Four species of different successional status (Albizia falcataria = Paraserianthes falcotaria, Alstonia macrophylla, Michelia champaca and Swietenia macrophylla) were surveyed to construct spacing ...and thinning guidelines for their establishment in plantations in central and southwest Sri Lanka. The species selected are commonly planted as shade trees in Kandy district and all have desirable timber properties. Tree measurements taken were diameter at breast height and crown width. These parameters were sampled on trees located in stands of different density. Sixty individuals were selected that represented all size classes and stand densities for each species. Data of diameter breast height and crown width were used to construct spacing and thinning guidelines that were compared among species. Results showed that each species uses growing space differently under contrasting size classes. Guidelines based on these relationships are appropriate for species that are being introduced into new plantation systems where spacing and thinning information from permanent plots is not available. Maximum crown width can also be used to evaluate appropriate plant spacing of successionally compatible mixtures of tree species in a plantation. Empat spesies daripada status sesaran (Albizia falcataria = Paraserianthes falcataria, Alstonia macrophylla, Michelia champaca dan Swietenia macrophylla) telah dikaji untuk menyediakan panduan-panduan penjarakan dan penjarangan bagi penubuhannya di ladang-ladang di bahagian tengah dan barat daya Sri Lanka. Spesies yang dipilih biasanya ditanam sebagai pokok-pokok naungan di daerah Kandy dan kesemuanya mempunyai ciri-ciri kayu yang diingini. Ukuran pokok yang diambil adalah diameter aras dada dan kelebaran silara. Parameter-parameter ini telah dibuat pensampelan pada pokok-pokok yang ditempatkan di dirian-dirian yang mempunyai ketumpatan yang berbeza. Enam puluh pokok yang dipilih mewakili semua kelas-kelas saiz dan ketumpatan dirian bagi setiap spesies. Data diameter aras dada dan kelebaran silara telah digunakan untuk menyediakan panduan-panduan penjarakan dan penjarangan yang dibuat perbandingan di antara spesies-spesies. Hasilnya menunjukkan bahawa setiap spesies menggunakan ruang yang berbeza untuk membesar dibawah kelas-kelas saizyangkontras. Panduan-panduanberasaskanperkaitan ini adalah sesuai bagi spesies yang diperkenalkan untuk sistem-sistem perladangan baru di manamaklumat-maklumatmengenai penjarangan daripada plot kekal tidak diperolehi. Kelebaran maksimum silarajugadapatdigunakan untuk menilai penjarakan penanaman yang sesuai bagi spesie pokok yang mempunyai gabungan yang serasi di sebuah ladang.
Two chloramphenicol resistance mutations out of 123 tested in Aspergillus nidulans are inherited extranuclearly as judged by transmissibility in heterokaryons, lack of segregation at meiosis, and ...independent segregation from all of the eight nuclear linkage groups. They do not recombine with each other. However, experiments in collaboration with G. Turner and R.T. Rowlands show that they do recombine with cytoplasmic mutations to oligomycin resistance (Rowlands and Turner, 1973) and cold-sensitivity (Waldron and Roberts, 1973). These cytoplasmic chloramphenicol resistance mutations are stable and do not affect growth or morphology on antibiotic-free media. Nuclear mutations to chloramphenicol resistance map at a minimum of three loci. At one of these loci, most, but not all, mutations lead pleiotropically to cycloheximide hypersensitivity, and most of these, but not all, also confer pleiotropic hypersensitivity to salicylhydroxamic acid.
Partially dominant mutations to carboxin resistance occur in three, freely recombining, nuclear genes in Aspergillus nidulans. Mutations at all three loci reduce carboxin inhibition of succinate ...dehydrogenase (EC 1.3.99.1), succinate-cytochrome c reductase (EC 1.3.99.1) and succinate oxidase (EC 1.3.99.1) in mitochondrial preparations. It is therefore probable that the ability of carboxin to prevent growth of A. nidulans is a direct consequence of its ability to prevent succinate oxidation.
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