Peanut root and root nodule responses to drought at several ages of plant

anglais. Some experiments of water stress on peanut yield have been done, but there is a lack of information concerning the water stress effects on root growth and root nodule. A pot experimet was done with completely randomized design with 4 replications. The treatments were drought imposed at several periods of age of plants, with the length of each period was 4 weeks. Observations were done for plant and soil water status, root growth, root dry matter and number of root nodules. Results of the experiment showed that soil water potential and relative water content of plant reduced under drought condition. Length of drought period, wet period occurred previously did not affect soil and water status of drought stressed plants. Drought condition increased root growth and root dry weight of peanut, but volume and length of main root were not affected. Root dry weight was not affected by the age of plant when the drought accurred, but plant stressed for 8 weeks or more had root dry weight heavier then those stressed for 4 weeks. Drought reduced the number of root nodules, especially when it occured during the fastest growth from 6 up to 12 weeks after planting. The longer the drought occurred the lower the number of root nodules produced

indonésien. Penelitian tentang pengaruh kekeringan terhadap hasil biji kacang tanah telah banyak dilakukan namun masih sangat sedikit yang memperhatikan pengaruhnya terhadap perakaran. Suatu penelitian pot telah dilakukan dengan rancangan acak lengkap dengan 4 ulangan. Perlakuan kekeringan diberikan pada beberapa periode umur tanaman dengan lama perlakuan masing-masing sepanjang 4 minggu. Pengamatan dilakukan terhadap status lengas tanah dan tanaman, pertumbuhan akar dan bobot kering akar. Hasil penelitian menunjukkan potensial air tanah dan kandungan air nisbi tanaman menurun saat terjadi kekeringan. Panjang periode kekeringan dan periode basah sebelum kekeringan tidak mempengaruhi status air tanah tanaman pada tanaman yang mengalami kekeringan. Keadaan kering meningkatkan pertumbuhan akar dan bobot kering akar kacang tanah, namun volume dan panjang akar utama tidak terpengaruh. Bobot kering akar tidak terpengaruh oleh umur tanaman saat terjadinya kekeringan, namun tanaman yang mengalami kekeringan 8 minggu atau lebih mempunyai bobot kering akar yang lebih berat dibanding yang mengalami selama 4 minggu. Kekeringan menurunkan jumlah bintil akar, terutama bila terjadi pada saat pertumbuhan maksimum dari 6 sampai 12 minggu sesudah tanam. Semakin lama kekeringan terjadi semakin sedikit jumlah bintil akar terbentuk