Laju fotosintesis pada tanaman kelapa sawit terinfeksi karat daun Cephaleuros virescen

Abstract

Kejadian penyakit karat daun kelapa sawit yang disebabkan alga Cephaleuros virescens semakin meningkat di Indonesia. Kerugian karena penyakit ini pada tanaman kelapa sawit belum pernah diukur secara kuantitatif. Penelitian dilakukan untuk mengukur laju fotosintesis pada tanaman kelapa sawit umur 5 tahun dengan 3 kategori serangan yaitu ringan, sedang, dan berat. Hasil pengamatan di Kebun Kalianta menunjukkan bahwa serangan karat daun dimulai dari pelepah bawah ke pelepah atas. Kejadian penyakit juga banyak terjadi pada permukaan atas helaian daun dibandingkan dengan permukaan bawah daun. Titik kritis serangan karat daun dimulai dari daun ke-17 ke atas yang akan menurunkan laju fotosintesis kelapa sawit. Pada daun ke-9 penurunan laju fotosintesis antara intensitas penyakit ringan ke berat sebesar 42.48% yaitu dari 15.51 µmol ke 8.92 µmol.

Fruitset quality of oil palm fresh fruit bunch over eight years in acid sulphate soil, Central Kalimantan

“…The trend line models in Figures 9 and 10 from the monitoring data show that the results of the correlation analysis of the data variables are appropriate and varied, namely, the relationship is very weak to very strong (Table 3). The concordance of the analysis results (positive and negative correlations) in Table 3 was obtained based on the research report [17,15], namely an increase in plant age along with an increase in fruitset value and inversely proportional to the number of anthesis male inflorescences. The result of analysis in Table 3 shows that the fruitset value had a very strong correlation (0.945) with the plant age and a very weak correlation (0.017) with the male inflorescences anthesis per Ha.…”

“…The decline in the quality of FFB based on the value of the fruitset apart from the possibility of being caused by the soil type factor is also thought to be caused by the reduced population of pollinating insects of E. kamerunicus in the oil palm plantation area. Purba et al [3] and Susanto et al [17] reported a decrease in the population of E. kamerunicus followed by a lower value of the FFB fruitset. Further reported by [21] about the decline in the value of fruitset in North Sumatera by ± 16% after 17 years after the initial introduction of E. kamerunicus.…”

“…x-axis which is 1 to 9 is for the year of observation Improvement in the quality of FFB can occur due to the effect of increasing the age of the plants which continue to enter their physiological maturation phase. Susanto et al [17] reported that the fruitset value of oil palm plants with different planting years showed higher yields at older plant ages, namely yop. 2010, 2006, and 2000 respectively valued at 66.7%; 72.9%; and 81.1%.…”

“…The highest number of anthesis male flowers was found in 2014 and 2019 (5 and 4) with the number meeting the standards to obtain a high fruitset value as a good quality FFB. The standard number of anthesis male inflorescences per hectare to get fruitset value ≥ 75%, that is 3 bunches of flowers [17]. Male inflorescence types on young oil palm plants will appear more with the sequence and proportion of irregular inflorescence production [15].…”

Ketahanan Beberapa Genotipe Kedelai terhadap Penyakit Karat Daun (Phakopsora pachyrizi)

“…Selain itu, karat daun juga dapat menyebabkan penutupan pada daun, sehingga luas permukaan daun yang aktif untuk proses fotosintesis menjadi berkurang (Sunpapao et al, 2017). Menurut (Susanto et al, 2020), penyakit karat daun dapat menyebabkan penurunan laju fotosintesis dan juga penutupan stomata pada daun.…”