Abstract

The expansion of sugarcane areas as a support to national sugar production has shifted to sub-optimal dry land. In drought stress conditions, early growth of sugarcane usually can inhibite and decrease its productivity. This study aimed to test the efficacy of organic biostimulant in increasing vegetative growth of sugarcane in the dry land. Firstly, seedlings were submerged with biostimulant of Citorin-Rfor overnight. Secondly, the biostimulant application of Citorin-S was carried out by foliar sprayat age1 and4 months old trees. Humicacid 0.5% (v/v) was applied in soil before planting while the application of mycorrhiza was carried out by direct pouring on soil during planting. The results showed that the initial vegetative growth of biostimulant-treated sugarcane stem diameter and length were 23% wider and 27% higher compared to that of control, respectively. In subsequent growth cycle, all observed vegetative parameters showed higher growth value in the biostimulant-treated sugarcanes than that of the control. Plant height, stem diameter and number of tillers of biostimulant-treated sugarcanes had significantly higher values than that of the control. P3 treatment (organic biostimulant plus humic acid and mycorrhiza) was the best treatment. The height and diameter of P3 sugarcane stems were 47% wider and 59% higher, respectively, compared to that of control at 107 DAP.[Keywords: biostimulant, plant height, stem diameter, number of tillers, number of leaves] Abstrak Penambahan areal tanaman tebu untuk mendukung peningkatan produksi gula nasional telah bergeser ke areal sub-optimal lahan kering. Pada kondisi cekaman kekeringan, pertumbuhan awal tebu biasanya terhambat dan dapat menurunkan produktivitas saat panen. Penelitian ini bertujuan menguji efikasi biostimulan organik untukmeningkatkan pertumbuhan vegetatif tanaman tebu pada fase awal di lahan kering. Perlakuan biostimulan Citorin-R diaplikasikan pada benih dengan cara perendaman semalam. Perlakuan kedua, biostimulan Citorin-S disemprotkanpada saat tanaman tebu berumur 1 dan 4 bulan secara foliar spray. Aplikasi asam humat 0,5 % (v/v) di tanah dilakukan sebelum tanam, sedangkan aplikasi mikoriza dilakukan dengan pemberian langsung pada tanah saat penanaman bagal tebu. Hasil penelitian menunjukkan bahwa nilai pertumbuhan vegetatif awal tanaman tebu perlakuan memiliki diameter batang sekitar 23% dan tinggi tanaman 27% lebih tinggi daripada tebu kontrol. Pada pertumbuhan selanjutnya, semua parameter vegetatif yang diamati menunjukkan nilai pertumbuhan yang lebih tinggi pada tanaman tebu perlakuan daripada kontrol. Tinggi tanaman, diameter batang dan jumlah anakan secara statistik berbeda nyata lebih tinggi pada tanaman tebu perlakuan daripada kontrol. Perlakuan P3 (biostimulan organik plus asam humat dan mikoriza) adalah perlakuan terbaik. Tinggi dan diameter batang tanaman tebu P3 masing-masing 47% dan 59% lebih besar daripada batang tanaman kontrol pada 107 hari setelah tanam (HST).  [Kata kunci :biostimulan, tinggi tanaman, diameter batang, jumlah anakan, jumlah daun]

No abstract

Abstract

Silica (Si) in the form of soluble silicic acid [H4SiO4] was an element that makes plants more resistant to drought stress through biochemical or molecular processes and contributing to growth stimulation under biotic and abiotic stress conditions. The objective of this study was to determine the response of oil palm seedlings to drought stress by the bio-Si application. The experiment was arranged in complete random design (CRD) with ten replicates.  Bio-Si was developed in solid and liquid forms with a dissolved Si content at least 10% (w/v). The eight combinations of solid bio-Si application per seedling were: (i) blank (without fertilizers), (ii) 5 g NPK 15-15-15, (iii) 5 g NPK 15-15-15 + 109cfu of Si-solubilizing microbes (SSM), (iv-viii) 5 g NPK 15-15-15 + 2.5; 5.0; 7.5; 10 g bio-Si; and 5 g Na2SiO3.  On the other hand, liquid bio-Si application per seedling were: (i) blank (without fertilizers), (ii) 5 g NPK 15-15-15, (iii) 5 g NPK 15-15-15 + 109cfu of SSM, (iv-viii) 5 g NPK 15-15-15 + 25 mL; 50 mL; 75 mL; 100 mL bio-Si; and 50 mL Na2SiO3. Drought stress tolerance was analyzed by using proline concentration, nitrate reductase activity (NRA), chlorophyll content, and stomatal closure in the leave of oil palm seedlings. Based on the physiological response, this research indicates that bio-Si application could induce seedling tolerance to drought stress. The bio-Si treatments gave a positive response of proline concentration, nitrate reductase activity (NRA), chlorophyll content, and stomatal closure. The doses of 5 g NPK 15-15-15 + 7.5 g solid bio-Si and 5 g NPK 15-15-15 + 75 mL liquid bio-Si per seedling were a recommended to increase oil palm seedlings tolerance to drought stress.[Key words: bio-Si, chlorophyll, nitrate reductase activity, Si-solubilizing microbes]. AbstrakSilika (Si) dalam bentuk terlarut asam silikat [H4SiO4]merupakan unsur yang dapat menyebabkan tanaman lebih tahan terhadap cekaman kekeringan melalui proses biokimia atau molekuler dan menstimulasi pertumbuhan dalam kondisi cekaman biotik dan abiotik. Tujuan dari penelitian ini adalah mengetahui respons fisiologi bibit kelapa sawit yang diberi bio-Si terhadap cekaman kekeringan. Penelitian didesain dengan rancangan acak lengkap (RAL) dan sepuluh ulangan. Bio-Si dikembangkan dalam bentuk padat dan cair dengan kadar Si terlarut minimal 10 % (b/v). Delapan aplikasi bio-Si padat per bibit adalah: (i) blanko (tanpa pupuk), (ii) 5 g NPK 15-15-15, (iii) 5 g NPK 15-15-15 + 109cfu mikrob pelarut silika, (iv-viii) 5 g NPK 15-15-15 + 2,5 g; 5,0 g; 7,5 g; 10 g bio-Si, dan 5 g Na2SiO3. Sementara untuk aplikasi bio-Si cair per bibit adalah: (i) blanko (tanpa pupuk), (ii) 5 g NPK 15-15-15, (iii) 5 g NPK  15-15-15 + 109cfu mikroorganisme pelarut silika (MPS), (iv-viii) 5 g NPK 15-15-15 + 25 ml; 50 ml; 75 ml; dan 100 mLbio-Si, dan 50 ml Na2SiO3. Pengamatan yang dilakukan meliputi analisis prolin, aktivitas nitrat reduktase (ANR), kandungan klorofil, serta morfologi stomata pada daun bibit kelapa sawit. Berdasarkan data fisiologi yang diperoleh dari kegiatan penelitian ini, aplikasi bio-Si dapat meningkatkan ketahanan bibit kelapa sawit terhadap cekaman kekeringan. Perlakuan bio-Si memberikan respon positif terhadap konsentrasi prolin,aktivitas nitrat reduktase (ANR), kandungan klorofil, serta morfologi stomata.Dosis 5 g NPK 15-15-15 + 7,5 g bio-Si padat dan 5 g NPK 15-15-15 + 75 mLbio-Si cair dapat direkomendasikan untuk meningkatkan ketahanan bibit kelapa sawit terhadap cekaman kekeringan.  [Kata kunci: bio-Si, klorofil, aktivitas nitrat reduktase, mikroorganisme pelarut silika].