Malays. Appl. Biol. (December 2000) 29(1&2): 1-8
EFFECTS OF PRE-HARVEST PRODUCTION PRACTICES ON POST-HARVEST WATER LOSS OF LEEKS AND PAK CHOI
MAHMUD, T.M.M.1, RAMLAN, M.F.1 and AHMAD, S.H.2
1 Department of Crop Science, 2 Department of Agricultural Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul-Ehsan, Malaysia.
ABSTRACT
The utilization of pre-harvest conditions as crop management tools to control post-harvest weight (water) loss had been studied. Studies on two model crops i.e. leek and pak choi had shown some promising uses of these production conditions in regulating weight loss from harvested leafy vegetable. Pre-harvest conditions such as environmental (temperature and light) and cultural (mineral nutrition, density of planting, salinity and irrigation) had been investigated. Water retention during storage was improved in pseudostems from leeks grown with adequate water supply, high light level, lower temperatures and K supplement in the growing media. Pseudostems from salinized plants conserved more watet than non-salinized plants and leeks grown at 35 plants nr2 retained water better than the other three plant densities (17.5, 22 and 44 plants nr2). There were significant (p<0.001) interactions between temperature, salinity and water stress and cultivars on water loss from shoots of pak choi with shoots produced at 25°C, moderate salinity and water stressed being more resistant to water loss.
ABSTRAK
Kajian terhadap penggunaan keadaan persekitaran sebelum tuai sebagai alat pengurusan tanaman bertujuan untuk mengawal kehilangan berat (air) di peringkat pascatuai telah dijalankan. Kajian terhadap dua jenis sayuran yang dijadikan sebagai model iaitu 'leeks' dan pak choi telah menunjukkan bahawa pengawalan persekitaran pengeluaran tanaman mempunyai potensi untuk digunakan sebagai kaedah bagi mengurangkan kehilangan berat daripada sayuran berdaun setelah dituai. Keadaan persekitaran dan kultur yang berbeza seperti suhu, cahaya, pemakanan mineral, kepadatan tanaman, kemasinan dan pengairan telah dikaji. Ketahanan daripada kehilangan air semasa penyimpanan batang palsu leeks dapat diperbaiki dengan penanaman dengan pengairan yang mengcukupi, paras cahaya yang tinggi, suhu yang rendah dan tambahan kadar K di dalam media tanaman. Batang palsu yang dihasilkan di dalam keadaan kemasinan berupaya untuk mengekalkan kandungan air yang tinggi berbanding dengan tanaman yang dihasilkan tidak dalam keadaan kemasinan. Kepadatan 35 pokok nr2 memberikan hasil yang lebih berupaya untuk mengekalkan kandungannya berbanding dengan kepadatan-kepadatan lain (17.5, 22 dan 44 pokok m-2). Terdapat interaksi yang ketara (p<0.001) antara suhu, kemasinan dan ketegasan air dengan kultivar bagi pucuk pak choi yang dihasilkan dalam suhu 25 °C, kemasinan dan ketegasan air sederhana. Rawatan-rawatan ini di dapati menghasilkan pucuk yang lebih tahan kepada kehilangan air.
Key words: post-harvest, pre-harvest, water loss, leeks and pak choi.
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