S. 1996. Proteolylic activity in the maize pollen wali, -Physiol. Plant, 98: i72-17S, A new protease from maize {Zea may.'; L,) pollen is described. It was purified using gel filtration, ion exchange and high performance liquid ehromatography, SDS-PAGE and HPLC showed that the enzyme ha,s a dimeric stracture of M, ca 60 000, Inhibitor investigations indicated an aspartic acid residue in it,s active site. The optimum pH for maize pollen aspartic proteinase activity was 5,6, and the optimum temperature was 45°C, The enzyme is easily eluted from the pollen grains and, as confimied by enzymoblotting after isoelectric focusing, it is located in the pollen wall. Similar to metallo-proteinases, its activity is inhibited by Zn'*, The pi value for purified aspartic proteinase, as estimated after IEF, was 5,0, Two-dimensional electrophoresis analysis of proteins eluted from maize pistils suggests that the enzyme digests the proteins and may be involved in pollen-tuix germination. The properties of serine and aspartic proteinases from maize pollen are compared.

A new protease from maize (Zea mays L.) pollen is described. It was purified using gel filtration, ion exchange and high performance liquid chromatography. SDS‐PAGE and HPLC showed that the enzyme has a dimeric structure of M, ca 60,000. Inhibitor investigations indicated an aspartic acid residue in its active site. The optimum pH for maize pollen aspartic proteinase activity was 5.6, and the optimum temperature was 45°C. The enzyme is easily eluted from the pollen grains and, as confirmed by enzymoblotting after isoelectric focusing, it is located in the pollen wall. Similar to metallo‐proteinases, its activity is inhibited by Zn2+. The pL value for purified aspartic proteinase, as estimated after IEF, was 5.0. Two‐dimensional electrophoresis analysis of proteins eluted from maize pistils suggests that the enzyme digests the proteins and may be involved in pollen‐tube germination. The properties of serine and aspartic proteinases from maize pollen are compared.

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Anatomical investigations of the stem in seven Zea mays L. Inbred lines were performed on specimens bred in the Experimental Institute of Breeding and Plant Acclimatization in Smolice. Two of the lines (bm1 and bm2) including the gene brown midrib were characterized by a higher digestability. The remaining five lines (S215, S335, 5336, S336A and S339) were selective inbred lines used as components in hybrid breeding at the Institute in Smolice. The investigated lines were compared in respect to 50 anatomical traits of the stem. The comparisons were performed by means of the Wrocław dendrite method. The lines formed three distinct groups according to the degree of similarity. The first group consisted of two lines with the gene brown midrib (bm1 and bm2), the second of four lines (5215, S336, S336A and S339), and the third of line S335. The inclusion of both the lines with gene bm into one group was based on similarity regarding the set of traits of parenchyma, particularly of the peripheral part of the stem, as well as metaxylem and metaphloem traits. However, these lines differed considerably in respect to epidermis traits. It was peculiar that the stomata of the Amaryllis type occurred in one of the lines (S339). Each line made a specific mosaic of traits. The sets of traits characterizing the particular lines were specific in such a degree that they could be used, like a fingerprint, for their identification

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