14. Six glabrous phenotypes of rice classified with a scanning electron microscope

K. kOBAYASHI1, R. ISHIKAWA1, M. SENDA2, S. AKADA2, T. HARADA1 and M. NIIZEKI1

1) Faculty of Agriculture, Hirosaki University, Hirosaki. 036 Japan
2) Gene Research Center, Hirosaki University, Hirosaki, 036 Japan

Rice leaves have two kind of trichomes which consist of micro and macro hairs. Micro hair are located along the stomata cells or besides motor cells, and macro hairs are located on silica cells over a thin vascular bundle. Glabrous1 (gl1) modifies trichomes on leaves and also on glumes (Oka 1953).

We made a new classification of glabrous mutants showing differential morphological modifications of micro and macro hairs, as well as density of these hairs. First, gla-brous phenotypes were screened for glumes and mature leaves. Thirty-six out of 1287 strains were selected with modified phenotypes. One mutant classified as Type 6 had only glabrous leaves but had apiculus hairs on glumes. Other mutants have no apiculus hair on glumes. Type 6 is characterized with low density of wild type hairs or round-edge macro hairs only on mid-rib, but has normal apiculus hair on glumes. Mature leaves were observed with a scanning electron microscope (SEM). Thirty-six mutants examined were classified into in six different phenotypes (Table 1, Fig. 1).

We have not conducted allelism test between these glabrous mutants as yet. However, these qualitative differences suggest that they may have different genes for trichome development. Allelism tests will be carried out.

References

Oka, H.I., 1953. Phylogenetic differentiation of the cultivated rice. 1. Variations in various characters and character combinations among rice varieties. Japan. J. Breed. 3: 33-43.

Hosikawa, K.,1975. Growth of rice. Noubunkyo, Tokyo, pp.90.

Table 1. Six glabrous phenotypes on adaxial side leaves and on glumes

Type
Number of strains
Macro hairs
Micro hairs

Trichome
on
glumes

Wild type
hair
Long hair
Type 1
12
-
-
-
-
Type 2
15
-
-
+
-
Type 3
4
+
-
-
-
Type 4a
1
+
+
-
Type 4b
1
+
+
-
Type 4c
1
+
-
-
Type 5
1
+1)
+1)
+
-
Type 6
1
++2)
-
++
+++
Control
 
+++ 
-
+++
+++
Taichung 65 used as control. - meaning there is no trichomes. +, ++ and +++ meaning rare
density, lower density or nomal density of trichomes.
1) Macro hairs only on mid-rib. 2) Wild type or round edge hairs on leaves.