Use of biostimulants in elephant grass cv. Napier

This study was developed to examine the growth, yield, chemical composition and in situ degradability of elephant grass cv. Napier (Pennisetum purpureum). Five spraying protocols with biostimulants were tested, namely, Control - no application; 1BR - bioregulator at seven days; 2BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days; 2BR2 - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor at 30 days; and 3BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor and bioregulator at 30 days. The grass was cut evenly at a height of 15 cm and harvested at 70 days of regrowth. The experimental area was divided into two blocks according to the slope. Ninety plots were used, totaling an area of 4,608 m2. Each plot was composed of four 4-m rows spaced 80 cm apart. Chemical composition, morphological traits and forage digestibility data were evaluated. The 3BR protocol, with more bioregulator-based applications, resulted in higher canopy (9.78%) and stem (9.58%) compared with control group. The 2BR and 2BR2 treatments provided a 6.5% higher stem than control treatment. The improvement in the nutritional value of Pennisetum purpureum cv. Napier was due to the 17.55% increase in crude protein (CP) content provided by protocol 3BR relative to control group. Treatments 2BR2 and 3BR improved the effective degradability of dry matter (DM). The application of biostimulant protocols increased the potential degradability of neutral detergent fiber (NDF) (+4.1%), with the greatest response seen in treatment 2BR2 in comparison with control treatment. Biostimulant protocols increase the canopy and stem heights and CP content. The application of a bioregulator associated with foliar fertilization and ethylene inhibitor improves the effective degradability of DM and NDF and the potential degradability of NDF in Pennisetum purpureum cv. Napier harvested at 70 days of regrowth.

Melatonin Relieves Ozone Stress in Grape Leaves by Inhibiting Ethylene Biosynthesis

Ozone (O3) stress severely affects the normal growth of grape (Vitis vinifera L.) leaves. Melatonin (MT) plays a significant role in plant response to various abiotic stresses, but its role in O3 stress and related mechanisms are poorly understood. In order to understand the mechanism of MT in alleviate O3 stress in grape leaves, we perform a transcriptome analyses of grapes leaves under O3 stress with or without MT treatment. Transcriptome analysis showed that the processes of ethylene biosynthesis and signaling were clearly changed in “Cabernet Sauvignon” grapes under O3 and MT treatment. O3 stress induced the expression of genes related to ethylene biosynthesis and signal transduction, while MT treatment significantly inhibited the ethylene response mediated by O3 stress. Further experiments showed that both MT and aminoethoxyvinylglycine (AVG, an inhibitor of ethylene biosynthesis) enhanced the photosynthetic and antioxidant capacities of grape leaves under O3 stress, while ethephon inhibited those capacities. The combined treatment effect of MT and ethylene inhibitor was similar to that of MT alone. Exogenous MT reduced ethylene production in grape leaves under O3 stress, while ethephon and ethylene inhibitors had little effect on the MT content of grape leaves after O3 stress. However, overexpression of VvACO2 (1-aminocyclopropane-1-carboxylate oxidase2) in grape leaves endogenously induced ethylene accumulation and aggravated O3 stress. Overexpression of the MT synthesis gene VvASMT1 (acetylserotonin methyltransferase1) in tobacco (Nicotiana tabacum L.) alleviated O3 stress and reduced ethylene biosynthesis after O3 stress. In summary, MT can alleviate O3 stress in grape leaves by inhibiting ethylene biosynthesis.

Pengaruh Kombinasi Konsentrasi 1-Methylcyclopropene dan Asam Askorbat terhadap Kualitas Ketahanan Simpan Pascapanen Buah Tomat Beef ‘Valoasis RZ’

Tomat beef merupakan salah satu jenis tomat eksklusif yang dapat menjadi peluang bisnis. Permasalahan pascapanen buah tomat adalah adanya lonjakan produksi etilen pada saat proses pematangan yang berakibat buah tidak dapat disimpan dalam waktu lama. Pematangan buah tomat dapat diperlambat salah satunya dengan cara menghambat produksi etilen dengan 1-Methylcyclopropene (1-MCP) yang berfungsi sebagai ethylene inhibitor dikombinasikan dengan asam askorbat (AA) sebagai oxygen scavenger. Tujuan penelitian ini adalah untuk menentukan kombinasi terbaik antara konsentrasi 1-MCP dan AA terhadap ketahanan simpan dan kualitas pascapanen buah tomat beef ’Valoasis RZ’. Penelitian dilaksanakan di Laboratorium Analisis Tanaman dan Pascapanen Hortikultura, Fakultas Pertanian Universitas Padjadjaran di Jatinangor. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap dengan 9 perlakuan dan 3 ulangan. Buah dipanen pada tingkat kematangan yang sama yaitu kulit buah berwarna pink. Buah diberi perlakuan kombinasi konsentrasi 1-MCP 0μL/L, 1 μL/L dan 2 μL/L dengan AA 0%, 2% dan 4%. Hasil percobaan menunjukkan bahwa kombinasi konsentrasi 1-MCP 1 μL/L dan AA 2% lebih efektif dalam meningkatkan ketahanan simpan buah tomat ‘Valoasis RZ’ dengan menghambat penurunan susut bobot buah selama 21 hari penyimpanan. Kombinasi konsentrasi 1-MCP 2 μL/L dan AA 4% memberikan hasil terbaik dalam mempertahankan kekerasan buah tomat beef selama 21 hari penyimpanan.

Strigolactone and Ethylene Inhibitor Suppressing Dark-induced Leaf Senescence in Perennial Ryegrass Involving Transcriptional Downregulation of Chlorophyll Degradation

Accelerated or premature leaf senescence induced by dark conditions could be associated with chlorophyll degradation and regulated by hormones. To study the effects of strigolactone (SL) on dark-induced leaf senescence and to examine the interaction effects of SL and ethylene on regulating dark-induced leaf senescence, plants of perennial ryegrass (Lolium perenne) exposed to darkness for 8 days were treated with a synthetic SL analogue (GR24), aminoethoxyvinyl glycine [AVG (an ethylene biosynthesis inhibitor)], or SL and AVG by foliar spray. Chlorophyll content, photochemical efficiency, electrolyte leakage, and ethylene production were measured. Expressions of genes associated with leaf senescence, SL biosynthesis and signaling, ethylene biosynthesis and signaling, and chlorophyll biosynthesis and degradation were determined. Foliar application of GR24 promoted leaf senescence in perennial ryegrass grown in darkness, and the intensity of action increased with the GR24 concentration. SL-accelerated leaf senescence was associated with the downregulation of four chlorophyll biosynthesis-associated genes and upregulation of four chlorophyll degradation-associated genes. AVG had functions counteractive to SL, suppressing dark-induced leaf senescence by downregulating chlorophyll degradation genes and SL synthesis genes. Our results suggested that SL and ethylene interactively regulated leaf senescence, mainly by controlling chlorophyll degradation induced by darkness in perennial ryegrass.

Comparative assessment of apple fruit storability during storage in different modes of the cooled medium

The article presents the research results of the effect of post-harvest treatment with Phytomag preparation of fruits of 21 apple tree varieties of domestic and foreign breeding on their storability and quality. The purpose of the research is to determine the effectiveness of the combined effect of such technological techniques as post-harvest fruit treatment with Phytomag preparation and their storage in conventional (CGD) and regulated (RGD) gas dynamics on the formation of quality and storability of apples grown in the Crimea. The data obtained showed that the treatment of fruits with an ethylene inhibitor Phytomag during storage in conventional and regulated gas dynamics reduces losses, depending on the variety, by 1.5-1.8 times. It is established that the processed fruits retain their original marketable appearance, have high quality components during the entire storage period and after opening the refrigerating chambers, selling the fruits and bringing them to the consumer. It is proved that in the conditions of the Crimea such varieties as Tavria, Krymskoye Zimnee, Krymskoye, Orion, Kimmeria, Brebern, Fuji, Idared, Pink Lady can be successfully stored in a conventional gas dynamic with post-harvest treatment with preparation inhibiting ethylene synthesis. The advantage of storage in regulated gas dynamic was shown by the varieties Aromat Kryma, Predgornoye, Golden Delicious, Crispin, Granny Smith, Glouster, Gala, Jonagold.