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Ecological Manipulation of Psidium guajava to Facilitate Secondary Forest Succession in Tropical Forests

100%

Otuoma J. , Nyongesah J. M. , Owino J. , Onyango A. A. , Okello V. S.

Journal of Ecological Engineering

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2020

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tom Vol. 21, nr 7

210--221

EN

Psidium guajava L. has been documented as an exotic invasive species in many parts of the world, but little is known about its interactions with native woody species during secondary forest succession in tropical forests. Its invasion and interactions with native species in different stages of secondary forest succession were assessed in Kakamega Rainforest in western Kenya. The study covered three forest blocks each with five different forest types, namely: open fields, young secondary forest, middle-aged secondary forest, old-growth secondary forest and disturbed primary forest, which served as the control. Open fields that were subjected to frequent clearing to control the spread of Psidium guajava remained under a thicket of the species two decades later. On the other hand, open fields where Psidium guajava was ignored, either due to lack of resources or sheer neglect, transformed into young secondary forest stands within a decade. The transformation increased woody species richness from 2.0±0.0 to 5.0±0.0 ha-1, and the Shannon diversity index from 0.30±0.33 to 1.10±0.01. It reduced the dominance of Psidium guajava from 80.5±22.7 to 62.26±0.84% and changed the canopy structure. The change in canopy structure led to the mortality of Psidium guajava stems in the sub-canopy and understory layer, which significantly reduced its stem density from 1,111±313 to 639.4±45 stems ha-1. The pattern was repeated in middle-aged secondary forest stands with woody species richness increasing to 26.0±8.2 ha-1, and Shannon index to 2.72±0.32. Psidium guajava’s dominance and stem density decreased further to 30.44% and 400.57 stems ha-1, respectively, due to mortality attributed to shading by native tree species. In the old-growth secondary forest, only snags of Psidium guajava were recorded. The species was not represented in the disturbed primary forest. The results indicate that Psidium guajava facilitates secondary forest succession by allowing shade-tolerant native tree species to recruit and grow in its shade. It is thereafter eliminated when the native species close the forest canopy. The species can be ecologically manipulated to facilitate post-disturbance forest regrowth and thereafter removing it when the forest canopy begins to close.

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Efficacy of coupling gamma irradiation with calcium chloride and lemongrass oil in maintaining guava fruit quality and inhibiting fungal growth during cold storage

63%

Hassanein R. A. , Salem E. A. , Zahran A. A.

Folia Horticulturae

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2018

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tom 30

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nr 1

3

Effect of pruning Intensities on the performance of fruit plants under mid-hill condition of Eastern Himalayas: case study on Guava

63%

Bhagawati R. , Bhagawati K. , Choudhary V. K. , Rajkowa D. J. , Sharma R.

International Letters of Natural Sciences

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2015

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tom 46

EN

Current study was undertaken to highlight the effect of pruning on improving vigor of old orchards and increasing performance in terms of fruit yield and quality under water and nutrient stressed condition of mid hills of Eastern Himalaya. Guava was taken for the case study and all the physical and chemical properties of the fruits and other attributes of plant were evaluated using standard methods under three pruning intensities (light, moderate and severe) and no pruning. The emergence of bud was earliest in severe pruning, number of buds per shoot was highest with light pruning and cumulative lengths of new shoots were found to be highest in severe pruning. Fruit yield, size and weight were found to increase with pruning intensities and lowest in case of no pruning. Regarding chemical properties, total soluble solids and total sugar found to increase with enhanced pruning severity and least in case of no pruning. Acidity was found to be highest with no pruning and decrease with increase in pruning intensities. Overall pruning found to have rejuvenating impact on aged trees due to better light interception leading to better photosynthetic rate, better nutrient and water supply with reduced canopy and better quality yields.

4

Physical and biochemical properties of selected tropical fruits

63%

Athmaselvi K. A. , Jenney P. , Pavithra C. , Roy I.

International Agrophysics

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2014

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tom 28

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nr 3

EN

This study was conducted to determine the phy- sical and biochemical properties of guava, sapota, and papaya. The physical properties studied were: dimensions, shell ratio, surface area, bulk and true density, porosity, sphericity, packing coeffi- cient, aspect ratio, and roundness index. The specific heat at various mass fractions, biochemical properties like pH, titratable acidity, total soluble solids, and colour analysis were studied for fruit pulps. The viscosity of fruits was studied at various mass fractions. The high sphericity of guava and sapota indicated that those fruits had high rolling capability, which is an important factor for designing hoppers. Bioch emical analysis showed that sapota was the sweetest fruit amongst the three studied.

5

Compositional and enzymatic changes in guava [Psidium guajava L.] fruits during ripening

63%

Jain N. , Dhawan K. , Malhotra S. P. , Siddiqui S. , Singh R.

Acta Physiologiae Plantarum

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2001

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tom 23

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nr 3

6

Water salinity and initial development of four guava [Psidium guajava L.] cultivars in North-Eastern Brazil

63%

Cavalcante I. H. L. , Cavalcante L. F. , Hu Y. , Beckmann-Cavalcante M. Z.

Journal of Fruit and Ornamental Plant Research

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2007

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tom 15

7

Shoot multiplication and plant regeneration of guava [Psidium guajava L.] from nodal explants on in vitro raised plantlets

51%

Rai M. K. , Jaiswal V. S. , Jaiswal U.

Journal of Fruit and Ornamental Plant Research

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2009

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tom 17

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nr 1

29-38

EN

A micropropagation method is described for guava (Psidium guajava L.) using nodal expiants from somatic embryo-derived young and aseptic plantlets. Multiple shoots were induced from axillary buds on MS medium containing different concentrations of N6-benzylaminopurine (BAP), either alone or in combination with kinetin (Kn), indole-3-acetic acid (1AA) or a-naphthalene acetic acid (NAA). Medium containing 1 mg l-1 BAP was the most effective for shoot multiplication. In vitro regenerated shoots developed roots either on MS medium alone or on MS medium supplemented with indole-3-butyric acid (1BA). The rooted plantlets were successfully acclimatized.

PL

Opisano metodę mikrorozmnażania guajawy (Psidium guajava L.) używając eksplantatów węzłowych z młodych i aseptycznych roślin otrzymanych na drodze somatycznej embriogenezy. Wiele pędów było inokulowanych z pachwinowych pąków na po żywce MS zawierającej różne stężenia benzyloaminopuryny (BAP), zastosowanej pojedynczo lub w kombinacji z kinetyną (Kn), kwasem indolilooctowym (IAA) albo kwasem a-naftalenooctowym (NAA). Pożywka zawierająca BAP w stężeniu 1 mg l-1 była najbardziej efektywna. Ze zregenerowanych pędów in vitro rozwijały się korzenie zarówno na pożywce MS, jak i na pożywce MS uzupełnionej kwasem indolilomasłowym (IBA). Ukorzenione ro śliny były pomyślnie aklimatyzowane.

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Response of guava trees (Psidium guajava) to soil applications of mineral and organic fertilisers and biofertilisers under conditions of low fertile soil

51%

Shukla S. K. , Adak T. , Singha A. , Kumar K. , Singh V. K. , Singh A.

Journal of Horticultural Research

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2014

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tom 22

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nr 2