Info

(1995)

Peter et al. 2002

Peter et al. 2002

aIISR, Unpublished information from author's laboratory. MS, Murashige and Skoog (1962) medium; SH, Schenk and Hildebrandt (1972) medium; WPM, Woody Plant Medium (McCown et al., 1979) medium. IAA: Indole-3-acetic acid

IBA: Indole-3-butyric acid NAA: a-naphlhalene acetic acid 2, 4-D: 2,4-Dichloropenoxy acetic acid BAP: 6-Benzylaminopurine

2,4-D, kinetin, and BAP in different concentrations and combinations (Table 4.1). Only Pillai and Kumar (1982) used SH (Schenk and Hildebrandt, 1972) medium.

Nirmal Babu (1997) tested various explants—vegetative bud, immature inflorescence, leaf (pseudostem), ovary, and anther—for their morphogenetic responses (see Figure 4.1A-L) on MS basal medium supplemented with cytokinins (BAP and kinetin) and auxins (NAA and 2,4-D). MS basal medium supplemented with auxin (NAA 0—4 mgl"1) and cytokinin (BAP 0—4 mgl"1) gave positive response in inducing multiple shoots and roots. The presence of NAA at low concentrations (1 mgl"1) resulted in good growth of culture, root induction, and shoot multiplication and addition of BAP at 4 mgl"1 increased the multiple shoot induction, but reduced root induction. NAA alone at high concentration (2—4 mgl"1) inhibits shoot growth as well as root induction, whereas BAP alone at higher concentration (4 mgl"1) induced only multiple shoots and rarely roots. Earlier workers also reported that BAP and NAA combinations were best for shoot

The Growth Stage Ginger

Figure 4.1 Stages in ginger tissue culture: (a) ginger plant; (b) vegetative bud explant and culture initiation; (c) multiple shoots; (d) regenerating callus; (e) organogenesis and embryogenesis from ovary derived callus; (f) conversion of floral buds into vegetative buds; (g) in vitro fruit formation; (h, i) plant regeneration from anther culture; (j) in vitro rhizome formation; (k, l) stages in hardening.

Figure 4.1 Stages in ginger tissue culture: (a) ginger plant; (b) vegetative bud explant and culture initiation; (c) multiple shoots; (d) regenerating callus; (e) organogenesis and embryogenesis from ovary derived callus; (f) conversion of floral buds into vegetative buds; (g) in vitro fruit formation; (h, i) plant regeneration from anther culture; (j) in vitro rhizome formation; (k, l) stages in hardening.

multiplication in ginger (Sakamura et al., 1986; Charlwood et al., 1988; Sakamura and Suga, 1989).

The induction of both roots and shoots in the same medium reduces the time taken for cloning considerably, and in ginger it takes about 60 days for an explant to develop into a well-developed plantlet in the first cycle using a primary explant from the greenhouse-grown plant. When the subcultures are initiated from the in vitro developed axillary shoots, the rate of proliferation was further increased and the time taken for plantlet development was reduced to 45 days per cycle (Nirmal Babu, 1997).

Vegetative Bud Culture

Vegetative bud explants containing both shoot tip and axillary buds were used for clonal multiplication. Growth regulators, NAA (1 to 4 mgl-1) and BAP (1 to 4 mgl-1) were tested in various combinations. Only 50 percent of the explants could be established, whereas the rest were lost due to contamination. The explants took nearly 20 days for exhibiting first signs of growth and bud break and subsequently produced both multiple shoots as well as roots in all the growth-regulator concentrations tried. The number of shoots ranged from 1 to 9 and the number of roots ranged from 1 to 10 after 60 days of culture (see Figure 4.1a—c). Both NAA and BAP induced multiple shoots and roots in ginger vegetative bud explants. However, the cultures responded differently in different treatments. MS medium supplemented with 4 mgl-1 NAA and 4 mgl-1 BAP gave the lowest response (40 percent) for production of multiple shoots or roots, whereas that supplemented with 1 mgl-1 NAA and 4 mgl-1 BAP or NAA alone (1 mgl-1) gave highest culture response (90 percent). The mean number of multiple shoots ranged from 1.2 to 5.2 in different treatments. MS medium supplemented with 3 mgl-1 each of NAA and BAP gave the lowest number (1.2) of multiple shoots, whereas while that supplemented with 1 mgl-1 NAA and 4 mgl-1 BAP gave the highest number (5.2).

The mean number of roots ranged from 0.7 to 5.4 in different treatments. MS media supplemented with 1 mgl-1 NAA gave the highest number (5.4) of roots and MS media supplemented with 4 mgl-1 BAP gave the least number (0.7) of roots.

Considering that both induction of multiple shoots and roots are equally important, development of both in a single medium reduces the time taken for plant development. In such cases, MS medium with 1 mgl-1 NAA alone or 1 mgl-1 NAA and 4 mgl-1 BAP was ideal for multiplication of ginger from vegetative bud explants (see Table 4.1). These treatments were significantly superior to the rest with respect to multiple shoot production and root induction. The plantlets from the vegetative bud cultures are healthy, robust, and 8 to 12 cm tall with three to four roots. These plantlets were hardened in a humid chamber for 20 to 25 days with 85 percent establishment.

Inflorescence Culture and Development of Shoots from Floral Meristem

Floral meristems from young inflorescences, when the determination of an individual floral meristem was not canalized, can be induced to grow vegetative shoots in vitro. In rhizomatous crops like ginger, the use of floral meristems reduces the problem of culture contamination that is so common when rhizome explants are used.

In ginger, vegetative shoots were produced in 70 percent of the explants when 1-week-old inflorescences were cultured on MS medium supplemented with 10 mgl-1 BAP and 0.2 mgl-1 2,4-D. One or rarely two plantlets developed per axil of the bract in the majority of the cases (see Figure 4.1f). In about 26 percent of the cultures multiple shoots ranging from 5 to 25 were induced. These shoots grew into complete plantlets in 7 to 8 weeks' time. However, in 20 percent of the cultures the older flower buds

Table 4.2 Morphogenetic response of immature inflorescence explants on MS basal medium

Was this article helpful?

0 0
Essential Aromatherapy

Essential Aromatherapy

Have you always wanted to know what is aromatherapy? Here are some invaluable information on aromatherapy. I leave absolutely nothing out! Everything that I learned in order to improve my life with aromatherapy I share with you.

Get My Free Ebook


Post a comment