Rhizosphere Microorganisms and Their Effect on Fruit Quality - Postharvest Biology and Technology of Fruits, Vegetables, and Flowers - page 368

effects of AMF on fruit may be provided through enhanced phosphorus uptake among other
factors, in our experiments the positive impact of AMF on fruit is present even at low P level
fertilization; therefore, the role of P uptake in enhancing quality of fruits in mycorrhizal
plants is not clear.

17.4.4 Secondary metabolite production

Interestingly, it has been shown that the production of essential oils could be influenced by
AMF inoculation as well. Kapoor et al. (2002) suggested that the utilization of AMF may im-
prove the quantitative and qualitative yield of essential oil in coriander ( Coriandrumsativum
L.) fruits. Fruits of plants inoculated with Glomus macrocarpum or Glomus fasciculatum
contained more essential oil (28 and 43%, respectively) than those of noninoculated plants.
Moreover, gas chromatography of essential oil showed increased concentration of geraniol
and linalool in plants inoculated with G. macrocarpum or G. fasciculatum , respectively.
From the commercial point of view and due to the growing interest in the bioactive com-
ponents, pigment content should be taken into account for evaluating the effect of AMF on
product quality. Mena-Violante et al. (2006) found that plant inoculation with AMF con-
sortia decreased chlorophyll concentration and increased carotenoids concentration in fruit
of Capsicum annuum . Additionally, concentration of pigment was significantly influenced
by the AMF inocula under drought. Thus, carotenoid concentration increased in fruits of
plants inoculated either with G. fasciculatum or AMF consortium when compared to non-
inoculated plants not exposed to drought. Mena-Violante et al. (2006) suggested that the
color changes found in fruits of C. annuum inoculated with AMF could be related to the
ripening process due to the alterations in chlorophyll and carotenoid accumulation patterns.
However, more work must be done to substantiate these results. It is worthy to point out that
under drought, fruits in plants inoculated with G. fasciculatum reached the same C* values
and chlorophyll concentrations of those in noninoculated plants not subjected to drought.
Color attributes of tomato fruits from plants subjected to AMF inoculation are given in
Table 17.4 (Mena-Violante et al., 2003).

17.4.5 Ripening

Fruit ripening is a highly complex process, characterized by a series of coordinated bio-
chemical and physiological changes that lead to the development of a soft, edible fruit.

Table 17.4 Effect of the arbuscular mycorrhizal fungus
G. fasciculatum on fruit color of tomato ( L. esculentum Mill. cv.
Rıo Fuego) at the red stage

L ∗ A ∗ Treatments Phosphate (mg/L)

Noninoculated plants 22 21.0c 1.28c

44 21.6c 2.18b

G. fasciculatum -inoculated 22 23.7a 5.66a

plants 44 22.3b 2.36b

L ∗

indicates lightness from white = 100 to black = 0.

A ∗

− +

60).
Means followed by different letter within each column are signifi-
cantly different based on MSD test ( p

is the red-green axis (from 60 to

< 0 . 05, n = 10).