Tamarind monograph.pdf - Crops for the Future

light yellow in colour, have been reported to contain high nitrogenase
activity (Quiniones, 1983). Rhizobial isolates from the Philippines have been
described as gram negative, with short and long rods (Quiniones, 1983). In
the semi-arid region of Nigeria, tamarind has been recognised as a potential
nitrogen fixing tree (Okoro et al., 1986).
In Thailand, Towprayoon et al. (1996) and Chiemsombat et al. (1996)
reported negative results following inoculation with Rhizobium as there was
no indication of nodule formation or the association of the Rhizobium with
the tamarind roots. Also in Pakistan, Qadri and Zehra, (2004) reported that
the roots of tamarind do not develop nodule-like structures and have no
bacteria or Rhizobium association commonly observed in other leguminous
plants. The acetylene reduction assay for nitrogen-fixing activity was unable
to demonstrate any symbiotic nitrogen fixation in tamarind roots and
nitrogen-fixing bacteria were absent in the roots. The most outstanding
feature noted in the roots were finger-like projections called ‘microvilli,’
whose function is unknown, but it has been suggested that they assist in
water absorption. Detailed information on the root structure of tamarind is
limited.
Yoneyama et al. (1993) studied the natural abundance of 15 N (delta 15 N)
in leaves harvested from tropical legumes in Brazil and Thailand. The 15 N
values were lower in Sesbania grandiflora, Leucaena leucocephala and
Casuarina species pointing to a major contribution from N-fixation, while
those of tamarind had high delta 15 N values. Many of the above studies
have proved inconclusive. The ability of tamarind to fix atmospheric N
deserves further investigation. If specific rhizobia could be identified, they
could be used to enhance nitrogen nutrition and thus increase the growth rate
of this species.
Ilango et al. (2000) carried out a series of experiments to test the effects of
microbial nodulants, Rhizobium ALM2, 108cells/g and Pseudomodules
striata PBZ, 109 cells/g on growth, biomass production and nutrient uptake
in tamarind at the nursery stage. The combined preparation clearly increased
root and shoot length and total leaf area compared to no modulation. There
was thought to be a symbiosis between the micro-organisms that helped the
availability and uptake of nutrients.
5.4.3.3 Mycorrhizal associations
Tamarind seedlings inoculated with 13 arbuscular mycorrhizal fungi (AMF)
from various sources around the world have been demonstrated to exhibit
increased leaf number, plant height, stem girth, biomass, phosphate and zinc
content. The number of VAM spores in the soil, percentage root colonisation
and external hyphae measured by soil aggregation were also higher.
Tamarind responded best to inoculation with Gigaspora margarita, Glomus
fasciculatum and Pisolithus tinctorius (Reena and Bagyaraj, 1990; Trate and
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