken on fruit and seed morphology, seed drying, seed germination and storage behavior in Baccaurea courtallensis, as, this plant is propagated mainly through seeds. Its fruit is a berry consisting of an outer, semi-hard but fleshy rind 2-3 mm thick. The cavity inside the rind is normally occupied by a single, arillate seed, but, two seeds are also seen occasionally. Fresh rind was found to be rich in antioxidants, with 237mg total phenols and 93mg flavonoids per 100 gram fresh weight, but was poor in Vitamin C. A thick, fleshy endosperm is surrounded by the inner seed-coat. The endosperm surrounds the embryo consisting of two papery-thin cotyledons and a minute embryonic axis. Germination was highest (96.7%) when seeds were sown immediately after extraction, with moisture content of about 50%. Reduction in moisture to below 34% showed a drastic decrease in germination. Dried seeds took longer to germinate than did the fresh ones. Seeds with 21% moisture recorded about 60% germination whereas, seeds with 10.2% or 8% moisture failed to germinate, indicating a recalcitrant seed. Temperature in the range of 25-30°C was found to be optimum. Of the two media tested for raising the seedlings, cocopeat medium was superior as, it induced faster growth of the seedlings. Seedling root and shoot were considerably longer, with higher seedling survival rate in cocopeat than in the soil-mix medium. Seedling establishment was poor when planted out of their natural habitat

Molecular Mechanisms Involved in Biosynthesis and Regulation of Carotenoids in Plants

Carotenoids are coloured compounds beneficial to plants and humans. Some of the major health benefits carotenoids provide include Vitamin A precursors and, antioxidants besides being involved in several physiological functions. Even though several carotenoids are synthesised by plants, only a few like beta/ alpha carotenes and cryptoxanthin serve as Vitamin A precursors. The rest are useful as antioxidants. To draw maximum benefits from carotenoids, we need to incorporate these in crop improvement programmes for enhancing available Vitamin A precursor carotenoids. Therefore, it is essential to study biosynthesis of carotenoids, their genetics and their control. In this review, we focus on factors regulating carotenoid biosynthesis, metabolism and storage in plastids. Transcriptional and genetic control of carotenoid production in plants is discussed in the review using several mutants too. Further, environmental regulation of carotenoid biosynthesis is also highlighted. Carotenoid-rich fruits and vegetables have greater economic value owing to their health-promoting effects. Besides,carotenoids have several industrial applications. Therefore, knowledge of regulation mechanism in carotenoid production in plants can help develop crop varieties or technologies, thus generating carotene-rich fruits and vegetables

Antioxidant capacity, radical scavenging ability, total phenols and flavonoids in three types of betelvine (Piper betle L.)

Betelvine (Piper betle L.) leaves from female (Bengaluru local), male (Madras type) and meeta paan (sweet type) were analysed for antioxidant capacity (FRAP) and radical scavenging ability (DPPH) using acidic methanol extracts. FRAP and DPPH values were higher in the leaves of Bengaluru local followed by Madras type and were lowest in sweet type of betelvine. However, chlorophyll was higher in female and sweet betelvine when compared to Madras type. Bengaluru local also recorded higher total phenols and flavonoids followed by Madras type and sweet betelvine recorded lowest phenols and flavonoids. Higher antioxidant and radical scavenging capacities of female and male types was mainly due to the higher phenols and flavonoids and not due to total chlorophyll content. The study indicated that the total phenol content of betelvine is comparable with that of tea powder. &nbsp